Post on 21-Jan-2016
transcript
Created by AMSTI trainersRevised by Stacy Chang
Presenter: Stacy ChangAMSTI Science Specialist
changsl@uab.edu
Electric Circuits
• The• Learning
• Cycle
• “The 5 E’s” • of an inquiry-based lesson
• Initiate
• Apply • Clarify
• Question
• Evaluate
• Question/Problem/Purpose• Hypothesis• Procedure/Planning• Results/Data/Observations• Conclusion/What Have You
Learned?• Next Step/New Question
Science Notebook Components
4
• Overview and Objectives• Background Information• Materials• Preparation• Procedure• Final Activity• Extension• Assessment
Lesson Outline
Lesson 1-
Thinking About Electricity and Its Properties
Electric CircuitsWhat do KNOW about electricity?
What do you WONDER about electricity?
KNOW WONDER
DateLesson 1: Thinking about Electricity and Its Properties
Brainstorm 3 or more safety rules about electricity and discuss them
with your teammates.
Illustrate one of your rules.
Electricity Safety Rules
1. Never use the electricity from wall outlets for experiments.
2. Never play with wall outlets or wall switches.
3. Do not use an electric device in the bathtub, in the shower, or
in a swimming pool. Electricity and water do not mix!
4. Do not touch a switch or electric device when your hands are wet.
5. Stay away from power lines.
6. Do not fly a kite or model airplane near a power line.
7. Never use a broken cord, plug, or appliance.
Electricity Safety Rules
Extensions
*Make a collage of pictures illustrating all the ways that they use electricity at home. Make a bulletin board to present findings.
*Ask students to imagine what life would be like without electricity. Write an expository paper that explains how everyday activities would be different.
Lesson 2-
What Can Electricity Do?
DateLesson 2: What Can Electricity Do?
Question: How can we light a bulb?
Hypothesis: IF we wanted to light a bulb, THEN…
Lesson 2
Materials Manager:
Please pick up one storage box from the distribution center.
Get:
1. One D - cell battery
2. One bulb
3. One wire
Lesson 2
Can you make the bulb light??
Plan: Create a plan to connect the materials to get the bulb to light.
Observations: Illustrate the different ways the bulb would light on and the ways the bulb would not light on.
Bulb lights ON Bulb Does NOT light
TG p. 9
NOTE:
If the D-cell or the wire becomes warm, you probably have created what is called a short circuit. A short circuit is created when the two ends of the D-cell are connected directly through the wire. Do not leave the D-cell connected this way or it will become worn out. Then it will not longer light the bulb.
Short Circuit
Lesson 2
Conclusion: What did you learn from the investigation?
Key Concepts: Electricity must be able to move from one end of the battery to the other end to create a complete circuit.
VOCABULARY WORDS
Battery- A device that can produce an electric current as a result of chemical change in it
Draw a picture of a battery.
Voltage- the measure of electrical pressure
Wire- A metal strand used to connect electrical devices in a circuit
Reflection/ Next Steps:
Lesson 3-
A Closer Look At Circuits
Can anyone show us exactly where the wire needs to touch the bulb to make it light?
Date
Lesson 3: A Closer Look at Circuits
Question: Which arrangements do you think will make the bulb light? Which arrangements won’t?
Hypothesis: State your prediction by writing “On” or “Off” under each picture in PEN. –
-
On On On
Off Off Either
Off Off On
Conclusion:
Key Idea: For the bulb to light, a connection must be made to the positive and negative ends of the battery as well as to the side and base of the bulb.
Electric Current- A flow of electric charge through something
Reflection/ Next Steps:
Lesson 4-
What Is Inside a Light Bulb?
Inside a Real Light Bulb
Incandescent Light Bulb
When you turn on a light bulb, electricity flows through the filament. As the filament heats up it produces light.
The color of the light depends on the temperature of the filament.
What’s Inside a Light Bulb? QuickTime Video
Date Lesson 4: What’s Is Inside a Light Bulb?
Question: What is inside a light bulb? Color code
TG 22
1. Filament
2. Support Wires
3.Glass Support
4. Wire attachment point
5. Support Wires
6. Ceramic insulator
7. Metal tip
Investigation Question: How many D-cell batteries do you think it will take to light a household light bulb?
Hypothesis: If we try to light a household light bulb with D cell batteries, then I think it will take ________because____________________________.
Class Data:
#of Batteries Guessed Frequency
Observations: Write and draw what you observed.
Reflection/ Next Steps:
Plan:
Lesson 5-
Building a Circuit
Hypothesis ResultHypothesis ResultHypothesis ResultHypothesis ResultHypothesis ResultHypothesis ResultOff
DateLesson 5: Building a Circuit
Question: Which circuit connection will light the bulb?
