Measurement  (IGCSE)

Experimental techniques (2.1 Measurement- Core)

Name appropriate apparatus for the measurement of time, temperature, mass and volume, including burettes, pipettes and measuring cylinders.

1. Mass

The S.I. unit for mass is the kilogram (kg). Other commonly used units are milligrams (mg), gram (g) and tonne (t). The electronic balance is used for precise and fast weighing of small amounts of substances with an accuracy of up to ±0.01 g.

2. Time

The S.I. unit for time is the second (s). Other commonly used units are minute (min) and hour (h). Time is usually measured with digital stopwatch which has an accuracy of 0.01s.

3. Volume

The S.I. unit for volume is the cubic metre (m3). Other commonly used units are cubic centimetre (cm3) and cubic decimetre (dm3).

 Apparatus Properties Beaker Used to estimate volume of liquid. Used when precision is not needed. Can measure up to 50 cm3 of liquid. Measuring cylinder More accurate than a beaker. Measures up to the nearest cm3. Burette Accurately measures variable volumes of liquid to the nearest 0.05 cm3. Can be used to deliver different volumes of liquids from 0.00 to 50.00cm3. Pipette Accurately measures fixed volumes of liquid. e.g. 10.0 cm3, 25.0 cm3

How to read volume of a liquid?

When a liquid is poured in a glass container, there would be a curved surface at its top. This curved surface is called a meniscus. Align your eyes to the liquid level. The gas syringe is commonly used to measure to volume of a gas. It measures a maximum volume of 100 cm3.

4. Temperature

The S.I. unit for temperature is the kelvin (K). The degree Celsius (oC) is also commonly used. Temperature in K = Temperature in oC + 273. Temperature is usually measured using mercury thermometer or alcohol thermometer which has an accuracy of ±0.5oC.
When you read the temperature on a thermometer, thermometer should be vertical and not slanted, your eyes should be level with the meniscus in the glass tube.