Physic skills

Question 1

Absolute Uncertainties

Answer 1

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

Question 2

Accuracy

Answer 2

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

Question 3

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

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

Control Variables

Answer 5

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

Question 6

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

Digital apparatus

Answer 7

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

Question 8

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

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

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 on the graph

Question 11

Line of Best Fit

Answer 11

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

Question 12

Percentage uncertainties

Answer 12

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

Question 13

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

Random errors

Answer 14

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 15

Repeatable

Answer 15

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

Question 16

Reproducible

Answer 16

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

Question 17

Resolution

Answer 17

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

Question 18

Resolution of forces

Answer 18

The splitting of a force into its horizontal and vertical components

Question 19

Scalar quantities

Answer 19

A quantity that only has a magnitude without an associated direction

Question 20

SI units

Answer 20

The standard units used in equation - meters, kilograms, seconds, amps, Kelvin and moles

Question 21

Significant figures

Answer 21

A measure of a measurement’s resolution.

Question 22

Systematic erros

Answer 22

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

Question 23

Triangle of forces

Answer 23

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 triangel

Question 24

Vector quantities

Answer 24

A quantity that has both magnitude and an associated direction

Question 25

Vernier scales

Answer 25

Type of scale used on callipers and micrometers, that involve reading from a fixed scale and a moving scale to produce accurate measurements

Question 26

Zero errors

Answer 26

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 27

Pico(p)

Answer 27

x10^-12

Question 28

nano(n)

Answer 28

x10^-9

Question 29

milli(m)

Answer 29

x10^-3

Question 30

centi(c)

Answer 30

x10^-2

Question 31

kilo(k)

Answer 31

x10^3

Question 32

mega(M)

Answer 32

x10^6

Question 33

giga(G)

Answer 33

x10^9

Question 34

tera(T)

Answer 34

x10^12

Question 35

percentage uncertainty (formula)

Answer 35

(absolute uncertainty/actual value) x100

Question 36

Rules for calculating overall uncertainty when quantities have been combined

Answer 36

When quantities have been added or subtracted, add the absolute uncertainties for
each value.
When the quantities have been multiplied or divided by each other, add the
percentage uncertainty for each value
When a quantity is raised to a power n, multiply the percentage uncertainty for this
value by n.

Question 37

uncertainty from a graph

Answer 37

(gradient of best line - gradient of worst line)/gradient of best line x100