Planning, Implementing and Analysing Results

Variable

Anything that has the potential to change in an experiment

Independent variable

The thing you change

Dependent variable

The thing you measure

How to ensure your control variables have not messed up your experiment

Measure your control variables too and work out whether they are changing

What to consider when choosing apparatus

-Units of measurements

-Range of measurements

-What the apparatus measures

-Risks of apparatus

What should you do when recording data in a table

-Discard anomalous results

-Average the repeated measurements

Qualitative data

Data that can be given a numerical value

Quantitative data

Data that cannot be given a numerical value

Questions when evaluating an experimental design

-Does the experiment actually test what it is meant to

-Is the method clear enough for someone else to follow

-Is everything controlled

-Are the apparatus and techniques appropriate

-Are enough repeated measurements taken

-Is the experiment going to be conducted safely

-Ethical/environmental considerations

When should you discard anomalous results

If there is a good reason

How should significant figures be handled when analysing data

Give any values to the same number of significant figures as the data value with the lowest significant figures

What is the problem with giving a result to too many significant figures

You are saying that the final result is more precise than it is

Which axis should the independent variable go on

x-axis

Which axis should the dependent variable go on

y-axis

How should points be plotted on the graph

With a sharp pencil

Why should points be plotted onto a graph with a sharp pencil

They are as accurate as possible

How should a line/curve of best fit be drawn

Around half of the data points are above the line and around half of the data points are below the line, excluding anomalous results

Positive correlation

As one variable increases, the other increases

Negative correlation

As one variable increases, the other decreases

No correlation

No relationship between the variables

Linear

The line of best fit is straight

Linear graph equation

y = mx + c

What does it mean if y is proportional to x

The graph is linear and passes through the origin

How to find the gradient of a curved graph

Draw a tangent