1.Practical Skills

Question 1

What are Absolute Uncertainties?

Answer 1

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

Question 2

What is Accuracy?

Answer 2

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

Question 3

What is Analogue Apparatus?

Answer 3

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

Question 4

What are Anomalies?

Answer 4

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 5

What are Control Variables?

Answer 5

Variables that must remain the same throughout an experiment so as to not affect the results.

Question 6

What are Dependent Variables?

Answer 6

The variable being measured in an experiment. It is dependent on the independent variable. The dependent variable should be plotted on the y-axis of a graph.

Question 7

What is Digital Apparatus?

Answer 7

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

Question 8

What is a Fiducial Marker?

Answer 8

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 measurements.

Question 9

What is Gradient?

Answer 9

The change in the y-axis value over the change in the x-axis value between two points. If the graph is curved, a tangent can be drawn to calculate the gradient at a specific point.

Question 10

What are Independent Variables?

Answer 10

The variable that is changed by the experimenter in an experiment. The independent variable should be plotted on the x-axis of a graph.

Question 11

What is a Line of Best Fit?

Answer 11

A line drawn on a graph to demonstrate the pattern in the plotted data points.

Question 12

What are Percentage Uncertainties?

Answer 12

The uncertainty of a measurement, expressed as a percentage of the recorded value.

Question 13

What is precision?

Answer 13

A measure of how close a measurement is to the mean value. It only gives an indication of the magnitude of random errors, not how close data is to the true value.

Question 14

What are prefixes in measurement?

Answer 14

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

Question 15

What are random errors?

Answer 15

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

Question 16

What does repeatable mean in experiments?

Answer 16

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

Question 17

What does reproducible mean in experiments?

Answer 17

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

Question 18

What is resolution in measurement?

Answer 18

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

Question 19

What is resolution of forces?

Answer 19

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

Question 20

What are scalar quantities?

Answer 20

A quantity that only has a magnitude, without an associated direction.

Examples include speed, distance and temperature.

Question 21

What are SI units?

Answer 21

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

Question 22

What are significant figures?

Answer 22

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

Question 23

What are systematic errors?

Answer 23

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

Question 24

What is the triangle of forces?

Answer 24

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 25

What are vector quantities?

Answer 25

A quantity that has both a magnitude and an associated direction.

Examples include velocity, displacement and acceleration.

Question 26

What are vernier scales?

Answer 26

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 27

What are zero errors?

Answer 27

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.