Explorando la ciencia con sensores y analisis de video

Exploring Science with Coach and €Sense

Heat and Temperature

Light Sound

April 2007, version 4.0 Hardware and software are distributed by the CMA foundation. The CMA foundation is affiliated to the AMSTEL Institute of Universiteit van Amsterdam.

AMSTEL Institute/CMA Foundation Kruislaan 404, 1098 SM Amsterdam, The Netherlands Telephone: +31 20 5255869 Fax: +31 20 5255866 E-mail: [email protected] Internet: http://www.cma.science.uva.nl/english © CMA / AMSTEL Institute, Amsterdam,

Text: Ewa Kędzierska, Piet Molenaar ©2007 Foundation CMA/AMSTEL Institute, Universiteit van Amsterdam

Exploring Science - Exploring Heat and Temperature 3

Table of Contents

PART I - TEACHER’S NOTES................................................................................................................ 5 1. COMPUTER BASED ACTIVITIES FOR SCIENCE INVESTIGATIONS .............................................................................. 5 2. EXPLORING SCIENCE ACTIVITIES........................................................................................................................ 5

2.1. The most important feature – graphs ...................................................................................................... 5 2.2. Learning objectives which can be reached in presented activities.......................................................... 6 2.3. Student’s worksheets .............................................................................................................................. 6

PART II - PUPIL’S WORKSHEETS ......................................................................................................... 7

EXPLORING HEAT AND TEMPERATURE .............................................................................................. 7 WORKSHEET 1. HOT! COLD! WARM!....................................................................................................................... 8 WORKSHEET 2. TELL A STORY ABOUT TEMPERATURE............................................................................................ 10 WORKSHEET 3. MUM, MY TEA IS COLD.................................................................................................................. 12 WORKSHEET 4. ANIMAL FAMILY............................................................................................................................ 13 WORKSHEET 5. WHAT IS HEAT? WHAT IS TEMPERATURE?..................................................................................... 15 WORKSHEET 6. WARMING UP AND COOLING DOWN ............................................................................................... 17 WORKSHEET 7. HOW TO COOL DRINKS FASTER?................................................................................................... 19 WORKSHEET 8. HOW TO KEEP WARM? ................................................................................................................. 21 WORKSHEET 9. HOW IS HEAT TRANSPORTED?...................................................................................................... 23 WORKSHEET 10. HEAT ABSORPTION .................................................................................................................... 25

EXPLORING LIGHT ............................................................................................................................ 27 WORKSHEET 1. HOW BRIGHT?............................................................................................................................. 28 WORKSHEET 2. HOW DOES LIGHT TRAVEL? ......................................................................................................... 30 WORKSHEET 3. TELL A STORY ABOUT LIGHT ......................................................................................................... 32 WORKSHEET 4. FLASHING LIGHT .......................................................................................................................... 34 WORKSHEET 5. HOW MUCH LIGHT PASSES THROUGH? .......................................................................................... 36 WORKSHEET 6. REFLECTED LIGHT ....................................................................................................................... 38 WORKSHEET 7. THE BRIGHTNESS OF COLORS....................................................................................................... 40 WORKSHEET 8. DOES THE BRIGHTNESS CHANGE THE FURTHER AWAY?.................................................................. 41

EXPLORING SOUND .......................................................................................................................... 43 WORKSHEET 1. HOW LOUD?................................................................................................................................ 44 WORKSHEET 2. TELL A STORY ABOUT SOUND ....................................................................................................... 47 WORKSHEET 3. MAKE SOUND VISIBLE .................................................................................................................. 49 WORKSHEET 4. ANALYSIS OF VOICE SOUNDS........................................................................................................ 51 WORKSHEET 5. ANALYSIS OF INSTRUMENTS SOUNDS............................................................................................ 53 WORKSHEET 6. HOW DOES SOUND TRAVEL? ........................................................................................................ 55 WORKSHEET 7. WHAT IS THE BEST WAY TO STOP SOUND? .................................................................................... 57 WORKSHEET 9. DOES SOUND GET MORE QUIET FURTHER AWAY? .......................................................................... 59



Part I - Teacher’s notes

1. Computer based activities for science investigations Observations and measurements are central features of practical activities in science. Traditionally, students are taught to use different measuring instruments. Then they record their collected data in a table and plot them in the form of a graph. Now all these activities can be easily performed with a computer. What are the benefits of doing these activities with a computer? Many of the benefits arise from the computer’s facilities to: - collect data from many different sensors (simultaneously, if necessary) - display data as numbers, meters, graphs, and tables - process (perform calculations on) and analyze data. Computers perform all these tasks quickly and accurately, easily dealing with large quantities of data collected over either very short or very long periods of time. Displaying data as it is being collected reinforces the link between an experiment and its results, so students get a better feeling for quantities and their changes.

It is very easy to work with Activities in the Coach 6 (Lite) program. The instructions for the students can be very simple and their attention focuses on science investigations. Manipulating the computer does not take a lot of time and attention.

2. Exploring Science Activities Exploring science consists of the following Coach Projects:

• Exploring Heat and Temperature • Exploring Light • Exploring Sound • Own Lab.

These projects contain twenty nine Coach activities for €Sense and its temperature, light and sound sensors. The activities are designed for students between 11-14 years old.

In these activities students explore and investigate phenomena involving light, sound, heat and temperature. Students get a number of problems that have to be solved by taking measurements with sensors. The Own Lab Activity, included in the Coach project ‘Measurements in Own Lab’, allows students to setup and perform their own experiments with €Sense. 2.1. The most important feature – graphs The traditional process of plotting graphs of experimental results leaves little time for pupils to consider the meaning of the graphs. Computer measurement activities create many opportunities for exploring data and help to focus student attention on the interpretation of graphs. One of the most important features of these activities is that every measurement is directly presented in graph. This visual representation of the data helps pupils to understand the relationship between a phenomenon (a real measurement) and its graphical representation. Experiments are easy to repeat so students have enough time to observe phenomena, check their own predictions and interpret results.


