Practical skills - paper 1 and 2

Question 1

Define an indépendant variable

Answer 1

The one variable that you change

Question 2

Define a dependant variable

Answer 2

The variable that you measure

Question 3

Define a control variable

Answer 3

Any variable you keep the same to make it a fair test

Question 4

Define directly proportional

Answer 4

If one variable increases the other variable increases at the same rate. eg if x doubles then y must double

Question 5

Define inversely proportional

Answer 5

If one variable increases the other variable decreases at the same rate. eg if x doubles then y must halve

Question 6

Define an anomalous result

Answer 6

An result which does fit the pattern of trend

Question 7

Define interval

Answer 7

The spacing between measurements eg 0, 10, 20, 30 40, 50 cm would have an interval of 10

Question 8

Define range

Answer 8

The maximum and minimum values eg 0, 10, 20, 30, 40, 50 would have a range of 50 - 0 cm

Question 9

Define resolution

Answer 9

The smallest change that can be measured with a particular piece of equipment

Question 10

How can the uncertainty in a measurement be measured?

Answer 10

Half of the range

Question 11

When should you draw a line graph

Answer 11

When both variables are continuous

Question 12

When should you draw a bar graph

Answer 12

If one of the variables is discrete or categoric

Question 13

Define a continuos variable

Answer 13

Can be recored as any number eg time, mass, volume

Question 14

Define a discrete variable

Answer 14

Can be recored only as a whole number eg number of goals in a match

Question 15

Define a catergoic variable

Answer 15

If recorded in words instead of numbers eg colours or types of metal

Question 16

Vernier calipers can measure distance to the nearest 0.01 cm. A meter ruler can measure to the nearest 0.1 cm. Which would be better for measuring the width of an object?

Answer 16

The Vernier calipers have a higher** resolution. The meter ruler has a **lower resolution. The Vernier calipers would be more accurate

Question 17

How can you convert from cm³ into m³?

Answer 17

Divide by 1000000 (100³)

Question 18

How can you convert from mm³ into m³?

Answer 18

Divide by 1000000000 (1000³)

Question 19

Define a random error and give an example

Answer 19

A random error is an error in a measurement that is different each time. This causes points to be scattered around a line of best fit on a graph.

An example would be using a stopwatch and starting or stopping it too early

Question 20

Define a systematic (zero) error and give an example

Answer 20

An error that will be the same on all measurements. For example an electronic balance that reads 0.05 g before anything is place on it. All readings will be too high.

Question 21

If an electronic balance has a zero error (records a reading when it should say 0.00 ) how could this be corrected?

Answer 21

1. Reset the balance to zero
2. Record the zero error and add or subtract it from all your measurements

Question 22

If a stop clock reads 18.72 seconds, what is its resolution?

Answer 22

0.01 s

Question 23

If a voltmeter reads 3.6 V what is its resolution?

Answer 23

0.1 V

Question 24

What are the benefits of peer review?

Answer 24

detects false claims

detects inaccurate data

detects bias

verifies new data

Question 25

How can you check if results are precise?

Answer 25

Take repeat readings. If the results are close together then they are precise

Question 26

What are the benefits of repeat readings?

Answer 26

Spot anomalies

Calculate an average

The average should reduce the effect of random errors.