Science and measurement

It has been said that science is measurement. This may be going a little too far, but it is certainly true that measurement is very important in science. Without measurement there could be no science. Measurement could be called the heart of science. If we can’t measure something, we can't apply the full power of scientific method to study it.

Qualitative descriptions and quantitative descriptions

Read these two descriptions

A. This body is greenish, with a rough surface. It has the shape of a leaf with pale markings on it.

B. This body is about 15 cm long and 10 cm wide. It is about 2 mm thick, and roughly leaf shaped. The surface is dark green and rough to the touch. There is a deep groove in the centre of the long axis, with smaller grooves running from this centre line to the edges

Description A is qualitative. It tells about qualities (characteristics), such as colour, shape and roughness.

Description B also gives some qualitative information, but it gives measurements as well. This is the sort of description that a scientist might give. It is quantitative it gives information about quantities-and it is more detailed.

Quantitative information is very important in science. Scientific method involves using measuring instruments of many different sorts.

All measurements involve at least two pieces of information: a number or magnitude and a unit. We should always use both together. The unit tells us what is being measured, the number tells us how much of it.

Here are some examples of measurements: 5 grams; 2 hour; 25 litres; 3.6 metres; 100 kilometres. Notice that each example gives both a number or magnitude and a type of unit.