Learning with graphical presentations is very important. A great deal of information can be conveyed efficiently with graphs. Students have highly developed visual skills, and it has been found that visual activities have a large influence on cognitive development. It is also important that there be very little delay between the physics experiment and the visual information. Then there is a connection between the science and the graphs, increasing the chances for students to achieve understanding of science concepts. There are at least three levels of interpreting graphs. At the first, qualitative level, the graph shape may be inspected, identifying trends and interesting features. Students can try to explain what may be going on in an experiment. Very important also is the effect of scale on the shape of the graph (concept: the rate of change). At the second, semi-quantitative, level, students compare graphs and explain similarities and differences. Finally, the quantitative level of interpreting graphs involves obtaining information from graphs, reading values and performing simple calculations. 2.2. Learning objectives which can be reached in presented activities Using computers with sensors supports doing science investigations, which involve collection of information, planning, measuring, hypothesizing and analyzing. In Exploring Science students are involved in all these areas. The more specific learning objectives which can be reached in the activities are: • students should be able to set up the equipment, to use IT equipment and to be

responsible for the equipment. • students should know how to work with the program (start the program, projects and

activities, make measurements, print information etc.) • students should be able to perform an activity, describe what they are doing, give and

follow the instructions, ask questions, and work in-groups. • students should be able to use the information from graphs/diagrams:

- read values from a graph, - zoom a part of a graph, - determine the scale of a diagram, - interpret data.

• students should be able to make a report of an activity in which they record and discuss what they have done.

2.3. Student’s worksheets Each student’s worksheet is started with easy introductory observations, questions and experiments to introduce a problem for investigation. Then the experiments using the computer and sensors performed.


Part II - Pupil’s worksheets

Exploring Heat and Temperature

Activities: 1. Hot! Cold! Warm! 2. Tell a story about temperature 3. Mum, my tea is cold 4. Animal family 5. What is heat? What is temperature? 6. Warming up and cooling down 7. How to cool drinks faster? 8. How to keep warm? 9. How is heat transported? 10. Heat absorption


Worksheet 1. Hot! Cold! Warm! Hot! Cold! Warm! Cold! Can you tell which is which? Can you explain these terms? Observation Obtain three pans. Fill one with cold water, another with lukewarm water, and the third one with water that is as hot as your hand can bear. Place one of your hands in the cold water and the other in the hot water. After a few minutes place both hands in the lukewarm water. 1. With both hands in the lukewarm water, do they feel different from one another?

Yes/No 2. Describe the feeling of the lukewarm water as sensed by each hand.

The right hand The left hand

3. Try to guess the temperature of the water in each of the pans of water. Check your

guesses with a thermometer. How accurate were your guesses?

As you can probably see, you are not a very precise thermometer. With your hands you can not exactly tell how warm things are. For the temperature measurement you need a thermometer. In this activity you are going to measure temperature of different objects with the computer and the temperature sensor. Remember to keep water far from the computer.


1. Start the project ‘Exploring heat and temperature’ and the activity ‘Hot! Cold! Warm!’.

Connect the external temperature sensor to €Sense (as shown in Coach).. When the temperature sensor is connected correctly the measured temperature is shown on the sensor icon.

The measured by the sensor temperature is also displayed on a meter and as a digital value. Temperature is measured in 0C (Celsius or centigrade) The temperature measured by the sensor is _____________ 0C.

2. Now you are going to measure temperature of different objects. After each measurement

fill in the proper cell in the table below.

I measure Temperature 0C

in cold water

in lukewarm water

in hot water

in the air

in your hand

in glove with a hand inside

under my arm

Does the temperature sensor need some time to warm up or cool down? How can you see this?

Explain in your own words what temperature is.


Worksheet 2. Tell a story about temperature Does energy radiated from the sun raise the temperature of the world during the day? Imagine a summer day, how do you think temperature will change during such a day? Start your story at 4.00 am and finish at 11.00 pm. In this activity you are going to tell a story about the temperature change. You will tell this story based on a graph that you would see on the computer screen. (Remember to keep water far from the computer!) 1. Start the project ‘Exploring heat and temperature’ and

the activity ‘Tell a story about temperature’. Connect the external temperature sensor to €Sense. (Remember to keep water far from the computer).

2. In one of the panes on the screen you see the diagram

“Temperature in 0C”. Along the horizontal axis you see the time in seconds and along the vertical axis you see the temperature in 0C. Look at the red cross on the vertical axis.

The cross goes up when the temperature __________________________________ The cross goes down when the temperature ________________________________

3. Take two containers, one with cold

water and one with hot water. Hidden from your view, a classmate will dip the temperature sensor slowly in and out of these two containers. Your job will be to look at the temperature graph and guess which container the temperature sensor was placed in first. When your classmate is ready to begin, click the green Start button to record the temperature. Sketch the temperature graph from the computer screen on these axes. When was the temperature graph dipped into the hot and cold water? Label those points on your diagram. Write a story about the temperature.


4. In England and the United States temperature is measured in 0F (Fahrenheit degrees). It

is easy to convert a temperature reading from one scale to another if you have a formula to follow. The temperature graph recorded during the experiment can be presented in 0F. Click the Panel Window button. A new diagram labeled “Temperature in 0F” appears on the screen. Now look at both graphs. What is the difference between the scales of these two graphs?

Is there any difference between the red and the blue measuring curves?

Extra: The formula for converting a Celsius reading (TC) to the Fahrenheit scale is:

TF =9

5TC + 32

⎛ ⎝

⎞ ⎠

0F

The formula for converting a Fahrenheit reading (TF) to the Celsius scale is:

( ) CTT FC032

95

−=


Worksheet 3. Mum, my tea is cold You have a cup of hot tea, but you are busy playing a computer game. You want to finish the game before drinking tea. After ten minutes you drink your tea. Is your tea still warm? Yes/No What happened to your tea? Do you know why? While your tea was cooling, what do you think happened to the air around it? In this activity you will measure the temperature of a cup of tea as it cools down. 1. Start the project ‘Exploring heat and temperature’ and the activity ‘Mum, my tea is cold’.

Connect the external temperature sensor to €Sense. 2. Take a plastic beaker. Fill the beaker with hot tea and place the temperature sensor

inside. Remember to keep liquids far from the computer. Look at the sensor icon and read the beginning temperature of the tea____________ .

3. Do you know how the temperature is

changing when the tea is cooling? Draw a prediction graph in Coach.

4. Start the measurement by clicking the

green Start button.