Activity Sheet 2 TG p. 30
On
OnOn
On
Off
Question: What could we use to make circuit building easier?
THINK AND WONDER
The devices on the ends are used to hold wires and are called Fahnestock clips.
• Battery
Holder
• Bulb Socket
3. Attaching a wire to the Fahnestock clips
-
Try to build a complete circuit using our new materials!
In your science notebook:
Draw your completed circuit that includes the battery holder, battery, wires, bulb, and bulb socket.
• What are the crucial connections and elements necessary to make the bulb light?
• What is happening in this circuit?
Key Concepts: An electric circuit is a continuous path for electricity to travel in going from one end of the battery, through wires (including wires in the bulb), back to the other end of the battery.
Circuit- A system that connects electrical devices so that they will operate
Open Circuit vs. Closed Circuit
Lesson 6-
What’s Wrong with the Circuit?
Activity Sheet 3 TG p. 37
Lesson 6: What’s Wrong with the Circuit?
got problems
Work with problem circuit testers.Discuss problem-solving techniques to fix a circuit tester that doesn’t work. TG p. 35-36
1st-First, look at the wire connections to make sure they are secured tightly. Do this by wiggling them gently to check that they are not loose. Test the circuit (by touching the end wires together) again to see if the bulb lights now.
2nd-Look at the battery and make sure it is in its holder tightly and that the ends of the battery are touching the battery holder. Test it again (by touching the end wires) to see if the bulb lights.
3rd-Next, look at the bulb and make sure it is screwed securely into the socket. (But not too much. Students often keep turning the bulb more than is necessary to make contact.) Test the circuit again to see if the bulb will light.
Problem-Solving Techniques To fix a circuit tester that doesn’t work TG p. 35-36
4th-If it still doesn’t work, check the battery and the bulb separately by first taking out the bulb and lighting it using one wire (as in Lesson 2) and a good battery.
5th-If the bulb is good, the next step it to test the battery. Take the battery from the holder and test is again by using the one-wire technique (as mentioned next to the first item) with a bulb that you know is good.
6th-At this point, if you have established that the bulb and the battery are good, put the system back together. If it still doesn’t work, you know there must be a loose connection somewhere in the system.
Lesson 7-
Conductors and Insulators
Can electricity flow through any material?
Look at the picture below. What does it mean if the bulb lights when you touch the wire to the ends of the paper clip?
Do you think replacing the paper clip with a piece of chalk will make the bulb light up?
Can electricity flow through this
material?
HYPOTHESIS
ACTUAL RESULTS
(Conductor or Insulator?)YES NO
1 Golf Tee
2 Straw
3 Brass Screw
4 Paper Clip
5 Aluminum Screen
6 Plastic Screen
7 Chalk
Hypothesize. Check YES or NO.
CHECK TO MAKE SURE YOUR CIRCUIT TESTER IS WORKING.
TEST YOUR HYPOTHESES!
Can electricity flow through this
material?
HYPOTHESIS
ACTUAL RESULTS
(Conductor or Insulator?)YES NO
1 Golf Tee
2 Straw
3 Brass Screw
4 Paper Clip
5 Aluminum Screen
6 Plastic Screen
7 Chalk
Insulator
Insulator
Insulator
Conductor
Conductor
Conductor
Insulator
8 Pencil
9 Brass Paper Fastener (brad)
10 Finishing Nail
11 Aluminum Nail (flat head)
12 Marble
13 Pipe Cleaner
14 Copper Wire
15 Aluminum Rod
Can electricity flow through this
material?
HYPOTHESIS
ACTUAL RESULTS
(Conductor or Insulator?)YES NO
Lead to lead-conductor Wood- Insulator
InsulatorMetal to metal -conductor Brush- Insulator
Conductor
Conductor
Conductor
Conductor
Conductor
1. Analyze your results. What types of materials were able to conduct electricity?
2. What types of materials were NOT able to conduct electricity?
3. When electricity moves easily through an object, we call it a ______________________. Materials that conduct electricity are used to make wires for electrical circuits.
4. When electricity does not move easily through an object, we call it an ____________________. Materials that do not conduct electricity are helpful, too.
5. Evaluate how these materials can be helpful to us.
Lesson 8-
Making a Filament
What happens when you turn a lamp on?
A wire inside the light bulb glows.
This wire is called a filament.
During this lesson, you will make a device that is a lot like a light bulb.
You will use a special kind of wire to make a filament for your light bulb.
SAFETY TIPS:
• We will work in pairs for this lesson.
• The thin nichrome wire can cause small cuts on fingers if it is pulled too hard.
