Practical tips overview - Shawon Notes

Physics > Practical


Practical tips overview

The examination papers will test your ability to do some of these things:

  • describe the method for an investigation
  • take measurements
  • record results in the table
  • plot graphs to show results
  • analyse results
  • evaluate data

Method

Apparatus: Students might be asked to carry on an investigation using a given set of apparatus or might look for how you use do the measurements with the apparatuses.

While describing an investigation, make sure every step is in correct order.

Reliability: You have to mention ways, how your experiment is more reliable. Some examples include:

  • repeat readings
  • means all the values
  • plotting graphs
  • discard anomalous results

Safety precautions

You might have to mention safety precautions for the experimenter. Some examples include:

  • if you are using weights, make sure they cannot fall and land on your feet
  • make sure any clamp stands are fastened to the bench so they cannot overbalance
  • if you are stretching wires or other objects that might break and spring back, wear eye protection
  • if you are using electricity, make sure you are using a low-voltage source
  • if you are using water, make sure that any spills are mopped up so you do not slip
  • if you are projecting (firing) an object such as a ball bearing or an arrow make sure that no one is in the area and that an adequate absorbent target is in place
  • if you are describing the use of radioactive materials make sure you know how they should be handled and stored safely
  • if you are timing the descent of an object such as a model parachute make sure that any chairs or other furnitures are out of the way

Safety precautions can also refer to care of the apparatus. For example:

  • not stretching a spring too far so that it goes beyond its elastic limit
  • if you are using electricity to heat something, such as fuse wire, use a heatproof mat to protect bench and don’t touch hot wires

Measurements

During measurement, make sure to:

  • add units
  • record results in a table
  • avoid parallax error
  • avoid zero error

Graphs

  • Graphs are a good way of presenting results
  • It helps find anomalous results
  • Know the terms “line of best fit” and “curve of best fit” and when to use them.
  • Know about the types of graphs: line and bar chart and when and where to use them.
  • Be able to describe shapes of graph: linearity, passing through origin, positive/negative slope/correlation, inverse relationship

Analyse results

  • give answers in appropriate significant figures in calculations. The results of calculations should be given to the same number of significant figures as in the measurement to calculate them
  • be able to write conclusion for a set of results or compare a conclusion with prediction. You must say whether the prediction was correct with reason.

Evaluation

  • commenting on sets of results
    • deciding how accurate and reliable
    • how precise or reliable the evidence is
    • how to increase accuracy and reliability
  • Precision
  • Human reaction effects accuracy of measurement.  Use more reliable apparatus for measurement
  • Reliability