Designing Investigations

Question 1

The variable you change is…

Answer 1

…The independent variable

Question 2

The variable you measure is the…

Answer 2

…Dependent variable

Question 3

The variables you keep the same are the…

Answer 3

…Control variables

Question 4

Give 3 examples of control variables

Answer 4

1. Temperature
2. Concentration of reactants
3. Volume of reactants

Question 5

Why might you do a trial run?

(4)

Answer 5

1+2. They help you figure out the range and interval of variable values

3. Can help you work out the appropriate number of repeats to do

(if 3 trials give similar results, then three repeats are enough)

4. Can help you spot problems with your method

Question 6

If, in a trial run, you don’t get a change in the dependent variable at the lower values, what might you need to do?

Answer 6

Narrow the range in the proper experiment

Question 7

If, in a trial run, you get a big change in the dependent variable at the upper values, what might you need to do?

Answer 7

You might need to increase the range

Question 8

Why can’t the intervals between the values in an experiment be too big?

Answer 8

You might miss something

(pattern/ trend)

Question 9

Why can’t the intervals between values in an experiment be too small?

Answer 9

The experiment will take a long time

Question 10

Give 2 examples of problems a trial run could point out?

Answer 10

1. Whether there’s a way of doing something easier
2. Discovering something to make your results more accurate

Question 11

Define ‘control group’

Answer 11

A group of whatever you are studying kept under the same conditions as the group in the experiment, but doesn’t have anything done with it

(helps you do a fair test)