Measuring accurately
Make systematic and careful observations, and take accurate measurements in standard units using suitable equipment such as rulers, thermometers, measuring jugs and scales
What a learner can do afterwards
- Use at least three types of measuring equipment correctly (ruler, thermometer, measuring jug, scales)
- Read measurements in standard units (cm, ml, °C, g) with reasonable accuracy
- Make systematic observations by following a planned method consistently
1 · Read
You have practised looking closely. Measuring adds a number and a unit to an observation. A ruler measures length or height. Centimetres are written cm. Choose a ruler long enough for the object.
Line up one end of a pencil with the ruler's zero mark. Look straight down at the mark beside the other end. The hop shows a pencil spanning 0 to 7 cm, so its length is 7 cm.
A thermometer measures temperature: how hot or cold something is. In this lesson, we use degrees Celsius, written °C. The cm marks on a ruler measure length. The ml marks on a jug measure liquid volume.
A systematic method follows planned steps. Use the same measuring method each time and record each result with its unit. If you change the method, write down what changed.
A measuring jug measures liquid volume in millilitres, written ml. Put the jug on a level surface. With an adult's help, pour in the water. Read the bottom of its curved surface at eye level. Scales measure mass, not volume.
Sam records 14°C at 9am, 19°C at 12pm and 17°C at 3pm. Each bar label gives its time and temperature. Find the time you need, then read the temperature in that label. Bar heights help you compare the temperatures.
For a liquid-in-tube thermometer, wait until the liquid line settles before reading it. Look at the number beside the top of the line. Write the number and °C. An adult should help you use the thermometer safely.
Mass and volume are different measurements. Grams, written g, measure mass. Millilitres, written ml, measure volume. Water can have both a mass and a volume. To measure mass, put scales on a level surface and check zero. With a container, reset to zero before adding water.
Choose the right tool, read it closely in the correct units, and measure the same way every time.
Four original readings about rainfall records, ruler measurements, scales and measuring jugs, written for this dataset.
2 · Watch
Take it off screen
Where it sits
Where this leads
8 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.