Practical Design 3 – Experimental Procedure

Just as a well-written recipe will enable anyone following to create a great dish, a well-written practical procedure should allow anyone following it (even if they have very little physics knowledge) to perform your physics experiment and obtain results.

 

 

The experimental procedure should be a detailed, logical sequence of steps that need to be carried out in order to perform the practical.

Points should be numbered clearly.

  • Usually step 1 will be:

1.  Set up the apparatus as shown in the diagram

  • All measurements must name the measuring instrument used:
      1. Measure the length of string, L, with a metre ruler
      2. Record the time taken for the pendulum to make 20  complete oscillations, t,  with a stop watch.

 

 

Section of the Plan Sample
  • Set-up the equipment
  1. Set up the apparatus as shown in the diagram above.
  • Measure the independent variable or select the object with required variable (e.g. mass, height, angle, resistance).
  1. Measure the length of the pendulum, L, to obtain 100.0 cm with a metre rule.
  • Describe the step(s) of experiment to measure the dependent variable (directly or indirectly).
  1. Displace the pendulum bob and allow it to oscillate vertically through a small angle.
  2. Measure the time taken for 20 oscillations with a stopwatch. Record the time, t1.
  • Repeat step(s) so as to obtain more reliable readings (where relevant) and calculate the average value.
  • Include important/relevant formulae and/or equations used to calculate the dependent variable.
  1. Repeat steps 3 and 4 to measure the time taken for another 20 oscillations. Record the time, t2.
  2. Calculate the average time, tave from the two readings.
  3. Calculate the period of the pendulum, T from the equation T = tave / 20 and the value of T2.
  • Repeat the steps for further measurements (at least another 9 sets of readings) over a suitable wide range (if known).
  1. Repeat steps 2 to 7 for another 9 values of L between 10.0 cm and 90.0 cm.
  • Tabulate all measured (raw data) and calculated (processed data) values.
  1. Tabulate all the readings of L, t1 , t2 , tave , T and T2.
  • Plot a graph of dependent variable (usually on the y-axis) against independent variable (usually on the x-axis).
  • Based on earlier analysis of given equation
  1. Plot a graph of T2 against L straight line graph is expected to be obtained & g can be deduced from the gradient.

Examples of some practicals you may see in Sec 3 & Sec 4:

Pendulum:RollingMarble:Reflection:

 

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