physics skills

• Explain why new data from Rutherford's alpha particle scattering experiment led to a change in the model of the atom
• Explain, with an example, why new data from experiments or observations led to changes in models or theories
• Give examples of ways in which a model can be tested by observation or experiment
• Suggest why scientific data might be uncertain, incomplete or not available
• Explain why data is needed to answer scientific questions, and why it may be uncertain, incomplete or not available
• Describe and explain how the motor effect is applied in an electric motor
• Describe and explain specified examples of the technological applications of science
• Give examples to show that there are hazards associated with science-based technologies which have to be considered alongside the benefits
• Suggest reasons why the perception of risk is often very different from the measured risk
• What is peer review and what is its purpose?
• Explain why reports of scientific developments in the popular media are not always reliable
• Plum pudding model


  Predicted that no alpha particles would deflect significantly
• A small number of alpha particles did deflect significantly
• New atomic model


  Positive charge in a massive nucleus at the centre
• Motor effect


  1. Wire is wound into a coil

  2. Two sides of the coil experience forces in opposite directions

  3. A split ring commutator reverses the current every half term, to reverse the forces and keep the coil spinning
• Reasons why scientific data might be uncertain, incomplete or not available

  • The experiment is too expensive to carry out
  • The experiment is too dangerous to carry out
  • The experiment is unethical
  • We do not have the technology for the experiment
  • Countries or organisations may not share their data
• Reasons why the perception of risk is often very different from the measured risk

  • Whether the risk is voluntary or imposed
  • Whether the risk is familiar or unfamiliar
  • Whether the hazard is visible or invisible
• Examples of hazards associated with science-based technologies


  • The risk of cancer when having an X-ray
  • The risk of climate change when burning fossil fuels
  • The risk of meltdown when using a nuclear reactor
  • The risk of new cancer caused by radiotherapy
• Peer review


  • Scientific work is reviewed by other scientists before being published
  • It helps to detect false claims and to establish a consensus about which claims should be regarded as valid
• Reports of scientific developments in the popular media are not always reliable
• • They are not subject to peer review
  • They may be oversimplified, inaccurate or biased
• Independent variable


  The variable that is changed or selected by the investigator
• Dependent variable


  The variable that is measured for each change in the independent variable
• Accurately using a measuring cylinder


  1. Use a suitable sized cylinder (so that it is fairly full, so the uncertainty is small compared to the actual measurement)

  2. Ensure clean and empty before use

  3. Place on a level surface

  4. Eye level with scale to avoid parallax error

  5. Measure from the bottom of the meniscus
• Control variable


  Variables that are kept the same because they would affect the dependent variable if they changed
• The length of this line is 6.3 cm or 63 mm
• The vernier calliper reading is 5.12
• The voltmeter reading is 4.4 V
• The micrometer reading is 9.86 mm
• The number of different measurements needed in an experiment depends upon the experiment. AQA seem to like at least seven different measurements, with repeat readings
• Finding the gradient of a particular point on a curved graph

  1. Draw a tangent at the point (a straight line that touches the curve at that point)

  2. Draw a large right angled triangle on the tangent

  3. Use the graph scale to determine the size of the vertical side of the triangle, y

  4. Use the graph scale to determine the size of the horizontal side of the triangle, x

  5. Calculate the gradient = y ÷ x
• Finding the area under a curved graph

  1. Use the graph scales to calculate the value of one square (multiply the two sides)

  2. Count the total number of squares between the line and the x-axis

  3. To find the area under the graph, multiply the value of one square by the number of squares counted
• What earns marks when plotting a graph

  • Axes titles with quantity and unit
  • Linear scales (numbers equally spaced out)
  • Scales that use more than half the graph paper in each direction
  • All points plotted to within half a small square
  • Line or curve of best fit with a balance of points on either side of the line
• Significant figures


  Use the same significant figures that the question used. If different significant figures were used for different numbers, use the lowest significant figures, as this will limit the significant figures of your answer
• Range of a set of data

  The largest value minus the smallest value
• Frequency table


  A table listing how often each value appears in a set of data
• Order of magnitude


  Finding the nearest power of ten. So rather than finding an exact answer, just find whether it is closest to 1, 10, 100, etc. If it is closest to 100, you would say is has an order of magnitude of 102 or just 2
• Rearranging the equation a = b/c to make c the subject


  1. Multiply both sides by c... a × c = b

  2. Divide both sides by a... c = b/a
• Determining the slope (gradient) of a linear graph

  1. Draw a large right angled triangle on the graph, with the line of best fit forming the hypotenuse

  2. Use the graph scale to determine the size of the vertical side of the triangle, y

  3. Use the graph scale to determine the size of the horizontal side of the triangle, x

  4. Calculate the gradient = y ÷ x
• Determining the intercept of a linear graph


  1. Check that the graph has a true origin (0,0)

  2. Read off the value on the y-axis where the line crosses the y-axis

  3. (If the graph has a false origin then you could find the gradient and read off any pair of values of x and y, and then substitute into y = m x + c to find c)