1. Experimenting with Science

2. If you VARY something, you CHANGE it
If you VARY something, you CHANGE it. You might VARY or CHANGE your hair!

3. You might VARY or CHANGE what you eat.
On Monday, Wednesday, Thursday, and Friday, I ate pizza
for lunch.
On Tuesday, I varied from my usual diet and ate a hamburger for lunch.

4. Scientists VARY
or CHANGE
things to see
what happens.

5. What does it mean to vary something?
If we VARY it, we CHANGE it!

6. When scientists vary something…
…we call that an experiment.
…or a test.
…or a trial.

7. For a trial to be FAIR,
a scientist can only change ONE thing at a time.

8. Scientist wonder…hmm…
Hmm…I wonder…

9. Scientists start with a question
Hmm…I wonder…
Does fertilizer really
make a plant grow
bigger,
OR does Home Depot just want to take our money?

10. To answer this question,
scientists will only change
ONE thing,
the amount of ____________!

11. The ONE thing that is changed,
is called the
INDEPENDENT
VARIABLE.

12. INDEPENDENT
means
By itself
All alone
Just that one

13. All the plants start out exactly the same.
Same type, same age, same size.

14. All the plants get watered the same amount.

15. Each plant is watered at 8a.m. and 6p.m.

16. But,
ONE thing is VARIED…

17. One thing was changed on purpose!

18. The plants receive different amounts of FERTILIZER

19. Since the fertilizer is the one thing we changed on purpose,
we call
it the
INDEPENDENT
VARIABLE!

20. WE DID NOT CHANGE

21. The amount of water each plant received.
WE DID NOT CHANGE
The type of plant.
The amount of water each plant received.
The time the plants
were watered.
The amount of
sunlight the plants
received.

22. We CONTROLLED the water, sunlight, and the type of plants!
That means we kept them the same.

23. They are the CONTROLLED VARIABLES!
So the
- plants
- water
- time
- sunlight
all stayed the same!
They are the CONTROLLED VARIABLES!

24. SAME! We CONTROLLED them. We did not let them change at all.
We made them stay the very
SAME!
We did not let them change at all.

25. Guess what happened to the plants?????????

26. The plants that had
fertilizer grew
taller
and larger!

27. The growth depended on the fertilizer.

28. So, we call that growth the DEPENDENT Variable.
The growth of the
plant was the
Dependent Variable.
The growth depended on the fertilizer, the change we made on purpose.

29. The DEPENDENT variable…
DEPENDS on the independent variable.
It is measured or counted at the end of an experiment

30. How would a scientist write the hypothesis for this experiment?
A hypothesis is an educated prediction about the experiment.

31. It is written as an If, Then Statement

32. If I add fertilizer to a plant,
What is the other magical word in the hypothesis?

33. Then

34. If I add fertilizer to the plants
Then…

35. If I add fertilizer to the plants,
THEN
the plants will grow bigger.