1. Science is a way of thinking, questioning, & gathering evidence.
So, how do scientists gather evidence & make discoveries?

2. The Scientific Method

3. Scientists study life using the scientific method.
Follow steps of a scientific investigation (inquiry)
a. Observe: make an observation of the world around you
Scientists look critically & attempt to avoid all sources of bias in an observation.

4. 2 Types of Observations
Qualitative: an observation of a characteristic or quality
The plant is dark green.
Quantitative: a numerical observation
The graduated cylinder contains 6.6 mL of water.

5. The sky is blue.
Qualitative
Quantitative
Qualitative!

6. There are 4 clouds.
Qualitative
Quantitative
Quantitative!

7. There are 3 hills.
Qualitative
Quantitative
Quantitative!

8. The 1st hill is small.
Qualitative
Quantitative
Qualitative!

9. The clouds are small.
Qualitative
Quantitative
Qualitative!

10. There are 38 birds.
Qualitative
Quantitative
Quantitative!

11. The Scientific Method
b. Ask a question: based on your observation, ask a question to investigate
You want your question to be answerable!
“Which color is the prettiest?” is not a testable question.

12. The Scientific Method
c. Research: look in books, journals, internet, etc. to make additional observations & research about your question

13. The hypothesis must be testable!
The Scientific Method
d. Formulate a hypothesis: propose an answer or explanation to your question. At the end of the investigation, you will either accept or reject your hypothesis.
The hypothesis must be testable!

14. This is the actual hands-on part of the project.
The Scientific Method
e. Perform a controlled experiment: develop & use the experimental design to test your hypothesis
This is the actual hands-on part of the project.
Here, you carry out your manipulation & compare the results with results from a control setting.

15. Variables in an Experiment (factors being tested)
Independent Variable: variable being manipulated (changed on purpose)
On a graph, found on the x-axis
Dependent Variable: variable that responds
On a graph, found on the y-axis
Control Group: the group where the independent variable is not applied; used for comparisons
Controlled Variables: variables that are held constant
In an experiment, ONLY CHANGE 1 VARIABLE AT A TIME!

16. Does Miracle Grow help plants grow larger?
How would you set up this experiment?
For this experiment, you need 2 plants (a test group & a control group).
1 plant will be planted in regular soil, but the other will be planted in Miracle Grow soil.
Which plant is my control group?
The plant with regular soil is the control group.
The plant with the Miracle Grow is the test group.

17. Does Miracle Grow help plants grow larger?
There should only be 1 difference between the test group & the control group!
In this experiment, the only difference is the type of soil used (regular or Miracle Grow).
ALL OTHER FACTORS MUST REMAIN THE SAME!
Controlled variables: same type of plant, same amount of sunlight, same amount of water, etc.

18. Does Miracle Grow help plants grow larger?
The 1 difference between the test group & the control group is the independent variable.
So what is the independent variable in this experiment?
The independent variable is the type of soil used!
This is what you changed on purpose.

19. Does Miracle Grow help plants grow larger?
The variable that changes in response to the independent variable is the dependent variable.
What is the dependent variable in this experiment?
The dependent variable is the plant growth!
This is what you are measuring.

20. The Dependent Variable The Independent Variable
DEPENDS ON
The Independent Variable
(Plant growth depends on the type of soil.)

21. Does Miracle Grow help plants grow larger?
Independent Variable: type of soil used
Dependent Variable: amount of plant growth
Controlled Variables: amount of sunlight, water, etc.
Control Group: plant with regular soil
Test Group: plant with Miracle Grow
Notice that these are not the same thing!

22. 1. Independent Variable? ___________________
Students at DHS wanted to test if paper weight affects the distance paper airplanes fly. The same type of paper airplanes were folded from three different weight papers. The planes were thrown in the mall area to measure the distance they would fly. What are the following variables?
Weight of paper
1. Independent Variable? ___________________
2. Dependent Variable? ____________________
Distance the plane flew

23. 1. Independent Variable? ___________________
A group of students was asked to compare the taste of lemonade. One glass was from a pitcher made with one cup of sugar. The second glass was made from a pitcher with two cups of sugar. Both pitchers used the same amount of water, lemon juice, and ice. What are the following variables?
Amount of Sugar
1. Independent Variable? ___________________
2. Dependent Variable? ____________________
Taste

24. Squidward loves playing his clarinet and believes it attracts more jellyfish than any other instrument he has played. In order to test his hypothesis, Squidward played a song on 3 instruments for a total of 5 minutes and counted the number of jellyfish he saw in his front yard. He also recorded the number of jellyfish he observed when he was not playing an instrument.
3 trials with no music
1. What is the control group? _____________________________
2. What is the independent variable? _______________________
3. What is the dependent variable? ________________________
Instrument
Number of jellyfish

25. How do scientists study life?
f. Collect Data: perform analysis on the data using graphs & charts

26. How do scientists study life?
g. Draw conclusions: state whether or not the evidence supports the hypothesis based on your data & analysis h. Report back to the community!