Draw both graphs (in blue your prediction, in red your measurement) in the diagram. What is the difference between these two graphs?


Worksheet 4. Animal family As you probably know, animals are warmer than their surroundings and they constantly lose heat energy through their surfaces. Sometimes baby animals die from the cold at temperatures adults live in without any problem. Try to explain why a baby animal cools off more quickly than an adult animal. In this activity you will compare the temperatures of a baby animal and an adult to see which animal is getting colder first. 1. Start the project ‘Exploring heat and temperature’ and the activity ‘Animal family’.

Connect the external temperature sensors to €Sense. 2. Take a large and a small container. These containers will represent an adult animal and a

baby animal. 3. Place the temperature sensor in the large container and fill it with hot water. Click the

Start green button to measure the temperature. The measurement takes 5 minutes. 4. To be able to compare (in one diagram) results from the first experiment with the results

of the second experiment you have to store your first data run in the diagram. You do it by right-clicking the diagram, selecting first Copy Column an then T.

5. Repeat the experiment but now for a small container. Place the temperature sensor in the

small container and fill it with hot water. Take care that the water temperature at the beginning is the same as for the large container (for example in both experiments use hot water from a thermos). Click the Start green button to measure the temperature.


Using two different colors draw the resulting graphs in the right diagram. What was the temperature at the beginning of the measurement in both containers?

What was the temperature at the end of the measurement for: Adult animal: ________________ Baby animal:________________ What animal gets cold faster? Explain how you know this.


Worksheet 5. What is heat? What is temperature? The thermometer or the temperature sensor is a tool we can use to study heat, but it does not measure heat. It measures temperature. The difference between heat and temperature may be shown by a simple example. You can put one drop of boiling water on your skin without harm or pain. Each drop of boiling water has a temperature of 100 0C, but one drop contains very little energy. A drop of boiling water has a high temperature but it has little heat. Only when many drops are put together there will be much heat. Heat can come from many places and usually (but not always) it makes things hotter. What kind of heat sources do you know? Do you know in what units heat is counted? In this activity you will learn about the difference between heat and temperature. 1. Start the project ‘Exploring heat and temperature’ and the activity ‘What is heat? What is

temperature?’ Connect the external temperature sensor to €Sense. Experiment 1 1. Take a pan and fill it with 100 ml water.

Place the temperature sensor in the water and cover the pan with foil. The cover prevents heat from being lost to the air.

2. Start to heat the pan and click the green Start button to start the measurement. You are going to measure the water temperature for 3 minutes. When the measurement is finished draw a graph with a red pen.

3. Now fill the same pan with 200 ml water. The water should have the same beginning temperature as for the measurement. Place the temperature sensor inside the pan and cover the pan with foil.


4. Heat the pan in exactly the same way for exactly the same time (three minutes) as in the first experiment. Start the measurement by clicking the Start button. Draw a resulting graph with a blue pen. The beginning temperature in both experiments was: __________ Has the same amount of heat gone into the pane in each experiment? Yes/No Explain why_______________________ After heating the 100-ml sample the end temperature is: __________ After heating the 200-ml sample the end temperature is: __________ The change of temperature (in 3 min) for 100-ml is: __________ The change of temperature (in 3 min) for 200-ml is: __________ Try to explain in your own words the difference between these two experiments.

Experiment 2 1. Put the broken ice in a pan with water.

Place the temperature sensor inside the ice. Stir it slowly.

2. Start the measurement. Record the temperature while the pan is heated on a hot plate.

3. Draw a graph. What happens to the ice and water during the experiment?

Try to explain what happens to the temperature during the experiment?


Worksheet 6. Warming up and cooling down Fill the test tube with crystals of Stearic acid. Place the test tube in a water bath. Warm up the water bath and observe what happens to the Stearic acid. Describe what happens to the Stearic acid? Did the Stearic acid melt immediately, or did it take some time? In this activity you will measure the temperature of the Stearic acid as it cools down. 1. Start the project ‘Exploring heat and temperature’ and the activity

‘Warming up and cooling down’. Connect the external temperature sensor to €Sense.

2. Place the temperature sensor inside the test tube with melted Stearic

acid. If necessary, warm up the water bath a little bit to melt all the Stearic acid around the temperature sensor. With this temperature sensor you will measure the temperature of the Stearic acid.

3. Prepare a second, cold, water bath. 4. Remove the Stearic acid tube from the warm water bath and place it in

the cold water bath. Click the green Start button to start the measurement. You are going to record the temperature of the Stearic acid for 10 min. Stir the Stearic acid continuously.

5. Draw the resulting measurement graphs

in different colors in the diagram.

Look at the graph of the cooling Stearic acid. Describe how the temperature is changing.


What happens to the Stearic acid when the graph is flatter?

An interesting thing happens in lakes and other bodies of water when the air temperature drops below the freezing point of the water.

You know that ice forms on the surface of lakes and the ice floats in water. Water does not act like other substances as it approaches its freezing point. Water contracts and becomes denser as it is cooled to 4 0C. From 4 0C to 0 0C, it begins to expand again. As water expands it becomes less dense than the water surrounding it and rises to the top again. It continues to expand as it freezes at the surface. The sheet of ice at the surface acts as an insulator. It prevents the escape of heat from the water below the ice. Fish and other animals are able to live under the sheet of ice during the winter.


Worksheet 7. How to cool drinks faster? When the water is warm and the air is warm, why should you be cold when you come out of the water? 1. Place a drop of perfume on your arm.

Describe what you feel.

2. You have a beaker of really hot chocolate.

You would like to drink it as soon as possible. What do you do to help your drink cool off? I cool my chocolate by: 1______________________________ 3_____________________________

2______________________________ 4_____________________________ In this activity you will try to find the ways which can speed up the process of cooling. 1. Start the project ‘Exploring heat and temperature’ and the activity ‘How to cool drinks

faster?’ Connect the external temperature sensor to €Sense. Experiment 1 1. Dip the temperature sensor into some perfume (after-shave, perfume or methanol) and lift

it out to allow evaporation. Click the green Start button to start the measurement. What happens to the temperature?

2. Wave the wet temperature sensor around in the air. Does it get colder or warmer? Do

you know why?

