Explaining infinity?

[thatsenough]

DS year 1 has developed an obsession with infinity, so far my explanations have been met with a blank face - I've tried a never ending road, space doesn't end etc.

Have any of you got a good explanation I can try?

Wow, I can't believe the fantastic response I've had to this and the great suggestion for explaining to DS.

I think my problem is that I tend to over complicate things rather than keeping them simple.

I will now try and make sense of the later posts

look it up in the dictionary dim wit ;)

No need to use a dictionary I know what infinity is - Explaining at something below degree level was my problem, which is why I could never be a teacher!

The children's picture books 'can you count to a Googol' and 'Is a blue whale the biggest thing there is?' are good on very large (but not infinate) numbers and sizes (the blue whale one is really excellent for thinking about the mind boggling size of the universe).

'The Number Devil' has a section on infinately large and infinately small numbers, amongst other mind boggling mathematical stuff - it's a chapter book/story with maths, you have to read it from the beginning - highly recommended!

For you there is 'The Infinate Book' in adult popular science, which is a good read.

Infinite, even..

Thanks Himalaya, DS loves reading fact books with me - Enjoying "Horrible Geography" at the moment.

galois - I love you

Thanks galois.

Apart from the real numbers / counting numbers being different infinities, are there any other child-friendly ones that are different from both of these? (I know DS will be sad that some of the things he thought were different are actually the same... so wondered if I could tell him about any 'replacements' for his earlier ideas)

teacherwith2kids re other infinities - you start getting into quite hard maths there, more masters level than undergraduate. There's this thing called the continuum hypothesis which is something you have to assume, as we can't "prove" it with the axioms we have.

A nice child friendly infinity is the sort you get with fractals, as these are good to look at. A fractal is a geometric shape which repeats itself infinitely. If it gets smaller as it repeats then you can have an infinite object in a finite amount of space. So it can be infinite and you can hold it in your hand. (In real life, because things stop at the atomic level it can't actually be infinite, but in theory it could be).

You can draw fractals, and look at lots of very cool pictures on the computer made of them.

I used to do a maths club with the most keen Y6 children at a local school, and the child friendly but not on the NC bits of maths we did included:

pictures of MC Escher and impossible objects
bridges of konigsberg problem (and working out rules for similar problems)
adding 1+2+3+4+... and finding cool shortcuts
fruit algebra (paper algebra with a+c+2x=3y tends to be a bit too abstract at this age, but 2 apples + 3 bananas = 4 apples + £2 worked a treat when they were actually holding the fruit, and they were able to solve simultaneous equations with three variables at the end of it).
basic ramsey theory
basic set theory
games with prime numbers

The one thing I did that left the kids thoroughly confused was try to do imaginary numbers. That one didn't work with 10 year olds :)

Galois, don't pretend to understand any of what you say but you make it sound exciting and fun anyway. Wish I had had teachers like you

Galois, oddly, my son is quite happy with the idea of imaginary numbers - he has an orderly mind and didn't like the fact that -1 has no square root, so knowing that there is one and it's called i fills a 'gap' for him.