Applying the Scientific Method • B1.1 Generate hypotheses on the basis of credible, accurate, and relevant sources of scientific information. • B1.4 Design a scientific investigation with appropriate methods of control to test a hypothesis (including independent and dependent variables), and evaluate the designs of sample investigations. • B1.5 Organize and interpret the data from a controlled scientific investigation by using mathematics (including formulas and dimensional analysis), graphs, models, and/or technology. • B1.6 Evaluate the results of a controlled scientific investigation in terms of whether they refute or verify the hypothesis. • B1.7 Evaluate a technological design or product on the basis of designated criteria (including cost, time, and materials). • B1.8 Compare the processes of scientific investigation and technological design.
Transcript
Applying the Scientific Method• B1.1 Generate hypotheses on the basis of credible, accurate,
and relevant sources of scientific information. • B1.4 Design a scientific investigation with appropriate
methods of control to test a hypothesis (including independent and dependent variables), and evaluate the designs of sample investigations.
• B1.5 Organize and interpret the data from a controlled scientific investigation by using mathematics (including formulas and dimensional analysis), graphs, models, and/or technology.
• B1.6 Evaluate the results of a controlled scientific investigation in terms of whether they refute or verify the hypothesis.
• B1.7 Evaluate a technological design or product on the basis of designated criteria (including cost, time, and materials).
• B1.8 Compare the processes of scientific investigation and technological design.
Hypothesis• a reasonable explanation of an
observation or experimental result
• a possible answer to a scientific question that can be tested.
• may or may not be supported by the experimental results.
• stated in terms of an independent and a dependent variable—or a “cause-effect relationship.”
Examples of hypotheses
*If a leaf has a greater surface area, then the rate at which it produces oxygen may increase.
*If a cell has a higher surface area, diffusion occurs faster.
*At warmer temperatures, mold will grow faster on bread.
Practice on your own
• Write some examples of Hypothesis.
If ____________, then ____________.
Format of Scientific Method
• http://sciencespot.net/Media/indinvest.pdf
this corresponds to the next slides that we can have them fill in as we go along……
Question• Stating the purpose in the form of a
testable question or problem statement
• Researching information related to the investigation
Hypothesis• testable educated guess
• predicts the relationship between an independent and dependent variable
• Use credible, accurate and relevant sources
Procedure1. Plan for independent and dependent
variables with repeated trials
2. Plan for factors that should be held constant (controlled variables)
3. Plan for a control group to set up as a basis of comparison
4. Set up the sequence of steps to be followed
5. List materials
DataRecording, organizing and
analyzing data:
• charts
• graphs
IndependentVariable
DependentVariable Independent
Variable
De
pen
den
tV
aria
ble
Conclusion/AnalysisConclusion statement that experiment
supported or did not support the hypothesis.
Discussion of results to explain why hypothesis supported or not.
Conclusion/ AnalysisResults of an experiment cannot prove that a hypothesis is correct. Rather, the results support or do not support the hypothesis
• If the data is consistent with the prediction in the hypothesis, the hypothesis is supported.
• If the data is not consistent with the prediction in the hypothesis, the hypothesis is refuted.
Do You Remember DRY- MIX?
D = Dependent VariableR = Responds toY = Y-axis
M = ManipulatedI = Independent VariableX = X-axis
Variables in Science Experiments
What makes an experiment
“fair”?
Variables• A variable is something that is changed
• A constant, or control, is something that does not change
Science Experiments Use…
• Independent Variable: the one factor that is changed by the person doing the experiment
•Dependent Variable: the factor which is measured in the experiment
•Constants: all the factors that stay the same in an experiment
(copy these terms to Procedure box)
A birdie example…Imagine you want to see what color of
bird feeders your local birds preferred.
Red? Blue? Green?
Our Constants and Variables
• Independent Variable: color of the feeders
• Dependent Variable: amount of seed eaten
• Constants: everything else that is kept the same, for example:
– the location of the feeders
– the kind of feeder used
– putting the feeders out at the same time
Our Experimental Design
Constants
Location of feedersKind of seedType of feeder
IndependentVariable
Red Blue Green
DependentVariable
Amount of Seed Eaten
Amount of Seed Eaten
Amount of Seed Eaten
If everything except the independent variable is held
constant, we can say:
The experiment is FAIR.
(ONLY the independent variable can change!)
Why is it important to only change the
independent variable?
If you don’t…
If you measure a change in the dependent variable, you won’t know whether it is the independent variable that is causing the change.
Sam wants to know if birds prefer one color of feeder to another. He makes three feeders out of 2-liter bottles and paints one red, one blue, and one green. He fills the feeders with the same amount of sunflower seed, and plans to keep the feeders out for one week before measuring how much seed is eaten out of each. On Tuesday, he puts each of the feeders in his back yard: the red feeder in a large dead tree, the blue feeder he sits on the doghouse, and the green one he puts in a small bushy tree.
Scenario #1
Is Sam’s experiment fair?
YES? NO?
NO! It isn’t fair since the locations of the feeders were very different!
Maria wants to know if birds prefer one color of feeder to another. She makes three feeders out of 2-liter bottles and paints one red, one blue, and one green. She fills each of the feeders with the same amount of mixed birdseed, and plans to keep the feeders out for 10 days before measuring how much seed is eaten from each feeder. She puts each of the feeders in the school courtyard in a small tree, hanging each at the same height.
Scenario #2
Is Maria’s experiment fair?YES? NO?
YES! It seems fair since Maria only changed the feeder color!
