1. 10-4-17 Experimental Design

2. Do Now: Answer the following in your science notebook
Review your vocabulary words thus far and write down their definitions.
Control group
a standard of comparison for checking or verifying the results of an experiment where all variables must be held constant
Experimental group
the group(s) being tested with the independent variable.
Repeated trials
a way to validate data by performing an investigation multiple times.

3. Questions to ask yourself to identify the essential parts of an experiment
To identify Independent Variable: What is believed to be causing something to happen?
To identify the Control Group: Which of the levels is considered the most “normal”? What are you trying to compare to?
To identify the Experimental Group: Which of the levels is the experimenter interested in testing?
To identify Dependent Variable: What is believed to be effected?
To identify Constants: What are some things that could affect the dependent variable that you would not want?

4. Corners Practice:
You want to measure the effect of different amounts of oxygen on the rate of yeast growth. What is the dependent variable?
Different amounts of oxygen
Rate of yeast growth
Answer: Rate of yeast growth

5. Corners Practice:
An entomologist (bug scientist) wants to determine if temperature changes how many times a cricket chirps. What is the independent variable? 
Temperature
How many times a cricket chirps
Bug scientist
Answer: Temperature

6. Corners Practice:
You want to test a new drug that supposedly prevents sneezing in people allergic to grass. What is the independent variable? 
New drug
Sneezing
People allergic to grass
Answer: New drug

7. Corners Practice:
You think that a certain part of your brain is important in memory. To test this, you will remove this part of the brain from rats and see if they remember how to get through the maze. What is the dependent variable in this experiment? 
Part of the brain
Rats getting through a maze
Memory
Answer: Memory

8. Corners Practice:
You want to see if playing music makes plants grow taller. What is the dependent variable in this experiment? 
Music
Plant growth
Answer: Plant growth

9. Corners Practice:
A soap manufacturer wants to prove that their detergent works better to remove tough stains. What is the dependent variable? 
Detergent
Soap manufacturer
Removing stains
Answer: Removing stains

10. Corners Practice:
Orchids were studied to determine if the amount of humidity affected the flowering of these plants. Which of these was the independent variable in this study? 
Humidity
Orchids
Flowering of orchids
Answer: Humidity

11. Corners Practice:
A florist wants to see if Product X will extend the life of cut flowers so that they last longer. What is the independent variable? 
Product X
Flower life
Florist
Answer: Product X

12. Student Work: Jigsaw Practice of Experimental Design
Groups of 3 will be assigned to focus on 1 of 4 scenarios.
Each student will be responsible for determining one of the following for each scenario:
Independent variable
Dependent variable
Constants & repeated trials
Each student performs their role individually.
After 5 minutes, each student is going to get together with the other students in each group who have the same role (e.g., all the Independent variable students will get together). These are Expert Groups.
In each Expert Group, you will share your ideas one by one.
Then, students will return to their original group to share their answers.

13. Scenario 1
Ultraviolet light
Skin cancer
Same age
Stella thinks that if people are exposed to ultraviolet light then they are more likely to get skin cancer. Stella designs an experiment wherein group A consisted of people were exposed to ultraviolet light and group B was not. Stella then waited 10 years and followed up with experiment subjects about whether they got skin cancer.
Follow up with experiment subjects after 10 years and ask whether they had skin cancer
No UV light
Live in similar areas
Similar health habits
Ultraviolet light exposure 1
IV: What is believed to be causing something to happen?
Control: Which of the levels is considered the most “normal”?
Experimental Group: Which of the levels is the experimenter interested in testing?
DV: What is believed to be effected?
Constants: What are some things that could affect the dependent variable that you would not want?

14. Scenario 2
temperature
Leaf color
Same plants
Justin believes that the temperature lowering during the fall months is what causes the color of the leaves to change. He set up an experiment wherein he placed some plants in 80 degrees Fahrenheit rooms and some in 60 degree rooms. He then observed the color of the leaves for a total of 1 month. At the end of the month Justin observed that ¾ of the plants in the 60 degree temperature had been to change colors and only ¼ of the plants in the 80 degree temperature began to change colors. Justin completes his experiment every month for 1 year.
Whether plants are beginning to change colors
80 degrees F
Same amount of sunlight
Same soil
60 degrees F
Same amount of water 12
IV: What is believed to be causing something to happen?
Control: Which of the levels is considered the most “normal”?
Experimental Group: Which of the levels is the experimenter interested in testing?
DV: What is believed to be effected?
Constants: What are some things that could affect the dependent variable that you would not want?

15. Scenario 3
Color of light
Plant growth
Same species
Suzie wants to know how different colors of light effect the growth of plants. She believes that plants can survive the best in white light. She buys 5 ferns of the same species, which are all approximately the same age and height. She places one in white light, one in blue light, one in green light, one in red light and one in the closet. All of the ferns are planted in Miracle-Grow and given 20 mL of water once a day for 2 weeks. After the two weeks, Suzie observes the plants and measurements. Suzie repeats her experiment 3 times.
Height
White light
Same age
Same starting height
Blue light
Same fertilizer
Same amount of water
Green light
Same time to grow
Red light 3
IV: What is believed to be causing something to happen?
Control: Which of the levels is considered the most “normal”?
Experimental Group: Which of the levels is the experimenter interested in testing?
DV: What is believed to be effected?
Constants: What are some things that could affect the dependent variable that you would not want?

16. Scenario 4
Flower Power fertilizer
Flower production
Same size plants
SpongeBob loves to garden and wants to grow lots of pink flowers for his pal Sandy. He bought a special Flower Power fertilizer to see if will help plants produce more flowers. He plants two plants of the same size in separate containers with the same amount of potting soil. He places both plants on a sunny window and waters one every day with fertilized water and the other with plain water. He repeats his experiment 50 times.
Count the number of flowers
Plain water
Same amount of potting soil
Same location
Fertilized water
Same amount of water 50
IV: What is believed to be causing something to happen?
Control: Which of the levels is considered the most “normal”?
Experimental Group: Which of the levels is the experimenter interested in testing?
DV: What is believed to be effected?
Constants: What are some things that could affect the dependent variable that you would not want?