Practical Skills/Foundation

Question 1

vernier scale

Answer 1

type of scale used on micrometers reading from a fixed scale and a moving scale

Question 2

reproducible

Answer 2

different experimenter, same method, different equipment

Question 3

repeatable

Answer 3

same experimenter, same methods, same equipment

Question 4

fiducial marker

Answer 4

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 5

independent variable

Answer 5

the variable that is changed

Question 6

dependent variable

Answer 6

the variable that is measured

Question 7

control variable

Answer 7

the condition that is kept constant

Question 8

Why do repeat readings?

Answer 8

Can spot anomalous results more easily and reduce the effect of random error

Question 9

What does precise mean?

Answer 9

How close the readings are to each other with a particular instrument. The more precise, the more decimal places the value is.

Question 10

What does reliable mean?

Answer 10

How small the range of data spread is. The more reliable, the closer together they all are.

Question 11

What does valid result mean?

Answer 11

all control variables are controlled and experiment answers question with precise data.

Question 12

What does accurate mean?

Answer 12

result is close to true answer.

Question 13

What is the uncertainty for a measuring instrument?

Answer 13

half of the smallest measurement it can measure

Question 14

What do we need to note about measuring lengths?

Answer 14

equipment uncertainty doubled because there is uncertainty at each end of the ruler.

Question 15

What is absolute uncertainty?

Answer 15

the total uncertainty of a measurement

Question 16

What is percentage uncertainty?

Answer 16

the uncertainty given as a percentage of the measurement.

Question 17

What is the assumed uncertainty?

Answer 17

half the increment of the last significant figure. e.g. 2.0 is 0.05.

Question 18

Name the 6 SI base units

Answer 18

kilogram, metre, second, ampere, kelvin, mole

Question 19

what is a systematic error

Answer 19

shifts all the values by the same amount

Question 20

what causes systematic error?

Answer 20

parallax, calibration, lining up of a ruler, not zeroing the scale

Question 21

what is a random error?

Answer 21

parallax, human error

Question 22

How to combine uncertainties?

Answer 22

add/subtract - add ab
multiply/divide - add %
powers - multiply % by power

Question 23

What is percentage difference?

Answer 23

Difference between experimental and actual value given as a percentage of actual value

Question 24

what is a scalar?

Answer 24

the magnitude of something - no direction

Question 25

what is a vector?

Answer 25

something with magnitude and direction

Question 26

How to draw worst line?

Answer 26

from top of top error bar to bottom of bottom error bar.

Question 27

Are energy and power vectors or scalars?

Answer 27

vectors

Question 28

Why are values for average speed and velocity different?

Answer 28

one vector, one scalar, displacement always in a straight line which is less than or equal to distance