Experimath - Experiment 11

Syllabus links

Key Stage 2 (age 7 to 11)

Can you find the mass of an object by using water?

This experiment gives children an opportunity to practise measuring volume and mass and use their creativity in making an improvised weighing scale.

The child will learn how to construct and use a scale for measuring mass.

2 plastic cups

string or wool

a pair of scissors

a coathanger

a measuring jug

some clear aquarium hose (optional)

some toy cars

some marbles

sticky tape

felt tip pens

Create your improvised weighing scale as shown.
Make sure that the clear hose is tightly tied into the hanger.
Fill the hose with enough water as indicated by the tiny red lines.

Make sure that the water can move freely without getting blocked by a fold in the middle of the tube.
Mark the water levels with a felt tip pen.

These marks will tell you whether or not your cups contain objects of equal masses.

Using your improvised weighing scale, a measuring cup and some water, measure the masses of your marbles and toy cars.

Record the results.

Every after weighing an object, check that water levels go back to their original state.

1 litre of water has a mass of exactly 1 kilogram.

This will depend on exactly what is being weighed.
This will also depend on exactly what is being weighed.

The important thing is that the child conducts the experiment as accurately as the scale allows.
You can check the answer by putting the smallest toy car on one side of the scale and the largest marble on the other side.

Check the accuracy of your improvised weighing scale by comparing your results with that when a kitchen weighing scale is used.
Use counters of known mass like pence instead of water.

You should find that the improvised scale is quite accurate.
The advantage of using pennies is that you can count them more easily than you can measure a quantity of water.

Experiment 11 v5