1. Designing Experiments Using the Scientific Method
Lesson 1
Designing Experiments Using the Scientific Method
Key Terms
Scientific Method
Independent Variable
Hypothesis
Dependent Variable
Experiment
Control Group
Data
Experimental Group
Conclusion
Trial
Procedure
Experimental Error
Variable
Bias
Notice the color of our key terms.

2. process
answers
steps
problem
question
organized
educated guess
information
Identify the problem
Form a Hypothesis
Create an Experiment
Perform an Experiment
Analyze the Data
Modify the Experiment
Conclusion

3. Let’s use some of our “key words” in an investigation.
I want to know if warmer temps. cause robin eggs to hatch faster?
First, our procedure.
(Step by step plan)
Robins’ Eggs Experiment
Variable
Control Group
Experimental Group 4 4
Number of eggs
Temperature
85 degrees
97 degrees
70%
70%
Humidity
Lighting
Low Light
Low Light
Variable- Factor that affects results of an experiment.
There are 2 kinds of variables.
1. Independent Variable-Factor I change to find out what will happen. Here it is temp.
2. Dependent Variable-Variable affected by changes in independent variable. Here it is
how long it takes the eggs to hatch.
Control Group-Group used for comparison. All variables controlled by me.
Experimental Group-Group exposed to changes in independent variable. Can you see
what I changed in this group?
Every time we repeat this experiment it is called a Trial.

4. Mythbusters using the Scientific Method!

5. scientists
observations
experiments
hypotheses
conclusions
results

6. Why was my number different than yours!?
Maybe it was experimental error?
Human Error
True value of measurement vs. Measured value
Sunflower Seed
6 mm
7mm
l___________l
l___________l
Your lab partner measured
the same seed at 7mm.
You measured 6mm.
Actual measurement was 6.5 mm. Why?

7. But I want my hypothesis to be right!
This kind of thinking can cause
bias.
Bias is a wish or expectation that
your experiment will lead to a certain
conclusion.
Let’s watch a clip to better
understand bias >

8. in a nearby pond. The farmer measures the amount of fertilizer in the
Discussion Questions
1. What data would lead scientists to accept the hypothesis in the experiment with the robins’ eggs? What results might lead them to reject the hypothesis? What other variables might affect the results?
2. A farmer believes that fertilizer runoff from a farm is killing the fish
in a nearby pond. The farmer measures the amount of fertilizer in the
pond each week and counts the number of dead fish. The measurements
indicate that, as the fertilizer concentration increases, the number of
dead fish increases. Can the farmer confidently conclude that it must
be fertilizer from the farm that is killing the fish? Why or why not?

9. Quiz Time! + +

10. Quiz Time! + +