Experiment 2 1. Pour hot water into a thermos. You will use this water in several experiments, and in every

experiment the beginning water temperature should be the same. 2. For each experiment, pour the same amount of hot water from the thermos into a beaker.

Cool the water in different ways, but for the same period of time (250 s). 3. Fill in the table on the next page.


The way of cooling down The temperature at the beginning is

The temperature at the end is

Leaving a spoon in the drink

Placing a lid on the drink

Using a fan

....................

....................

What is the fastest way of cooling your hot drink? How do you know?

What happens to heat when the drink cools down? Try to explain every case.

Some more investigations 1. When you do anything energetic, like running

round the school field, you get warm or even really hot. How does your body cool you down? How can you cool yourself down? (You can study this problem by measuring the temperature of your hand while keeping the hand inside a closed plastic bag).

2. Do you know how elephants keep cool? They use the surface area of their large ears as heat radiators. (You can study this problem by measuring the temperature inside a can of water. The can should be wrapped in aluminum foil and have two large “ears” made also from aluminum foil).

3. If you got wet in the rain would your wet clothes make you warmer or would they make you colder? (You can study this problem by measuring the temperature inside a wet glove.)


Worksheet 8. How to keep warm? It is winter. You are going to walk during a very cold day. How would you dress for such a day? If you want to keep yourself warm, which is better—one thick sweater or several layers of thinner clothes? As you know from your own experience (and also saw in the previous activity) when you want to keep water hot, you keep it in a thermos. Do you know why water inside a thermos stays warm? In this activity you are going to find out the best way of keeping things warm. 1. Start the project ‘Exploring heat and temperature’ and the activity ‘How to keep warm?’.

Connect the external temperature sensor to €Sense. 2. Pour hot water into a thermos. This water will be used in a few experiments, and in every

experiment the beginning water temperature should be the same. 3. Take a container. Place the temperature sensor inside the container and pour hot water

from the thermos into it. 4. Click the green Start button to start the temperature measurement. Measure the

temperature as the water in the container cools down. 5. To be able to compare (in one diagram) results from the first experiment with the results


6. Repeat the experiment but now wrap the container loosely in cotton wool, and then place

it in a carton box. 7. Place the temperature sensor in the container and pour hot water from the thermos into it

(in this way the beginning temperature for both experiments is the same). Click the green Start button to start the temperature measurement.


8. Draw the resulting graphs from both

experiments.

Which of the containers is getting cool faster?

When will the insulated container reach the same temperature as the un-insulated one?

9. Now you are going to repeat the experiment but you will use different insulators. Fill in the table below.

Insulator The beginning temperature for both containers

The end temperature of un-insulated

container

The end temperature of

insulated container

Wool

Cotton fabric

Elastic bands

...............

................

What is the most effective insulator?

How do you know it?

What happens when you wrap the container in an aluminum foil?


Worksheet 9. How is heat transported? When you are near a fire or a radiator, or when you touch a spoon that has been inside a hot pan you experience the effect of heat transfer. How does the heat get from one place to another? Explain how your house is heated in the winter. How is heat transported to all rooms? Place a wooden spoon and a metal spoon in a pan of hot water. Do you notice a difference when you touch the spoons? Why does one spoon feel so much hotter than the other? Is the following sentence true or false? (Give some examples.)

In normal conditions, heat energy always moves from a warmer to a cooler object. In this activity you will investigate how heat can be transported from one place to another. 1. Start the project ‘Exploring heat and temperature’ and

the activity ‘How heat is transported’. Connect the external temperature sensor to €Sense.

2. Fill one container with water. Place the container on a

plate heated by the burner. Heat the water until it boils. 3. Fill a Styrofoam cup with 50 ml of cold water. Cover the

cup. The cover prevents heat from being lost to the air. 4. Position a U-shape piece of copper as shown in the

picture. One end of the copper wire should be placed in the boiling water and the other end should extend through a hole in the cover of the cup to the cold water. Insulate the part of the copper rod that is not in the water by wrapping it with fabric. You can also use a piece of electric wire in which its isolation is removed at both ends.


5. Place the temperature sensor into the cold water through another hole. 6. Between containers set up the barrier to

protect the Styrofoam cup from the burner.

7. When you are ready, click the Start

button to measure temperature in Styrofoam cup. Keep water boiling in the first container.

8. Draw the resulting graph with a red pen. 9. Repeat the experiment but instead of

copper use a U-shape piece of plastic. 10. Draw a graph of the temperature in the Styrofoam cup with a blue pen.

In which case is the water inside the Styrofoam cup warmer at the end of the measurement?

How was heat transported to the water?

Which material is a better heat conductor?

Do you know other materials which are good heat conductors?


Worksheet 10. Heat absorption Radiation from the sun tans our skin, lights up our world, heats the ground and indirectly heats the air around us. The sun is not only a source of light but also a source of heat energy. Take two small cartons, one painted white and the other painted black. Place one hand inside the white box and the other one inside the black box. Find a sunny place. Let sunlight warm the boxes. (If you don’t have cartons you can use white and black pieces of fabric and place your hands under the fabric.) • Do your hands feel the same temperature? Describe

what each hand feels:

The hand in the white box The hand in the black box

• Which box absorbs more heat energy? Explain why you think that.

In this activity you will learn that the different colors absorb different amounts of heat energy. 1. Start the project ‘Exploring heat and temperature’ and

the activity ‘Heat absorption’. Connect the external temperature sensor to €Sense.

2. Wrap the temperature sensor in white paper. 3. Place the sensor in a sunny place or at the small

distance from an electric bulb. 4. Click the Start button to start a measurement. 5. To be able to compare (in one diagram) results from the first experiment with the results



6. Repeat the experiment but now wrap the temperature

sensor in black paper. 7. Click the Start button to start a measurement. Take care

that the beginning temperature of the temperature sensor is the same in both experiments.

8. Draw the two resulting graphs in different colors in the

diagram.

Did the sensors warm up at the same rate?

Which of the sensors got warmer?

9. Try the investigation again using other colors of papers (or fabrics) like pink and green,

yellow and dark blue etc. Answer the following questions based on your investigations:

Which color clothes would you wear to stay cool on a hot sunny day? Which color clothes would you wear to stay warm on a bright winter’s day?

