Tag Archives: circles

199. Video of the week: Constructing Pentagons

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I came across this video whilst looking for 3D construction ideas for a 7 year olds homework. It is a very easy to follow video explaining how to construct a pentagon using a ruler, pencil anda  pair of compasses. When I say easy, I mean it. The voiceover is in Spanish and all my knowledge of Spanish comes from watching ‘Dora the Explorer’ with the children – and I still understood how to do this.

Not only will it help pupils improve their fine motor skills using compasses, you could also ask more able students why it works. You could also ask Spanish speakers to translate!

 

 

178. Santa’s Secret

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Santa’s secret is that he can get your class to revise harder topics – without them realising!

Equipment

Activity
Paper chains are made from equally sized strips of paper. Each loop is made from a strip of paper, which has one end glued to the other.

Question 1
How many 3cm by 18cm strips of paper can you cut from a sheet of A4 paper? Remember, each strip is made from one complete piece of paper.

Question 2
If each strip has an overlap of 1cm, what is the circumference of the loop made? What is the diameter?

Question 3
When two loops are attached there is an overlap of 0.5cm. How long would a chain of 12 loops be?
Hint: two loops with diameter 4cm would have a combined length of (4+4-0.5)cm = 7.5cm.

Question 4
A room has dimensions 5m by 7m. How far is it diagonally across the room?

Question 5
How many loops would a paper chain have if it reached diagonally across the room?

Extension
To make the chain hang in U shape, rather than stretching flat across the ceiling, 5 extra loops are added per whole metre of chain. How long would the chain diagonally across the room be? How many loops?

Challenge
How many sheets of paper would be required to make enough paper chain to hang in a U shape joining every corner of the room?

82. Gadget of the Day 1

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What are these?

compasses1

I came across them when I was making a circle skirt and it occurred to me they’d be a great teacher tool. They’re generally known as a yardstick compass. You attach the pointy end to one end of a metre (or yard) stick and the pencil end at your desired radius. Each end has a cap which tightens to the height of your ruler. Hey presto – a giant pair of compasses! Never again will you search high and low for something big and circular to draw around or try using a drawing pin and a piece of string.

compasses2

There are lots of American websites that sell them, but in the UK I’ve only seen them on Art supply sites eg Handover.co.uk