Scientific Communication (Edexcel A Level Physics): Revision Note

Scientific Communication

• Scientific communication of the results of an experiment are extremely important

• The ideas must be communicated in an appropriate way using appropriate terminology

  • This involves using terms such as accuracy, validity and stating the sources of random and systematic errors

• Scientists have to design an experiment to answer a question or investigate something

• These will involve dependent and independent variables

  • An independent variable is what is changed

  • A dependent variable is what is measured

  • The control variables are what do not change

• For example, in an investigation of the variation of potential difference and current across a light bulb

  • The independent variable is the potential difference

  • The dependent variable is the current

  • The control variable would be the temperature of the apparatus

• Data must always be presented in a scientific way

• This may include:

  • Tables

  • Graphs

  • Diagrams

Presenting Data in Tables

• When taking readings, a sensible range should be taken, and the values should all be stated to an appropriate number of significant figures or decimal places

  • This is usually the same number as the resolution of the measuring instrument

• The columns in any table should have both a quantity and a unit in their heading

  • When labelling columns, the names of the quantities should be separated from their unit by a forward slash ( / )

• For data displayed in a table:

  • The first column should contain the independent variable

  • The second column should contain the dependent variable

  • If repeat readings of the dependent variable are required, these should be included with a column for the mean value at the end

  • Any columns required for processing data e.g. calculations should come after this

  

  Conventions for presenting data in a table. The length is the independent variable and the frequency is the dependent variable

• In summary, when presenting tables the following must be included:

  • Clear headings, or symbols, for columns

  • Relevant units for measurements

  • Readings listed to the same number of significant figures

An example of a correctly labelled table with corresponding graph

Presenting Data on a Graph

• All readings, including suspected anomalous results, should be plotted on a graph so that they can be easily identified

• When taking repeat readings, it is the mean value that is plotted

• The way data is presented on a graph depends on what type of data it is

Discrete data

• Only certain values can be taken, normally a whole number e.g. number of students

  • This should be displayed on a scatter graph or bar chart

Continuous data

• Can take any value on a scale e.g. voltage in a circuit

  • This should be displayed on a line or scatter graph

Categorical data

• Values that can be sorted into categories e.g. types of material

  • This should be displayed on a pie or bar chart

Ordered data

• Data that can be put in ordered categories e.g. low, medium, high

  • This should be displayed on a bar chart

• In summary, when presenting graphs the following must be included:

  • An explanatory title

  • Clearly labeled axes

  • Relevant units for measurements

  • Well plotted points

  • A smooth line or curve of best fit

An example of a correctly labelled and plotted graph

Presenting Diagrams

• When presenting diagrams, such as apparatus set-up, all the relevant parts must be clearly labelled

An appropriately labeled diagram of the set-up of an investigation into simple harmonic motion