Reef and Granny

Have a look at what happens when you pull a reef knot and a granny knot tight. Which do you think is best for securing things together? Why?
Exploring and noticing Working systematically Conjecturing and generalising Visualising and representing Reasoning, convincing and proving
Being curious Being resourceful Being resilient Being collaborative


This is a reef knot:

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Reef and Granny


And this is a granny knot:

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Reef and Granny


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:

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Reef and Granny


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

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Reef and Granny


... or this:

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Reef and Granny


or this:

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Reef and Granny


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

Why?