Exploring Science - Exploring Light 27

Exploring Light

Activities: 1. How bright? 2. How does light travel? 3. Tell a story about light 4. Flashing light 5. How much light passes through 6. Reflected light 7. The brightness of colors 8. Does the brightness change further away?


Worksheet 1. How bright? A night lamp in your bedroom does not give a lot of light, so you can fall asleep with it. Sunlight is much stronger. It is so bright that if you look at the sun it hurts your eyes. Here are eight light sources:

the Sun the Moon lightning a fluorescent lamp,

a car reflector an electric bulb a torch a candle. Put the light sources in order from brightest to weakest. Start with the Sun, which is the brightest light source. Fill the table below.

Place The light source

1 Sun

2

3

4

5

6

7

8

In this activity you are going to measure the brightness, or in other words light intensity, of different light sources with the light sensor. 1. Start the project ‘Exploring light’ and the activity ‘How bright?’. The light sensor icon is

already on the €Sense panel. 2. On the screen you see a digital number. This is the light intensity (brightness) measured by

the light sensor. The light intensity is measured in %.


A light intensity of 0% means there is no light. A light intensity of 100% means there is a lot of light.

Direct the light sensor at the brightest light. Read how strong the light is. The light intensity is _____________________%.

3. Cover the sensor with your hands while it is pointing towards the light.

The light intensity is _____________________%. 4. Now you are going to measure the light intensity of the following light sources. Keep the

light sensor at the same distance from each light source (for example, measure brightness 3 cm away from the light source). Fill in the table below.

The light source The light intensity %

A candle

A torch

A light bulb

...............

................

................

Which of the light sources gives the most light?

Do you know why you have to keep the light sensor at the same distance from each light source?


Worksheet 2. How does light travel? If you have ever seen the beam of light from a flashlight you probably have noticed how light travels. Look at the photos. They will help you answer questions.

Does a beam of light seem to bend around corners? Does light zigzag its way to an object? Make a cross from a card. Stick the cross to the wooden rod as it is shown on the picture. Take a lamp or other light source and direct its light at the cross. Arrange it so that a clear shadow of the cross appears on a screen or on a white wall. (If it is too light in the classroom, make it darker by closing curtains) Hold a piece of string so that one end touches the lamp and the other end touches the edge of the shadow. The string should be pulled tight. Try different places on the edge of the shadow. Write down what you found out. Finish the following sentence: The light beam travels ______________________________. You are going to observe how light travels. You will measure the light intensity around a light source. 1. Start the project ‘Exploring light’ and the

activity ‘How does light travel?’. The light sensor icon is already placed on the €Sense panel.

2. Place a candle in the middle of a circle. Divide the circle as shown on the picture. You are going to record the light intensity at different points around the


circle. 3. Place €Sense with the light sensor at one of the circles and point it at the candle.

Remember to keep the light sensor at the same distance from the candle during the measurement.

4. In this measurement you will use the manual mode. First click the green Start button. On the screen, another green manual measurement button (with the hand) appears. When you are ready to make a measurement, click this button. At this moment the reading of the light intensity is taken and you have to type a number of the reading.

5. Move the light sensor one interval around the circle and repeat the procedure: click the green button to take the light intensity measurement and type the number of this measurement. When you have finished making measurements click the red button. Fill in the table below based on the table on the screen.

Number Light intensity

1

2

3

4

5

6

7

8

How is the light intensity changing around the candle?

Does light come from the back and the sides of the candle (or another light source)?

6. Finish the sentence: light spreads out in _____________ from a light source. 7. Explain why we have to use reflectors or lamp shades.


Worksheet 3. Tell a story about light It is a sunny day in June, but clouds appear from time to time. Around 16.00 o’clock the sky becomes darker and heavy rain clouds appear. It starts to rain at about 16.30. At 18.30 it is sunny again. On this day you decide to record the light intensity of sunlight with the light sensor. The light sensor hangs outside a window and it is pointed towards the sky. Draw how the light intensity changes during this day. The graph starts at 6.00 o’clock in the morning. Write down a story about your graph. In this activity you are going to tell a story about the changing of the light. You will tell this story based on a graph you see on the screen. 1. Make three identical cloud shapes: one from a white

card, one from grey thin paper and one from black transparent foil.

2. Start the project ‘Exploring light’ and the activity ‘Tell a

story about light’. The light sensor icon is already placed on input 1 of €Sense.

3. Point the light sensor at the light source (a lamp or a

window). In one of the windows on the screen you see a digital number. This is the light intensity measured by the light sensor.

4. Pass the white cloud in front of the light sensor. Write down the light intensity measured at

this moment. Do the same for two other clouds.

The light intensity measured with no clouds is __________________________ The light intensity measured for the white cloud is __________________________


The light intensity measured for the grey cloud is __________________________ The light intensity measured for the black cloud is __________________________

5. Look at the graph now. Along the horizontal axis you see the time in seconds and along the

vertical axis you see the light intensity in %. Look at the red cross on the vertical axis.

The cross goes up when the light intensity__________________________________ The cross goes down when the light intensity________________________________

6. Now you are going to play a game with your classmate. Hidden from your view, the

classmate will pass different clouds: the white, the grey or the black in front of the light sensor. You will look at the graph on the screen and guess which of the clouds your classmate used. When your classmate is ready, click the green Start button to record the light intensity.

7. Draw a measurement graph in the diagram.

8. Tell which of the clouds was placed in front of the light sensor and when. Write down your

story.


Worksheet 4. Flashing light The computer screen produces light. Put your eyes near the computer screen and look carefully. Do you see anything unusual? Is the light flashing? Yes/No In this activity you will investigate the light coming from the computer screen and other light sources. 1. Start the project ‘Exploring light’ and the activity ‘Flashing light’. Connect the light sensor to

input 1 of €Sense (as shown in Coach). 2. Look at the diagram on the screen. Time is measured in milliseconds.

(A thousand milliseconds add up to one second).

The measurement time is very short and takes ________________ ms. 3. Direct the sensor at a white part of the computer screen. Start the measurement by clicking

the green Start button.

Is the light from the computer screen flashing? Yes/No

4. If the computer screen flashes (goes up and goes down) ______________ times in the measurement time.

The graph goes down when there is more / less light. The graph goes up when there is more / less light.

