1. What makes a question testable?
Essential Question
 What makes a question testable?
How do we find answers with scientifically reliable methods?

2. The Scientific Method & Experimental Design

3. In science, we only deal with facts
From observations
From experiments

4. The scientific method is a systematic way to help us find answers to the questions we have
There are 5 main steps

5. Observation and Research
Step 1
Observation and Research
See
Hear
Smell
Taste
Feel
For example:
I got home from school and I smelled gas when I walked in my house.

6. Step 1, continued Observations lead to questions
For example: Why does it smell like gas in my house?

7. Step 2
Form a hypothesis
a statement that predicts a relationship between cause and effect
A good hypothesis will follow the “if…then” format
Example: If I smell gas, then there is a gas leak.

8. Step 2, continued A hypothesis must be testable.
For example: I can collect data (do a test) to see if there is a gas leak.
But if I said, If I wear perfume, then I will smell good
I can’t test that

9. Step 3 Gather data/experiment
You can do this by designing an experiment, making more observations, taking measurements, etc.

10. Step 4
Data Analysis
Look at the facts you collected and see if they mean anything or give you any answers.
This is one of the most important steps!

11. Step 5 Conclusion – Do you accept your hypothesis or reject it?
If your data supports the hypothesis, you accept it
If your data does not support it (even a tiny bit), you reject it and start over

12. Let’s try it Step 1 Observation
The light doesn’t come on when I flip the switch.
That leads to a question: Why?

13. Step 2
Hypothesis
Use the “if…then” formula
If the light doesn’t come on, then
The bulb is burned out
The lamp is unplugged
The power is out
Finish the hypothesis on your paper

14. What experiment or data would you do or gather?
Step 3 - Experiment
You can check the bulb or the plug, try other switches in the house, etc. You are gathering data to help you answer your question.
What experiment or data would you do or gather?

15. Step 4
Analyze Data
Look at the facts you gathered to see if they support your hypothesis or not
Let’s say your hypothesis was that the power was out and you found that none of the switches worked. That would support your hypothesis

16. Step 5
Conclusion
Accept the hypothesis
But if you found that the other switches did work, reject the hypothesis and make a new one

17. Experimental Design
When scientists design experiments, they must follow certain rules.
A good experimental design has:
One independent variable
A dependent variable
A control group

18. Experiments
The independent variable is the thing you change in the experiment

19. Experiments
The dependent variable is the thing you measure during the experiment

20. Experiments The control group is for comparison
You do not experiment on the control group

21. Let’s practice – first watch me
So what is the INDEPENDENT VARIABLE? (the one thing that is different?)
So what is the DEPENDENT VARIABLE? (the thing that is being measured?)
Samantha wanted to know if fish breathe faster in warm water. She set up three tanks:
1 with fish in cold water (10 degrees C)
1 with fish in room temperature water (20 degrees C)
1 with fish in warm water (30 degrees C)
Then she counted how many breathes they took for 1 minute
The one with normal (room temperature) water
The number of breaths
The temperature of the water
Which tank is the control tank?

22. Let’s practice What will be my independent variable?
The type of fertilizer
What will be my dependent variable?
The number of strawberries on each plant.
What will be my control group?
Strawberry plants with no fertilizer
I want to know what kind of fertilizer will make me get the most strawberries on my plants.
Remember: Independent Variable is what I control
Remember: Dependent is what I am looking for
Remember: the control group does not get the independent variable

23. Data Data collected is of 2 types:
Quantitative- numbers, measurements, etc.
temperature, length, mass, etc.
Qualitative – non-number data that cannot be expressed as a number
Shapes, colors, smells, etc.

24. Data practice...
What kind of data would I have collected in my strawberry experiment?
Quantitative
Why?
Because I was counting the number of strawberries

25. Scientific Errors Poor measuring techniques Researcher bias
Poor experimental design
Same person should do all measuring, same machine used throughout, etc.