Problem Solving & Exam Technique

Question 1

How do you calculate a percentage change?

Answer 1

difference/original x 100%

Question 2

If the question asks, ‘what is the difference between’…?

Answer 2

you must mention BOTH things

Question 3

If the question asks, ‘calculate the average’…what do you do?

Answer 3

the total/the number of numbers you added together

Question 4

If the question asks, ‘calculate the average change’…what do you do?

Answer 4

total change/ time

Question 5

BUM?

Answer 5

Box the command word
Underline the key terms
Marks - how many is it worth? Have I done enough?

Question 6

If the question asks you to ‘describe’…what should you do?

Answer 6

As much detail as you can give.

The police have asked for a description of the person that stole your bike, you would not describe them as ‘man’.

Question 7

If the question asks you to ‘explain’…what should you do?

Answer 7

Tell me WHY

Question 8

How do you read a graph accurately?

Answer 8

Use a ruler

Question 9

What is an independent variable?

Answer 9

The one thing that has been changed by the scientist in the experiment

Question 10

What is a dependent variable?

Answer 10

The thing that is measured to get the results in an experiment.

Question 11

What words should never be used in a answer

Answer 11

“It”and “amount”

Question 12

2 reasons why an experiment may be left for a period of time before measurements are taken?

Answer 12

1. allow living organisms to acclimatise to new conditions
2. allow apparatus to stabalise
3. allow osmosis/diffusion to happen
4. allow solutions to reach desired temperatures

Question 13

Why are percentage changes sometimes calculated in results tables?

Answer 13

If the starting figures were different it allows a comparison to be made.

Question 14

If a questions asks you to ‘Using data from the graph, describe’…what should you do? (not a trick question!)

Answer 14

Guess what, USE DATA FROM THE GRAPH!!! NUMBERS in your description

Question 15

Is a question asks you to ‘draw a conclusion’, what should you do?

Answer 15

1. Look at the aim and answer that
2. Mention the independent and dependent variables in your answer (the dependent variable might not be what is stated in the table/graph - look at the aim!!!)

Question 16

What should you do if the question asks you to ‘state variables that must be kept constant’?

Answer 16

Read the experiment carefully and decide which variables NOT mentioned already that would need to be kept the same to make it fair.

Question 17

3 possible examples of variables that must be kept the same?

Answer 17

temperature
volumes
concentrations
mass
surface area
diameter of samples
thickness of samples
time
pH

Question 18

Which variable always goes on the bottom of a graph?

Answer 18

The independent variable

Question 19

What should you do if the question asks you ‘how many times greater’ is X than Y?

Answer 19

Divide the big number by the small number

Question 20

How do you calculate a simple whole number ratio?

Answer 20

Divide all of the numbers in the ratio by the same number until they cannot be divided any more.

Question 21

How do you calculate what each small square is worth on the scale of a graph?

Answer 21

the increase in number between the big lines/number of small squares