1. Scientific Method Review
Run this PPT show to help you review for your midterm.

2. The problem of an experiment is in the form of a ____.
Question

3. A ______ is an educated guess to the problem of the experiment.
Hypothesis

4. The ___________ states whether your hypothesis is correct or incorrect.
conclusion

5. What would make the results of an experiment carried out by a research team valid?
The experiment was repeated and the same results were obtained each time.

6. The _______ group does not contain the independent variable.
control

7. What is measured is known as the ______ variable.
dependent

8. A new idea that is tested in a scientific experiment is known as the ________.
hypothesis

9. To test the effect of hormones on plant growth, 6 potted plant seedlings of the same species were measured and then sprayed with a growth hormone. After 4 weeks of growth under ideal conditions, the plants were measured again.
How would you set up the control group?
There should be another group with 6 plants that DO NOT receive water.

10. 2. Identify the independent and dependent variables.
To test the effect of hormones on plant growth, 6 potted plant seedlings of the same species were measured and then sprayed with a growth hormone. After 4 weeks of growth under ideal conditions, the plants were measured again.
2. Identify the independent and dependent variables.
Independent variable: Growth hormone
Dependent variable: Length of the seedling

11. To test the effect of hormones on plant growth, 6 potted plant seedlings of the same species were measured and then sprayed with a growth hormone. After 4 weeks of growth under ideal conditions, the plants were measured again.
3. Give 2 factors that must be kept constant.
The amount of water each plant receives.
The temperature the plants were kept.
The species of plant used.
The amount of soil in each pot.

12. You studied the effect of the amount of fish food on the mass of goldfish. One tank of goldfish is fed the normal amount of food once a day. A second tank of goldfish was fed twice a day. A third tank of goldfish was fed three times a day. The fish's mass was measured three times a week.
State the problem.
Give a possible hypothesis.
What is the effect of the amount of fish food on the mass of goldfish?
I think that feeding the goldfish three times a day will increase the mass of the goldfish the most.

13. You studied the effect of the amount of fish food on the mass of goldfish. One tank of goldfish is fed the normal amount of food once a day. A second tank of goldfish was fed twice a day. A third tank of goldfish was fed three times a day. The fish's mass was measured three times a week.
3. Identify the independent variable.
4. Identify the control group.
The amount of food
The group of goldfish that were fed once a day.

14. The mass of the goldfish.
You studied the effect of the amount of fish food on the mass of goldfish. One tank of goldfish is fed the normal amount of food once a day. A second tank of goldfish was fed twice a day. A third tank of goldfish was fed three times a day. The fish's mass was measured three times a week.
3. Identify the dependent variable.
4. Identify 2 controls (factors that must remain constant).
The mass of the goldfish.
Amount of fish in each group
Temperature of the water
Amount of light the fish are exposed to
The original mass of the fish

15. Identify the independent variable.
Water temperature
Average water flea heart rate
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16. Identify the independent variable. 2. Identify the dependent variable.
You want to test which size soccer is easier to juggle with your feet. You test the size 3, size 4, and size 5 ball. You count the number of seconds the ball stays in the air for each trial. You allow yourself to use both feet, knees and head to juggle the ball.
Identify the independent variable.
2. Identify the dependent variable.
The size of the soccer balls.
The number of seconds the ball stays in the air.

17. 3. What can be done to increase the validity of the experiment.
You want to test which size soccer is easier to juggle with your feet. You test the size 3, size 4, and size 5 ball. You count the number of seconds the ball stays in the air for each trial. You allow yourself to use both feet, knees and head to juggle the ball.
3. What can be done to increase the validity of the experiment.
Repeat the experiment.
Use a larger sample size.

18. State the relationship between the average water flea heart rate and water temperature.
As water temperature increases, the average water flea heart rate increases.
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19. What is the average flea heart rate at 15ºC?
118 beats/min
What is the average flea heart rate at 30ºC?
240 beats/min
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20. The results of one experiment carried out by a research team would be considered valid if
1. the experiment had no control setup 2. all the members of the research team came to the same conclusion 3. the experiment had more than one variable 4. the experiment was repeated and the same results were obtained each time

21. Why do scientists make graphs of data from experiments? 
to observe general trends and patterns in the data
to make the observed data more accurate
to prevent errors in measuring data
to help change the original data tables

22. Which is the dependent variable in Amelia's experiment?
the number of bean plants in each group
the amount of water given daily to each plant
the height of each bean plant
the amount of fertilizer given to each group of bean plants

23. A new idea that is tested in a scientific experiment is known as a(an)
theory
hypothesis
inference
observation

24. Which statement about the use of independent variables in controlled experiments is correct?
A different independent variable must be used each time an experiment is repeated.
The independent variables must involve time.
Only one independent variable is used for each experiment.
The independent variables state the problem being tested.

25. An investigation is carried out to determine the effect of exercise on the rate at which a person can squeeze a clothespin.
In this investigation, the independent variable is the
control
exercise
rate of squeezing
number of participants

26. An investigation is carried out to determine the effect of exercise on the rate at which a person can squeeze a clothespin.
In this investigation, the dependent variable is the
control
exercise
rate of squeezing
number of participants

27. Why do scientists consider any hypothesis valuable?
A hypothesis requires no further investigation.
A hypothesis may lead to further investigation even if it is disproved by the experiment.
A hypothesis requires no further investigation if it is proved by the experiment.
A hypothesis can be used to explain a conclusion even if it is disproved by the experiment.