You may also like

Tangrams

Can you make five differently sized squares from the interactive tangram pieces?

Polydron

This activity investigates how you might make squares and pentominoes from Polydron.

Construct-o-straws

Make a cube out of straws and have a go at this practical challenge.

Reef and Granny

Age 7 to 11 Challenge Level:

This is a reef knot:

reef knot



And this is a granny knot:

granny knot


Before you read any further, it might be a good idea to make a reef knot and a granny knot. You do not need coloured string - it can even be done with shoelaces!

Can you see any differences between them?

When a reef knot is pulled tight it looks like this:

reef knot pulled tight


When a granny knot is pulled tight it looks like this:

granny pulled tight 1


... or this:

granny pulled tight 2


or this:

granny pulled tight 3


Which do you think is the best knot for making things secure?

Why?