Measurement of Length and Motion: common misconceptions

If your child says… “Everyone’s own handspan will give the same count for this table.”

Ask together

If our measuring units differ, why should our counts match?

What’s true

Different handspan sizes can give different counts along the same table.

If your child says… “One big unit equals one small unit.”

Ask together

How many millimetre spaces can you count inside one centimetre?

What’s true

One centimetre contains ten millimetres, as the ten small spaces on the ruler show.

If your child says… “The number at the far end is the length.”

Ask together

Which part of the ruler before the eraser have you also counted?

What’s true

The far-end reading includes the unused distance before the object’s starting point.

If your child says… “The straight gap measures the curve.”

Ask together

Does a straight line across the bowl follow its edge?

What’s true

The straight gap between the ends is shorter than the curved path.

If your child says… “The reference point is always where measuring ends.”

Ask together

When we say ‘from the door’, where does measuring begin?

What’s true

The reference point is the fixed place used to describe another position.

If your child says… “Something moving must be moving compared with everything.”

Ask together

Does the coin change place on the tray?

What’s true

An object can move compared with one reference point and rest compared with another.

If your child says… “A swing moves in a circle because its path curves.”

Ask together

Does the book complete a circle when it moves to and fro?

What’s true

A swing reverses direction instead of continuing around a circle.

If your child says… “Only circular motion can be periodic.”

Ask together

Does the spoon need to go around a circle to repeat after equal times?

What’s true

Equal repeat times determine whether motion is periodic.