# Hints and Tips: Getting it Right in Practical Papers

READ ALL the question first. You have plenty of time. Imagine the apparatus in front of you.

Measurement on-site. For lengths, make sure you have a good quality ruler, able to measure accurately to 1mm. You are usually provided with pretty much everything you might need and, if you are, it’s important to use it all. As an example, if you’re measuring the diameter of a marble and they give you six, plus a ruler and two set squares, this is the way to do it.

Decide where a measurement is to be taken (top/middle/bottom) For example, the length of a pendulum is measured from the support to the middle of the lead weight.

First create a table with headers, then write the measurements down to the nearest unit on the measuring instrument (such as 1 degree or 1mm)

The question often asks you to process the measurement in some way (work out an area or volume/divide by a number of oscillations/ find the sine of an angle/find a volume.) Do the algebra or rearrange first. Then put in the numbers. Quote your answer to the number of decimal places in the question and don’t forget units.

There is often data where you have to fill in the units and there will always be a graph to plot (e.g, a cooling curve) Use sensible and easy-to-plot scales for the graphs and remember that the axes have units. Draw the LOBF through as many data points as possible. Look down the points to see whether it’s a straight line or not. If it is, use a ruler. If not, draw freehand a smooth curve and, if you’re using error bars the line MUST go through them all, both vertical and horizotal Use a sharp HB pencil

The graph tells you something. Think about what the data is telling you β they will either ask you to work out a gradient or an area. Gradients β big is beautiful and keep it simple β look out for division by easy numbers. Both gradient and area under will have units.

You are sometimes asked to read meters. Be careful about accuracy and sensitivity. We used to use these big demonstration meters in school but now mostly they are all digital. You should know how to read both, however.

Precautions to ensure accuracy. When reading meters, volumes from measuring cylinders, lengths and so on, avoid parallax errors. Repeat measurements and average as time allows (3 is good) and zero all meters are the usual ones to write down when asked to comment.

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