Give Me Ideas For A Lesson on Number Bases/ Binary/ Hexadecimal

i know i've seen or read some sci-fi stuff about aliens with crazy numbers of fingers that use different number bases.

http://www.youtube.com/watch?v=3l2NP6K_iuk

little twelvetoes is the jam

wow!

http://www.youtube.com/watch?v=nDM8ULV_HEA

How old are these mad smart kids? Are they too old to be impressed by (or too young to cope with the addition for, but I doubt that given your lesson plan) this old card trick? http://meeyauw.blogspot.com/2007/12/merry-binary-christmas.html
Can you borrow a binary watch to pass round?

Maybe this is dumb or obvious, but I had a o_O moment in my teens when I realized that adding up track times for mixtapes involved base-six for one column of numbers and base-10 for all the others.

i taught a lesson on binary to my madsmart year 8s about a month back, they loved it. Do consider that nobody how crazy smart they are, thinking in base 2 is really difficult at first if you;ve never considered it before. give them a chance to play around with it and convert between binary and decimal before you show them arithmetic.

Here is some stuff i did:

I started the lesson by telling them that by the end of the lesson they would be able to count to 1023 on their fingers.

Got them to write down only the whole numbers that zeros and ones in them which shows them how to count up in binary.

Reminded them that decimal place value was increasing powers of ten, leading from the right. Replaced this with increasing powers of two (used 10 places so i could compare it with fingers later in the lesson) and asked them to identify binary numbers,and convert decimal numbers into binary.

Showed them this worksheet http://download.yousendit.com/287964AC738F983E

Then asked them to imagine their fingers as the 10 place values from the board, and to count up from 1 to 10 with me and beyond. I used this to help

http://www.lyzrdstomp.com/binary/bin1-7.html

and this

http://www.lyzrdstomp.com/binary/bin1-7.html

I stupidly didn't realise at the time that several number will lead to them swearing at each other but played it for laughs so it's all good.

Then i gave them a few minutes to challenge each other in pairs and threes to represent numbers on fingers or to identify numbers form fingers.

I showed them the binary clock

http://www.glassgiant.com/geek/binaryclock/binary_clock_flash.swf

and then we did some adding and subtracting with binary numbers (which they enjoyed more than i thought because it's surprisingly easy and powerful)

Then we sort of ran out of time.

Hope some of this is helpful.

Do consider that nobody how crazy smart they are

should read "do consider that however crazysmart they are"

Sorry i got excited and started typing drivel

counting in base 4 using the digits of one hand might work for this.

if you have access to a large library, take a look at the first chapter of "New Mathematical Diversions from Scientific American" by Martin Gardner. I have lost my copy, but I seem to remember it being a particularly good article.

just read it back and realised that "Got them to write down only the whole numbers that zeros and ones in them which shows them how to count up in binary." might be a bit unclear.

what i meant if they are writing down the whole numbers but ignoring every number containing a 2,3,4,5,6,7,8 or 9 then they can see for themselves why it goes 0, 1, 10, 11, 100 etc in a very natural way.

One more thing that i wish i'd considered before i taught it is that there is bound to be at least one kid who just doesn't get it full stop, so have something ready for them.

This wooden binary marble adding machine is awesome but seeing as it moves too fast for the binary-unfamiliar to follow and you're not really going to build your own in the next few days I paste it mainly to, uh, clutter up your thread, I guess.
http://www.youtube.com/watch?v=GcDshWmhF4A

My mother suggested this knitting needle binary sort thing but I think again it's too much faff and not clear enough (I've seen it before and didn't really follow it, so it'd take too much time to explain):
http://wildaboutmath.com/2008/01/02/impressive-math-magic-with-16-index-cards/

I reckon you've probably got at least enough stuff, but yeah, an opening gimmick is nice.

My teacher friend just reminded me of a relevant puzzle:

"how can i arrange 15 pennies into 4 envelopes so that i am able to pay any amount of money from 1p to 15p without taking the pennies back out"

the answer is binary!

I'll shut up now.

This thread was better than I hoped. Thanx slumpman and others!

How did it go?

Oh, I got hired! Thanks all.