Module 1

Question 1

What is the difference between independent and dependent variables?

Answer 1

• Independent variables are what you change in an investigation. Dependent variables are what is observed or measured
• Independent variables are normally the cause of the effect on the dependent variables

Question 2

What are control variables?

Answer 2

Control variables are any other quantities that could change the value of the dependent variable and need to be kept constant during the experiment

Question 3

How should you scale your axes?

Answer 3

Regular intervals and the plotted data should take up at least 50% of the graph

Question 4

How should a line of best fit be drawn?

Answer 4

It should be a straight line that goes through the middle of the data - there should be an equal number of plotted points either side of the line

Question 5

When drawing a line of best fit on a graph with error bars what must you do?

Answer 5

Ensure the line of best fit goes through all the error bars

Question 6

How do you find the uncertainty in the gradient of a line of best fit?

Answer 6

• Draw a steepest or shallowest line of worst fit which goes through all the error bars
• Then, calculate the gradients of the best and worst line
• The uncertainty will be the difference between the best and worst gradients.

Question 7

How can you find the percentage uncertainty in the gradient of a line of best fit?

Answer 7

= (best gradient - worst gradient) / best gradient * 100

Question 8

How do you work out the uncertainty in the y-intercept of a line of best fit?

Answer 8

= Best y-intercept - worst y-intercept

Question 9

How do you find the percentage uncertainty in a y-intercept?

Answer 9

= (best y-intercept - worst intercept) / best y-intercept * 100

Question 10

What is an estimation?

Answer 10

A skill physicist must use in order to approximate the values of physical quantities; this is done in order to make comparisons, or to check if a calculated value is reasonable.

Question 11

What is absolute uncertainties?

Answer 11

The interval that a value is said to lie within, with a given level of confidence

Question 12

What is accuracy?

Answer 12

A measure of how close a measurement is to the true value

Question 13

What is Analogue apparatus?

Answer 13

Measuring apparatus such as rulers, beakers and thermometers that rely on the experimenter reading off a scale to determine the measurement

Question 14

What is Anomalies?

Answer 14

Data points that don’t fit the pattern of the data. You should determine why an anomalous result has occurred before removing it. Repeat readings help remove anomalies.

Question 15

What is Digital apparatus?

Answer 15

Measuring apparatus such as ammeters, voltmeters and digital calipers that digitally measure and display a measurement

Question 16

What is Fiducial marker?

Answer 16

A thin marker, such as a splint, that is used to ensure readings are taken from the same place each time. They are used to improve the accuracy of measurement.

Question 17

What is Gradient?

Answer 17

= Change in y / change in x

Question 18

What is Precision?

Answer 18

A measure of how close a measurement is to the mean value. It only gives and indication of the magnitude of random errors

Question 19

What is Prefixes?

Answer 19

Added to the front of units to represent a power of ten change.

Question 20

What is Random errors?

Answer 20

Unpredictable variation between measurements that leads to a spread of values about the true values. Random errors can be reduced by taking repeat measurements

Question 21

What is Repeatable?

Answer 21

The same experimenter can repeat a measurement using the same method and equipment and obtain the same value.

Question 22

What is Reproducible?

Answer 22

An experiment can be repeated by a different experimenter using a different method and different apparatus, and still obtain the same result.

Question 23

What is Resolution?

Answer 23

The smallest change in a quantity that causes that causes a visible change in the reading that a measuring instrument records.

Question 24

What is Resolution of Forces?

Answer 24

The splitting of a force into its horizontal and vertical components.

Question 25

What is Scalar quantities?

Answer 25

A quantity that only has a magnitude.

Question 26

What is SI units?

Answer 26

The standard units used in equations. They are: meters, kilograms, seconds, amps, Kelvin, moles and candela.

Question 27

What is Significant Figures?

Answer 27

A measure of a measurement’s resolution. All numbers except zero are counted as significant figure. When zeros are found immediately after a decimal place, they too are counted.

Question 28

What is Systematic errors?

Answer 28

Causes all readings to differ from the true values by a fixed amount. Systematic error cannot be corrected by repeat readings, instead a different technique or apparatus should be used.

Question 29

What is Triangle of forces?

Answer 29

A method of finding the resultant force of two forces. The two forces are joined tip to tail and the result is then the vector that completes the triangle.

Question 30

What is Vector quantities?

Answer 30

A quantity that has both a magnitude and a direction.

Question 31

What is Vernier scales?

Answer 31

The type of scale used on calipers and micrometers, that involve reading from a fixed scale and a moving scale to produce accurate measurements.

Question 32

What is Zero errors?

Answer 32

A form of systematic error caused when a measuring instrument doesn’t read zero at a value of zero. This results in all measurements being offset by a fixed amount

Question 33

What is the rate of change of momentum

Answer 33

Force * time