• The nichrome wire gets hot when it glows. Do NOT touch it, even if it falls off, until it has cooled.
• The hot nichrome wire can ignite flammable materials, such as paper.
Divide you lump of clay into two pieces. Push one part down on your desk.
Take two of the wires you have been using to make circuits (DO NOT get clay on the end of the wires) put them on the clay about ½ inches apart, with the middle part of the wire pushed into the clay. Place the remaining clay over the wires so that it supports the wires.
-
Take the strand of Nichrome wire and wrap it around the ends of the hook-up wire. BE CAREFUL: The Nichrome wire is thin and can cut the ends of your fingers if you pull it too hard. Wrap the wire snugly around the ends of the hook-up wire. Have about ½ inch of
wire between the ends of the hook-up wire.
-
Arrange two batteries so they can be connected to the other end of the wires. Arrange the wires so that nothing is touching the Nichrome wire.
Connect the batteries as shown.
In your science notebook record the following question: What do you think will happen to the Nichrome wire?
-
Question: What do you think will happen to the Nichrome wire in the filament?
Hypothesis: If we make a model light bulb then I think the Nichrome wire will______, because _____.
Observations: Draw and describe how we made the filament.
If your “bulb” doesn’t work, check the following:
• Are the connections good everywhere?
• Are the ends of the wires clean and free from oils? (CLAY)
• Are the batteries in the same direction?
• Is the Nichrome wire no more than ½ inch between the ends of the hook-up wire?
Conclusion:
Review: Filament- A fine wire that becomes hot and produces light when an electric current passes through it.
Nichrome wire- wire made of nickel and chromium
Next Step: What do you think the glass part of the bulb does? Does it act as a conductor or insulator? How could we find out?
Reflection:
A Yummy Extension!
Lesson 9-
Hidden Circuits
Circuit Box Puzzles
How could you use a circuittester to find hidden circuits?
How many different possibilities are there?
Prep Time:See TG Materials
Management and Safety p. 14-15
In your science notebook :
Record Circuit
Combinations for Each Box
Lesson 10-
Deciphering a Secret Language
Question: How can we
communicate various circuits to
someone using a drawing? How do
electrical engineers communicate
their designs?
Electrical engineers use symbols to draw circuit diagrams of circuits they make.
-
A Secret Language
Let’s use the symbols to draw a circuit diagram of this circuit.
1.With your partner, make a circuit with one battery, two bulbs, and whatever wires you need. Draw a circuit diagram using the symbols.
Example:
-
Using the “Secret Language”
Place your circuits inside your box and
have another team make the circuit using ONLY your circuit diagram.
Does it match your circuit?
If it is not correct, do not erase. Keep working
on new circuit diagrams. Save all your efforts. Later you can go back and see how much you have learned.
Key Concept: Electrical engineers use symbols to draw circuit diagrams of circuits they make.
Circuit Diagram- A drawing that uses symbols to show how the parts of an electric circuit are connected.
Next Step/Extension: Assume you have two batteries and two bulbs to work with. Draw a circuit diagram that includes them in one circuit.
Make the circuit.
Lesson 11-
Exploring Series & Parallel Circuits
Look at the pictures below of two differentcircuit diagrams. What’s the difference?
Question: Which bulb do you think will burnbrighter? Which bulb do you think will burnlonger? Why?
Batteries in Series
Batteriesin Parallel
Batteries in Series & Parallel
Investigate! Use a simple circuit with one bulb and one battery as the standard. Compare other bulbs to this one and classify them as dimmer, about the same, or brighter than “the standard.” Record your observations in your NB.
Standard
Batteries in Series & Parallel
Batteries in Series
Batteriesin Parallel
A. Batteries in Series
• Electricity only has ONE path to travel around the circuit.
• Voltage is increased.
• Burns brighter, but battery drains quicker
B. Batteries in Parallel
• Electricity travels along MORE THAN ONE path around the circuit.
• Each bulb burns the same as with one battery, but the battery will last longer.
Batteries in Series & Parallel
Now, look at the pictures below.
Question: Which will burn brighter? Whichwill burn longer? Why?
Bulbs in Series
Bulbsin Parallel
Bulbs in Series & Parallel
Investigate! Compare bulbs in series and bulbs in parallel circuits.
Classify them as dimmer, about the same, or brighter than “the standard.” Record your observations in your NB.
Use a standard to compare.
Bulbs in Series & Parallel
Bulbs in Parallel
Bulbs in Series
A. Bulbs in Series• Burn in uniform
brightness, but dimmer than the standard circuit.
• Unscrew one bulb, both will go out.
• Each bulb- dependent path
B. Bulbs in Parallel• Each bulb burns the
same as the standard, so the battery will drain faster.
