Observing and measuring · Grade 3
Scientists find out about the world by observing carefully with their senses and by measuring. Measuring turns what we see into numbers we can compare, using the right instrument and the right unit.
Key facts
- We observe with our senses: sight, hearing, smell and touch. Never taste anything in science unless a teacher says it is safe.
- Length: a ruler or tape measure (mm, cm, m). Mass: a weighing scale (g, kg). Time: a stopwatch (s, min). Temperature: a thermometer (°C). Volume of a liquid: a measuring jug or cylinder (ml, l). Force: a forcemeter (N).
- Choose an instrument that suits the size of what you measure: a ruler for a pencil, a tape measure or trundle wheel for a playground.
- Before reading a scale, work out what each small mark is worth. Read it with your eye level with the mark.
- 1 cm = 10 mm, 1 m = 100 cm, 1 kg = 1000 g, 1 l = 1000 ml and 1 minute = 60 s.
- Write down what you find straight away, in a table, with the units in the headings.