5. Read the light intensity from the graph (zoom in if necessary.)

When the light is brightest then the light intensity is _________________ %. When the light is least bright then the light intensity is _________________ %.

6. Now you are going to find other light sources which are also flashing. Repeat

measurements and fill the table below.


The light source

The light: (Mark the best answer)

The computer screen

O is constant O flashes 1 time per second O more often than 1 time per second

An electric bulb


A TL lamp


A torch


Which of the light sources gives flashing light? Which of the light sources gives constant light?

7. In this activity you have discovered that light can flash even when it looks constant. Why

can not you see the flashing light with your eyes?

8. The computer screen turns on and off very quickly. The light intensity decreases to zero

percent, where there is no light. The TL lamp flashes also but the light intensity does not reach zero percent. What does that mean?


Worksheet 5. How much light passes through? In the summer the sun can be very bright. Sunglasses help protect you from bright sunlight. But some sunglasses are better than others. Collect different sunglasses. Try every pair of sunglasses. Which pair of sunglasses appears to be most effective? Why? With some materials you can block light. In this activity you will try to find the material which is best at blocking light. With the light sensor you will measure how much light can pass through different materials. 1. Start the project ‘Exploring light’ and the activity ‘How much light passes through?’.

Connect the light sensor to input 1 of €Sense (as shown in Coach). 2. In this experiment you should try to make a fair test for all materials. Point the sensor

towards the light source. 3. Place the piece of materials to test in front of the light sensor and read how much light

passes through it. 4. Test different materials like: glass, wood, card, foil, different fabrics, different papers. Fill in

the table below.

Material The intensity of light passing through

Glass

Wood

Plastic foil


Material The intensity of light passing through

................

.................

..................

..................

Which material is the best at blocking out lights? Is thick or thin material better?

5. As you probably have observed in your activity there are three types of materials.

Materials that you can see through are called transparent. Materials that do not allow the passage of light are called opaque materials. Some materials cannot be seen through, but do allow some light to pass through them. Such materials are called translucent materials. Place each of tested material in one of the columns.

Transparent materials

Opaque materials

Translucent materials

Which material would be the best for a window blind?

Which material would you use for a bathroom window?

Which material should be the best for a parasol?


Worksheet 6. Reflected light Place a pan almost full of water near a window so that sunlight falls on it. Look for a bright spot on the wall or ceiling. Explain why the bright spot appears on the wall (or ceiling). Strike the side of the pan with the hand just hard enough to cause the surface of the water to form ripples. What happens to the spot of light? Is the spot still bright and sharp? In this activity your are going to find out what kind of materials can reflect light. 1. Start the project ‘Exploring light’ and the activity Reflected light’. Connect the light sensor to

input 1 of €Sense (as shown in Coach). 2. Take a bright lamp which illuminates your table well. 3. Put the samples of different materials (foil, mirror, shiny and dull fabrics of the same color,

fluorescent materials) on the table. 4. Fix the light sensor so that it points towards the sample. To make a fair test you must keep

the sensor at the same distance from the sample for each measurement (10 cm, for example). Use the light sensor to measure the intensity of light reflected from each sample. Fill in the table.


Material Intensity of reflected light in %

Wood

Glass

Foil

Red foil

Red paper

…...

Which surface reflects the most light? ______________________________________

What kind of material is the best to wear in the dark if you want to be easily visible? Why?


Worksheet 7. The brightness of colors In a famous experiment, Isaac Newton allowed a beam of light to enter a darkened room and strike a screen. When a prism was placed in the path of the light beam, a band of rainbow-like colors was projected on the screen. He found that if the colored beams from the prism were passed through another prism, the result was white light again. Repeat Newton’s experiment. Describe the order of colors you see in the spectrum. In this activity you will investigate the brightness of different colors. 1. Start the project ‘Exploring light’ and the activity ‘the brightness of colors’. Connect the light

sensor to input 1 of €Sense (as shown in Coach). 2. Take a bright lamp which illuminates your table well. 3. Put samples of different colors (papers or fabrics) on the

table. 4. Fix the light sensor in such a way that it points towards

the sample. To make a fair test you have to keep the sensor at the same distance from the sample for each measurement (for example 10 cm). With the light sensor you can measure how much light is reflected from each color sample. Fill in the table.

Material Intensity of reflected light in %

Black

White

Red

Green

Yellow

……..

Which color is the brightest? ___________________________________________

What color clothes should we wear in the dark if you want to be easily visible?


Worksheet 8. Does the brightness change the further away? As you already know, light spreads out in all directions from a light source. Take a book and open it. Illuminate your book with a lamp. If there is still not enough light to comfortably read the book, what could you do to get better illumination for your book? Now bring the book closer to the lamp. How does this affect the illumination? In this activity you are going to investigate connection between the distance from a lamp and light intensity. 1. Start the project ‘Exploring light’ and the activity ‘Does the brightness change further

away?’ Connect the light sensor to input 1 of €Sense (as shown in Coach). 2. You are going to type values for the distances between the light bulb and the €Sense light

sensor and the program will measure the light intensity. 3. Position the light sensor so that it is facing the light bulb and the distance between the light

sensor and the centre of the bulb is 5 cm. 4. First click the green Start button to start a measurement. Then click the Manual Start. At

this moment the reading of light intensity is taken. You have to type the distance between the lamp and the sensor.

5. Move the light sensor 3 cm further away from the centre of the bulb. Repeat procedure:

click the Manual Start button to measure the light intensity, and then type the distance value.

6. Move the light sensor 3 cm further several times, measuring light intensity each time. When

you have finished, click the red stop button. 7. Look at the graph on the screen. Draw this graph in the diagram.


8. Describe how the light intensity changes when the distance between the light sensor and the light source increases.

Exploring Science – Exploring Sound 43

Exploring Sound

Activities: 1. How loud? 2. Tell a story about sound 3. Make sound visible 4. Analysis of voice sounds 5. Analysis of instruments sounds 6. How does sound travel? 7. What is the best way to stop sound? 8. Does sound get quieter further away?


Worksheet 1. How loud? There are sounds around you all the time. Sometimes you do not notice them but you can hear them if you listen carefully. If you sit quietly and close your eyes, you will be able to hear many sounds. Sounds can be soft or loud, high or low, pleasant or unpleasant. You are going to describe different sounds. Fill in the table.