• Unscrew one bulb, the other will not go out.
• Each bulb-independent paths.
Bulbs in Series & Parallel
VOCABULARY
Series circuit- An electric circuit in which the components are in a single path so that they current has only ONE closed path to follow
Parallel circuit- An electric circuit in which the components are connected so that the current can follow more than one closed path
Challenge:Set up an experiment to see which circuit will burn longer; the series circuit, the parallel circuit, or the standard circuit.
Make a prediction: Which one will burn the longest?
After all three bulbs have gotten dim enough that all agree are “burned out” discuss the results. What do you think caused the bulbs to go out? How could you check these ideas?
Lesson 12-
Learning About Switches
Lesson 12- Learning about Switches
Question: What are necessary/ useful parts of a flashlight?
• A power source
• A light
• Wires (conductors)
• A switch
• Portable
(battery)
(bulb)
Where have you seen switches?
WallHair dryer
Make a switch and draw the symbol for it.
DESIGN A PLAN FOR A FLASHLIGHT
Lesson 13-
Constructing a Flashlight
Question: How can we create a working flashlight?
Create a flashlight!
Draw your flashlight and circuit diagram that is in your flashlight.
Electric CircuitsBrainpop Video Clip
Lesson 14-
Working with a Diode
Materials Manager:
For each pair of students:
TWO storage boxes
One simple diode
Two Fahnestock clips
1 paper clip switch -
Note: you may have to take apart your flashlight so you can use the materials.
Make a circuit tester using two batteries in series and one bulb. Make sure that the circuit works by touching the end wires together.
Observe your simple diode. Test it with your circuit tester by touching the wires to each end of the diode.
????????What happens?????????
What do you think might be the reason that some bulbs light and others do not?
Reverse your diode to see what happens.
Can you include the paper clip switch into the circuit with the diode attached so the light comes on/off?
Record your observations in your Science
Notebook.
Now, put your paper switch and the diode into the circuit. Use two Fahnestock clips to connect the wires to the diode as shown here. Make sure the switch turns the light on and off.
3. Look at your diode. Notice that there is a colored band on ONE end of the diode.
Diode
Symbol
In your Science Notebook draw the symbol for a diode. Draw a circuit diagram that includes your circuit tester, the switch, and the diode.
The diode is always pointed in the same direction in relation to the battery when the bulb lights. The direction of the diode is determined by its circular marking.
Diodes will pass electricity in ONE direction, in the same way a one-way street controls traffic.
How does that compare to the wire we have been using?
Where do you think you might find diodes?
Let’s observe your circuit diagrams:
4. What have you learned about diodes?
Key Concepts:
• A diode is a semiconductor device that allows current to flow in one direction, but not in the other.
• Diodes are used by engineers and technicians who make radios, televisions, and other electronic devices.
Lesson 15-
Planning to Wire a House
Teams of 2 or 4
Draw a plan for your house (or a room). Use symbols, labels, and colors in your design.
You may want to plan on bringing some decorative items from home to incorporate in your house or room.
Question: How can we wire a house (or room)?
Things to Consider:
Should you use only one D cell battery and one light for each room?
Should you use two D cells as a power source, and have them placed “outside” the house, similar to the way power is sent from the electric company to “real” houses?
How bright do you want the lights to be?
Where will you place the switches?
Where will the wires be placed?
Can you add a door bell or ceiling fan?
Lesson 16-
Wiring and Lighting the House
Think and Wonder
• Like a construction crew, you and your teammates will construct a house and wire it so that it will have light. You will work together to solve whatever problems come up.
Find Out for Yourself
• Use the plans you created in the previous lesson. Work together with your team to wire and light the room.
• Use the masking tape to fasten the wires to the walls and to attach the switches to the walls.
Trouble shoot if needed
Compare Before and After
• In your Science Notebook, make a wiring diagram of the model house. Compare the diagram of what you actually did with your original plans. What changes did you make? Why did you make those changes?
Extensions• Groups should be allowed to present final
projects to class or other audience.• Challenge students to consider one room
with two doors and one light. Put a switch by each door and wire the room so that either light switch can be used to turn the light on/off (see figure 16-1).
• Invite an electrician or someone from the power company to speak to the class.
At the end of lesson 16 (or throughout the unit), add to the KWL chart.
LEARNED
Conductor or Insulator?
1. straw2. wooden golf tee 3. brass screw 4. aluminum screening 5. marble 6. pipe cleaner 7. masking tape
Guess the vocabulary!1. a path that allows the flow of electricity 2. the measure of electrical pressure 3. the actual flow of electricity 4. opposition to the flow of electricity
Series or Parallel?
What’s happening?
What does the symbolrepresent?