Revision Cards Flashcards

1
Q

What does accuracy mean? What can you do to increase the accuracy of an experiment?

A

Results are close to the true value – accuracy can be increased by controlling variables

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2
Q

What is calibration?

A

Marking a scale on a measuring instrument

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3
Q

What is the independent variable?

A

The independent variable is the variable that is changed

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4
Q

What is the dependent variable?

A

The dependent variable is the variable that is measured

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5
Q

Why do we normally use at least 5 different repeats in an experiment?

A

We do 5 tests to obtain a pattern – this will also highlight anomalous results

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6
Q

What is a hypothesis?

A

A proposal to explain certain facts or observations

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7
Q

What is validity? How can you increase the validity of an experiment?

A

A valid experiment tests what it is supposed to – validity is increased by ensuring all variables are controlled, and removing errors (e.g. experimental bias)

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8
Q

What is an interval?

A

The quantity between readings e.g. 10cm, 20cm, 30cm, 40cm, 50cm have and interval of 10cm

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9
Q

What is random error? How can you reduce the impact of random errors?

A

1 or 2 odd results that may be caused by equipment or experimental error – reduce the impact of random error by repeating results and removing anomalies from the average

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10
Q

What is a systematic error?

What should you do if you suspect systematic error?

A

Data which differs from the true value by a consistent amount each time – it is usually caused by the way measuring instruments have been read

Repeat using a different technique or instrument

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11
Q

Explain the following types of data: -

a) Categoric
b) Continuous

A

Categoric: values which are groups or lables (e.g. boys and girls)
Continuous: values which have numbers e.g. time, weight, number of people, distance etc…

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12
Q

What is zero error?

A

When a measuring instrument gives a false reading when it should be zero

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13
Q

What is a precise result?

A

A result which is very similar to the mean value

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14
Q

What is the range?

A

The maximum and the minimum values e.g. from 10cm to 50cm

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15
Q

What is repeatability?

A

When the experimenter repeats the experiment using the same method and gets the same result

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16
Q

What is reproducibility?

A

When the experiment is repeated by another person or by a different method and you get the same results

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17
Q

What is resolution?

A

The smallest change in the quantity being measured e.g. mm on a normal ruler

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18
Q

How do you draw a sketch graph?

A

Label the axes on a sketch like below and draw what you think the line of best fit is like

19
Q

What is uncertainty?

A

The interval within which the true value can be expected to fall, with a given level of confidence or probability, e.g. “the temperature is 20°C ± 2°C, at a level of confidence of 95%

20
Q

What is a control variable?

A

A variable which could affect the results if it isn’t monitored or kept the same

21
Q

What does interpreting mean?

A

To read and summarise the information shown on a graph, table or chart

22
Q

What is a prediction?

A

A statement suggesting what will happen in the future, based on observations / experience / a hypothesis

23
Q

What are environmental considerations?

A

The impact on wildlife and the natural habitat e.g. pollutions

24
Q

What is an opinion?

A

Personal judgments or views which can be formed form scientific evidence or non-scientific ideas

25
Q

What is bias?

A

The influence placed on scientific evidence because of wanting to prove your own ideas, supporting the person paying you, political influences, or the status of the experimenter

26
Q

What does ethical mean?

A

Whether it is right or wrong. E.g. drug testing on animals

27
Q

What are social considerations?

A

What people think e.g. different religions

28
Q

What are economic considerations?

A

Costs involved

29
Q

What is a control group?

A

A group often used in biological and medical research to ensure that observed effects are due to changes in the independent variable alone e.g. a group of people who take a placebo are compared

30
Q

How do you calculate an average?

A

The sum of all the measurements divided by the number of measurements taken

31
Q

When would you use a bar chart?

A

Bar charts can be used to display data in which one of the variables is
categoric

32
Q

When would you use a line graph?

A

Line graphs can be used to display data in which both the independent and dependent variables are continuous

33
Q

When would you use a scatter graph?

A

Scatter graphs can be used to show an association between two variables

34
Q

What is a casual link?

A

When one variable causes a change in another

35
Q

What is a link due to association?

A

Changes in one variable and a second variable are linked by a third variable e.g. different greenhouse gases and global warming

36
Q

What is data?

A

Information that has been collected (numbers / written observations)

37
Q

What are anomalies?

A

Values in a set of results which differ from the expected and variation caused by random uncertainty

38
Q

What is measurement error?

A

The difference between a measured value and the true value

39
Q

What is a valid conclusion?

A

A conclusion supported by valid data, obtained by an appropriate experimental design

40
Q

What is evidence?

A

Data which has been shown to be valid

41
Q

What is a fair test?

A

A fair test is one in which only the independent variable has been allowed to affect the dependent variable

42
Q

What is a true value?

A

The value that would be obtained in an ideal measurement

43
Q

What does reliable mean?

A

A reliable measurement is one that consistently remains the same after several repeats