Sound source How loud (numbers from 1 to 10)

Pleasant Yes, No, Sometimes

A ticking clock

A growing plant

A piano

A drum

Clapping hands

Screaming


People whispering

A plane above your house

Can you trust your ears to decide how loud these sounds are? Which one is the loudest? Which one is the quietest? In this activity you will use the €Sense sound sensor to measure how loud sounds are. The unit for measuring sound is the decibel (dB). 10 dB means rustling, 50 dB means quiet conversation, 110 dB is a loud rock-group, 140 dB will seriously damage your ears. 1. Start the project ‘Exploring sound’ and the activity ‘How loud?’.

The sound sensor icon is already place on the €Sense panel. 2. For this activity you will use three alarm clocks (or buzzers). 3. Place the alarm clock 5 cm from the sound sensor. 4. Click the green Start button. Look at the graph. 5. Write down the recorded sound level of one alarm clock (how

many decibels) in the table below. 6. Now use two alarm clocks and start measurement again. 7. Do it once more for three alarm clocks.


Object Sound level in dB

one alarm clock

two alarm clocks

three alarm clocks

How is the sound level changing when the number of alarm clocks is growing?

8. Measure the sound level of different sound sources (see the table on the first page of this

activity).

Which object gives the loudest sound? _________________________________ Which object gives the quietest sound? _________________________________

9. Compare your results with your predictions from the observations.


Worksheet 2. Tell a story about sound When you listen to a radio or a tape recorder you listen to the sound. You hear the sound changing. How can you explain the changing of the sound? Turn on the radio and try to find a music station. Listen to the music for two minutes. Tell a story about the changing of the sound (write this story in your own words). In this activity the computer will help you to tell a story about the changing of the sound level. 1. Start the project ‘Exploring sound’ and the activity ‘Tell

a story about sound’. The sound sensor icon is already place on the €Sense panel.

2. Place the radio 10 cm from the sound sensor and turn it on. 3. Start the measurement by clicking the green Start button. 4. Slowly turn the volume control in one

direction, and then a bit faster in the other direction.

5. When your measurement is finished draw

the resulting and tell a story about this graph (when the sound level increases and when it decreases).

How can you see if the increase or decrease is fast or slow?

6. Now the volume changes will be made by your teacher (or from a tape).


7. First remove your data from the diagram by right clicking and selecting the Erase all Values option.

8. Listen carefully and make your prediction about the sound level. Draw a prediction graph

in the diagram pane on the screen. - right click the Diagram pane and select Sketch, - draw the prediction by dragging the mouse, - finish by right clicking the pane and selecting Stop Sketching.

9. Repeat the sound again and now record it by clicking the Start button. 10. Draw your prediction graph with a blue pen and your measurement graph with a red pen

in the diagram below.

Are there differences between the prediction and the measurement graphs? Explain them.


Worksheet 3. Make sound visible How are sounds made? You know that sounds may be soft or loud, high or low, pleasant or unpleasant. But all kinds of sounds are made in the same way. First you will observe how sounds are made. 1. You can see how sounds are made if you look at a drum.

Tiny pieces of paper may be put on the drum. What happens after the drum is hit? What makes the pieces move?

2. Hit the tuning fork with a small stick. You can hear the sound. Touch the ends of fork lightly with your fingers. What do you feel?

Now hit the tuning fork once more and put the ends of the fork into a glass with water. What happens to the water? Explain it.

3. There are many kinds of sounds, and all of them are

made by vibrations. Yet there are some differences in vibrations that can make one sound different from another one. Place a ruler over the edge of the table. Pull down the ruler and let it go. It is vibrating. It makes a sound. Investigate what happens when you place the ruler in different positions and let it vibrate. Describe the differences.

With the sound sensor connected to the computer you can make sound visible. 1. Start the project ‘Exploring sound’ and the

activity ‘Make sound visible’. The sound sensor icon is already place on the €Sense panel.

2. Place a tuning fork near the sound sensor. 3. Hit the tuning fork and click the green Start

button.


4. Look at the graph. You see peaks and valleys. (When it is necessary, zoom out the graph). You can see vibrations recorded with the sound sensor.

5. In the graph here one vibration is selected. The time of one vibration is called the period of vibrating. How frequently a vibration occurs is described by its frequency. The frequency and the period are the inverse of each other.

frequencyperiod

=1

The unit of frequency is Hertz (Hz). This indicates the number of vibrations per second. The frequency of 1 Hz means one vibration per second. With the help of the computer, scan the time for several vibrations and calculate the period of one vibration: Period of vibration = __________ s (remember, the computer shows time in milliseconds)

Frequency = ___________ Hz 6. Draw the result of your first measurement

with a blue pen. Take a tuning fork with another pitch. Strike the fork and start the measurement again. In the same diagram draw the new result with a red pen. What is the difference between these two graphs?

7. Remove the data from the graph (Erase

all Values option). Now hit the tuning fork softly and start the measurement again. Draw the graph with the blue pen. Then hit the fork harder and record the measurement once more. Draw the graph with the red pen. Explain differences between these two graphs.


Worksheet 4. Analysis of voice sounds You can hear when sounds are high or low, loud or soft. You can also hear different voice sounds. For example: say aaaaaa (from the word ‘are’), or say oooo (from word ‘or’), eeeee (from ‘see’) or other vowels. Keep your fingers against your throat and make a vowel sound. You can feel your throat vibrate. Now put earplugs in your ears and stand behind somebody. Keep your fingers pressed softly against his or her throat. Have your partner make different sounds while you investigate the feelings of the sounds. Can you feel if the sound is hard or soft? Yes/No Can you feel if the sound is high or low? Yes/No Can you feel the difference between different sounds? Yes/No In this activity the computer will help you to make your voice sounds visible. 1. Start the project ‘Exploring sound’ and the activity ‘Analysis of voice sounds’. The sound

sensor icon is already place on the €Sense panel. 2. You are going to record different voice sounds. Say AAAAA (from word ‘are’). Click the

green Start button while you are making the sound. 3. Look at the graph. Again you see peaks and valleys, but they are shaped differently now.

(When it is necessary zoom out the graph). Can you see that the same form comes back? 4. A tuning fork gives a pure tone, while the voice sounds give a more complicated vibration

pattern. Draw one vibration pattern of your measurement.

