1. Biology as a Science

2. I designed an experiment to see if the amount of water affected the height of the grass.
I gave plot A 1
gallon of water per
week.
I gave plot B 2
gallons of water per
After 4 weeks, the
grass in plot B was
taller than in plot A
Can I say for sure that water affects the height of grass? A B

3. Video Video Is this a good experiment?
Is there something they could improve upon?
Can you tell for sure if elephants are afraid of mice?

4. Parts of a Controlled Experiment
1. Testable Question
Def: This is a question that can be answered by an experiment
Usually only one factor at a time is investigated
Good examples:
***Does the amount of fertilizer affect the number of flowers on a plant?
Is a person’s heart rate affected by 5 hour energy?
Bad example:
Why is the sky blue?
What happens after you die?

5. Parts of a Controlled Experiment
2. Hypothesis
Def: A hypothesis is an explanation or prediction that can be tested

6. Good examples: Bad example:
Does the amount of fertilizer affect the number of flowers on a plant? ***I think adding fertilizer will cause a plant to produce more flowers
Is a person’s heart rate affected by 5 hour energy? I think 5 hour energy does not affect a person’s heart rate
Bad example:
Why is the sky blue? I think blue is pretty
What happens after you die? I think I’ll be reincarnated as a unicorn

7. Parts of a Controlled Experiment
3. Independent Variable
Def: This is what you are changing on purpose to see if it has an effect on whatever you’re testing
Does the amount of fertilizer affect the number of flowers on a plant?
***The independent variable would be the amount of fertilizer
4. Dependent Variable
Def: This is what you are measuring or observing as a result
Does the amount of fertilizer affect the number of flowers on a plant?
***The dependent variable would be the number of flowers that grow on the plant
5. Controls
Def: The things that are the same for all experimental groups
Ex: ***water, sunlight, temp.

9. Parts of a Controlled Experiment
6. Procedure
Def: Step by step instructions
Why is it important to write a good procedure?
Your experiment needs to be able to be repeated so that someone else can see if they get the same results that you did
7. Data
Information you collect (with units) in a table and/or graph

10. Good bar graphs
Title
Depend. Variable
Independent Variable
Start at 0

11. Parts of a Controlled Experiment
8. Conclusion
Includes: What does your data tell you?
Example: Because all of the plants produced the same number of flowers, that must mean that fertilizer does not affect the number of flowers on a plant.

12. What did we learn yesterday?
Diapers hold more plain water than urine
Temperature and color don’t make a difference in how much liquid a diaper can hold
Saltiness does make a difference in how much liquid a diaper can hold
Diapers hold less when there is salt in the water

13. Today’s Experiment Group 1 & 2 Group 3&4 Group 5&6
0% salt 5% salt 10% salt
We want to see if the amount of salt affects the amount of liquid a diaper can hold
What is the only thing that should be different group to group?
What are we measuring?
What needs to be the same group to group?
At least 2 people at every lab table

14. What makes something absorbent?
Absorb means to take in or soak up
The more something can absorb, the more absorbent it is
Cellulose sponges are more absorbent than natural ones
How absorbent something is depends on a wide variety of factors

15. Why are diapers so absorbent?
The crotch of the diapers is filled with a special polymer
A polymer is a long chain of molecules
A molecule is one or more elements put together
A molecule of water is 2 hydrogens and 1 oxygen

16. Why are diapers so absorbent?
The crotch of the diaper is filled with a special polymer called sodium polyacrylate
When it is dry, it’s all curled up in coils

17. Why are diapers so absorbent?
When it touches water, it uncoils and leaves certain molecules exposed

18. Why are diapers so absorbent?
These molecules are like magnets
They attract (absorb) water

19. Why can’t they absorb as much salt water as distilled water?
The salt takes up some of the “spaces” on the polymer so the water has nowhere to “park”

20. What does this teach us about babies and diapers?
Diapers will be more absorbent when the baby’s urine is less concentrated

21. All living things …..

22. Have DNA that is copied and passed from parent to offspring

23. Are made of one or more cells

24. Grow and develop by adding more cells and/or making the cells look different from each other

25. Respond to a stimulus in their environment

26. Evolve over long periods of time (as a group)

27. Take in materials and energy and builds up or breaks down the materials through metabolism

28. Obtain homeostasis by keeping their internal environment stable

29. Reproduce to make offspring, either sexually or asexually

30. Living or non-living?

31. Characteristics of Living Things
Can you name at least 5 of them?
Can you tell me whether something is living or non living and use the characteristics to explain why/why not?
How many do you have to have to be considered living?