Jessie wants to know if birds prefer one color of feeder to another. She makes three feeders out of 2-liter bottles and paints one red, one blue, and one green. She fills the each of the feeders with sunflower seed. She plans to leave each feeder out for 2 days and then measure the amount of seed that the birds ate. She has one hook in her backyard the she plans to hang each of the feeders on. She puts the red feeder out on Tuesday and measures the seed 2 days later, the green feeder doesn’t go out until Saturday since it was very snowy, but she is able to measure the seed 2 days later. The weather turned rainy, but she needs to finish her experiment, so blue feeder goes out on Monday and is measured 2 days later.
Scenario #3
Is Jessie’s experiment fair?YES? NO?
NO! It isn’t fair since the feeders are not out at the same time, and we know that the weather was quite different each time. Perhaps the number and kind of birds that visited during the weeks were different due to the weather.
What do you think?Terry loves birds and wants to see as
many as she can in her yard. She wants to know whether she is wasting money buying an expensive mixed seed, when a cheaper brand just arrived at her local store. She wonders… will the expensive seed attract more birds to her back yard?
How would you advise her to find out if the expensive seed is better?
Terry’s Experimental Design
IndependentVariable ?
DependentVariable
?
Constants ?
Terry’s Experimental Design
IndependentVariable
Kind of seed: Expensive Cheap
DependentVariable
Number (and perhaps kinds) of birds that visit
Constants
• Location of feeders•Type of feeder
•Way she measures the amount of seed eaten and the way she counts birds
What experiments are you planning?
• What are your variables?
• How will you keep your experiment fair?
Activity 2 – Identify the Controls and Variables Scenario #1
Smithers thinks that a special juice will increase the productivity of workers. He creates two groups of 50 workers each and assigns each group the same task (in this case, they're supposed to staple a set of papers). Group A is given the special juice to drink while they work. Group B is not given the special juice. After an hour, Smithers counts how many stacks of papers each group has made. Group A made 1,587 stacks, Group B made 2,113 stacks.
Identify the:1. Control Group
2. Independent Variable
3. Dependent Variable
4. What should Smithers' conclusion be?
5. How could this experiment be improved?
6. What was the initial observation?
Activity 2 – Identify the Controls and Variables
Scenario #2Homer notices that his shower is covered in a strange green slime. His friend Barney tells him that coconut juice will get rid of the green slime. Homer decides to check this this out by spraying half of the shower with coconut juice. He sprays the other half of the shower with water. After 3 days of "treatment" there is no change in the appearance of the green slime on either side of the shower.
Identify the:7. Control Group
8. Independent Variable
9. Dependent Variable
10. What should Homer's conclusion be?
Activity 2 – Identify the Controls and Variables
Scenario #3Bart believes that mice exposed to radiowaves will become extra strong (maybe he's been reading too much Radioactive Man). He decides to perform this experiment by placing 10 mice near a radio for 5 hours. He compared these 10 mice to another 10 mice that had not been exposed. His test consisted of a heavy block of wood that blocked the mouse food. he found that 8 out of 10 of the radiowaved mice were able to push the block away. 7 out of 10 of the other mice were able to do the same.
Identify the:11. Control Group
12. Independent Variable
13. Dependent Variable
14. What should Bart's conclusion be?
15. How could Bart's experiment be improved?
Activity 2 – Identify the Controls and Variables
Scenario #4Krusty was told that a certain itching powder was the newest best thing on the market, it even claims to cause 50% longer lasting itches. Interested in this product, he buys the itching powder and compares it to his usual product. One test subject (A) is sprinkled with the original itching powder, and another test subject (B) was sprinkled with the Experimental itching powder. Subject A reported having itches for 30 minutes. Subject B reported to have itches for 45 minutes.
Identify the:16. Control Group
17. Independent Variable
18. Dependent Variable
19. Explain whether the data supports the advertisements claims about its product.
Activity 2 – Identify the Controls and Variables
Scenario #5Lisa is working on a science project. Her task is to answer the question: "Does Rogooti (which is a commercial hair product) affect the speed of hair growth". Her family is willing to volunteer for the experiment.
Identify the:20. Describe how Lisa would perform this experiment. Identify the control group, and the independent and dependent variables in your description.
The shape of a graph can show the relationship between the variables
in the hypothesis.
The shape of a graph can show the relationship between the variables
• Homework: Lessons 1 – 6 walks through scientific method
Activity 4
Gummy bear lab
Scientific Models• are descriptions of how phenomena
occur and how data or events are related.
• are used to represent a concept or system so that the concept may be more easily understood and predictions can be made.
• Models may change over time as scientific knowledge advances.
Technology
• tools/machines or processes that can be used to develop better understanding of the science concepts studied.
• We can organize and analyze data using technology such as graphing calculators or computers.
Technological designs• Are produced by the application of
scientific knowledge to meet specific needs of humans.
There are four stages of technological design:
– Problem identification
– Solution design (a process or a product)
– Implementation
– Evaluation
Technological designs
– Cost effectiveness or lowest cost for production;
– Time effectiveness or the least amount of time required for production, and
– Materials that meet specific criteria, such as:
– Solves the problem
– Reasonably priced
– Availability
– Durability
– Not harmful to users or to the environment
– Qualities matching requirements for product or solution
– Manufacturing process matches characteristics of the material
– Understand that benefits need to exceed the risk.
– There are tradeoffs among the various criteria. For example, the best material for a specific purpose may be too expensive.
•Common requirements within the solution design stage of all technological designs or products include:
Notes
1. Science is a process of inquiry that searches for relationships that explain and predict the physical, living and designed world.
2. Technology is the application of scientific discoveries to meet human needs and goals through the development of products and processes.
Notes (cont)3. The processes of scientific investigation
are followed to determine the relationship between an independent and dependent variable described by a hypothesis.
4. The processes of technological design
are followed to design products or processes to meet specified needs. The results of technological designs can advance standard of living in societies.
5. In general, the field of engineering is responsible for technological designs or products by applying science to make products or design processes that meet specific needs of mankind.
