2. EXPERIMENTS!
Mr. Pearl before drinking his coffee

4. An experimental design included references
from prior experiments, materials and equipment ,and step-by-step procedures. What else should be included before the experiment can be started?
(1) a set of data
(2) a conclusion based on data
(3) safety precautions to be used
(4) an inference based on results

6. The steps again are… Problem- What you study and why.
Background – What is already known.
Hypothesis- What you THINK is true.
Controlled Experiment- Design, implement,
and collect data from AT LEAST 2 groups.
Analyze Data- Study results for patterns
and errors.
Conclusion- Is hypothesis correct?

8. Controlled Experiment
Design, implement, and collect data from AT LEAST 2 groups to COMPARE results.
CONTROL GROUP EXPERIMENTAL GROUP
Group that has ONLY ONE change.
For example, plants grown at a higher temperature than usual, or patients that take a newly invented medicine.
Group that is treated “normally”.
For example, plants grown at the same temperature as always, or patients that take a placebo (fake pill) instead of real medicine.

10. CONTROL only water EXPERIMENTAL
Water & Nitrogen
Two groups are set up to test the effect of nitrogen on the growth of garlic bulbs. Which group is the control and which is the experimental?

12. There are two types of variables!!!!
Independent
You “control” this. It is what you are testing. It comes from your hypothesis. You know it BEFORE the experiment even starts.
Dependent
You measure this during the experiment. It is what you want to know. It is what you compare. You DO NOT KNOW THIS until the experiment occurs.

14. An experimental setup is shown in the diagram below.
Which hypothesis would most likely be tested using this setup?
(1) Green water plants release a gas in the presence of light.
(2) Roots of water plants absorb minerals in the absence of light.
(3) Green plants need light for cell division.
(4) Plants grow best in the absence of light.

15. What is the independent variable here?
The light!

16. What is the dependent variable here?
The bubbles!

18. A television ad claims that a certain brand of cough drop reduces coughing for 8 hours. Design a controlled experiment to determine if this claim is valid.
You MUST include:
The treatment to be given to the experimental group and to the control group.
Two variables that must be kept constant in both groups.
The data to be collected.
When the data should be collected.
One observation that would support the hypothesis.

19. A television ad claims that a certain brand of cough drop reduces coughing for 8 hours. Design a controlled experiment to determine if this claim is valid.
You MUST include:
The treatment to be given to the experimental group and to the control group.
The control group subjects will not take a cough drop, and the experimental group subjects will take a cough drop.

20. Two variables that must be kept constant in both groups.
A television ad claims that a certain brand of cough drop reduces coughing for 8 hours. Design a controlled experiment to determine if this claim is valid.
You MUST include:
Two variables that must be kept constant in both groups.
People in both groups must have a cough, and must be around the same age.

21. The data to be collected.
A television ad claims that a certain brand of cough drop reduces coughing for 8 hours. Design a controlled experiment to determine if this claim is valid.
You MUST include:
The data to be collected.
The number of people coughing.

22. When the data should be collected.
A television ad claims that a certain brand of cough drop reduces coughing for 8 hours. Design a controlled experiment to determine if this claim is valid.
You MUST include:
When the data should be collected.
During the experiment, for a period of 8 hours.

23. One observation that would support the hypothesis.
A television ad claims that a certain brand of cough drop reduces coughing for 8 hours. Design a controlled experiment to determine if this claim is valid.
You MUST include:
One observation that would support the hypothesis.
If less people taking the cough drop cough.