Principles of experimentation

Question 1

To ensure that experiments are conducted fairly the following concepts should be considered: (4)

Answer 1

1. Careful planning and design
2. Ensure that the experiment is safe
3. Design a control experiment
4. Experiments must be fair

Question 2

How are experiments designed and planned carefully?

Answer 2

In most experiments, only a single factor/variable is tested. All other variables should be kept constant.

Question 3

How do you ensure that the experiment is safe? (7)

Answer 3

Tie back long hair.
Wear a laboratory coat.
wear safety goggles when necessary.
Never place your fingers in your eyes or mouth unless you have washed your hands.
Avoid contact between electrical equipment and water.
Be aware of the safety information when using chemicals.
Report all accidents to a teacher.

Question 4

What is a control experiment?

Answer 4

A control is a comparison for the test experiment.

There should be only one variable between the test experiment and the control.

Question 5

What four factors must be considered for an experiment to be fair? (4)

Answer 5

Sample size
Random selection
Others must be able to reciprocate experiments
Double-blind testing

Question 6

Explain the need for sample size for fairness.

Answer 6

Normally as large a sample as possible is tested.
1. A large sample produces more reliable results.
2. It is representative of the whole population.
3. Allows for illness and death
When carrying out an experiment, it is important that more than one person or object is being tested.

Question 7

Explain the need for random selection for fairness.

Answer 7

When selecting a sample to be tested, the selection should be random. This is to prevent bias by the person carrying out the experiment.

Question 8

Explain the reasons why others must be able to reciprocate experiments is necessary for fairness.

Answer 8

Experimental work is reported so that the information discovered is widely available to all. Once the work is properly reported it can be repeated by others. In this way, the results can be shown to be always true and not caused by some unknown influence.

Question 9

Explain the need for double-blind testing for fairness.

Answer 9

When double-blind testing is used, the tester cannot influence the results of the experiment by consciously or unconsciously giving clues to the person being tested.

Question 10

What should a good experiment contain?

Answer 10

A variable, a control, designed to avoid bias, designed to be reproducible, safe, ethical