5. Now you will investigate vibrations of different vowels. Sing a high and then a low vowel

(keep the sound sensor at the same distance). Draw the resulting graphs


What is the difference between a high and a low vowel?

6. Now have different people (a boy and a girl) sing the same vowel. Draw graphs. BOY (MAN) GIRL (WOMAN)

Can you see differences between the graphs?


Worksheet 5. Analysis of instruments sounds Collect different instruments: guitar, violin, flute, xylophone, etc.

Listen to their sounds. Are these sounds more pleasant then the sound of a tuning fork or a school bell? Yes /No Tones of a tuning fork are pure tones with one frequency. Sounds of musical instruments usually consists of a number of tones with different frequencies. For people such a composition of tones sounds nicer than a pure tone. In this activity you will record the sounds of a guitar string and different tones from an organ pipe. The pitch of a string depends on string length, string thickness and string tension. A guitar has six strings with the same length and different thicknesses. All of a guitar’s tones are played on these strings. Higher tones can be played by making the vibrating part of the string shorter. You can shorten the vibrating part by pressing against the string with your fingers. 1. Start the project ‘Exploring sound’ and the activity ‘Analysis of instrument sounds’. The

sound sensor icon is already place on the €Sense panel. 2. Play a sound on the guitar string. At first, allow the entire length of the string to vibrate,

and then only two third of the length. To make the string shorter press against the string with your finger. What differences do you hear between these sounds?

3. Now repeat this procedure but record the guitar’s sound with the computer. Draw both

graphs. Explain differences.


4. Play a tone on an organ pipe. Do you know how the vibrations are made in an organ pipe?

5. Play a tone on an organ pipe. Click the

green Start button to start a measurement. Draw a graph.

Do you remember the graph of a tuning fork’s sound? What is the difference between these two graphs? Do you remember the graph of a voice’s sound? What is the difference between these two graphs?

6. Record sounds when you play soft or loud tones on the organ pipe. Draw the graphs.

Can you see differences between these two graphs?


Worksheet 6. How does sound travel? Robert Boyle, an English scientist who lived three hundred years ago, performed this experiment. Boyle hung a watch in a bottle. He could hear the watch ticking. Then he pumped much of the air out of the bottle. Now he could not hear the watch ticking. When he let air into the bottle again, he could hear the watch again. 1. Repeat Boyle’s experiment. Instead of the watch use an

alarm clock or an electric bell. Use a vacuum pump to remove air. What do you hear when there is no air inside? Allow air to re-fill the jar. What do you hear now?

2. Knock at one end of a table while your classmate listens with an ear against the other end

of the table. Can your classmate hear you knocking? Why?

Can you explain how the sound from next door gets to your ears?

What is necessary for sounds to travel?

If all air in the classroom were replaced with water, could you still hear?

Can you hear through walls?

In this activity you will use the sound sensor to find out what sound can travel through. 1. Start the project ‘Exploring sound’ and the activity ‘How does sound travel?’. The sound

sensor icon is already place on the €Sense panel. 2. Choose a noisy sound source.


3. Place €Sense sound sensor 20 cm from the sound source. Click the green Start button. Explain what the sensor detects.

4. Repeat the experiment but now place the sound source on one

side of the door. Close the door. Place €Sense on the other side of the door. Explain what the sensor detects now.

5. Find out if sound can travel through other materials. You can use

for example rubber pipe to sensor, glass, two cans with a string, balloon with water etc. Remember never to place the sound sensor in water. Keep the computer far away from water and wet hands.

Material Do sound travels through?

Wood

Glass

Water

..........

..........

..........

6. Describe once more what is necessary for sounds to travel.

7. Look at the picture and explain how you can hear

sound.


Worksheet 7. What is the best way to stop sound? Sometimes sounds from the traffic or the room next door can keep us from sleeping. Sounds can also distract us from what we are doing. Do you know how you can stop sound? Can sounds be dangerous to you? Yes/No/Sometimes When can sound be dangerous? How can people protect themselves against loud noises? In this activity you will use the sound sensor to find the best way to stop sound. 1. Start a project ‘Exploring sound’ and activity ‘What is the best way to stop sound?’. The

sound sensor icon is already place on the €Sense panel. 2. Place the sound source inside a shoe box and start a measurement by clicking the green

Start button. 3. This will be your control measurement. You will compare all other measurement to this

one. Be very silent during the measurements.


4. Cover the sound maker with different materials (like cotton wool, different fabrics, egg cartons, newspaper etc) and each time record the sound which is coming to the sound sensor. Record the results of your measurements in the table below.

Insulators How much sound Amplitude in %

Without insulator

..................

....................

......................

....................

.....................

5. What happens when you use insulating materials?

6. Which material stops sound most effectively?

7. Which material is the worst at stopping sound?

8. Get two sound sources: one should make a high-pitched sound and the other should

make a lower sound. Which kind of sound (high or low) is easier to stop?


Worksheet 9. Does sound get more quiet further away? A plane is flying above your house. At first you hear a quiet sound and then it gets louder but finally it becomes quiet. First the plane is far away and then it comes closer to you and then at the end it is going farther away. Below, you see the graph of the sound level coming from the plane.

Describe the graph. After how many seconds is the sound the strongest? Explain the difference of the graph from 0 to 20 s and from 20 to 60 s. In this activity you are going to see what happens to the sound level when the distance between the sound source and the sound sensor is growing. You will measure the sound from an alarm clock (or another noisemaker). 1. Start the project ‘Exploring sound’ and the activity ‘Does sound get quieter further away?’

The sound sensor icon is already place on the €Sense panel. 2. Place the alarm clock near the sensor. You are going to move the clock away from the

sensor as far as you can, and then bring it back to the sensor. 3. First you will try to predict what will happen to the sound level in such an experiment.

Choose the Sketch option and drawn your prediction.


4. When you are ready, click the green Start button and move the clock away from and then back toward the sensor.

5. Draw your prediction with a blue pen

and your measurement with a red pen in the right diagram. What is the difference between your prediction and your measurement?

6. Repeat your measurement but move the clock faster this time. 7. The distance between the sensor and the sound source becomes larger. Explain what

happens to the sound level.

Date post:	26-Mar-2015
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