Tag Archives: logarithms

302. Log Proof Puzzle

If you can guess where today’s blog image came from you obviously consume too much damn fine cherry pie and fresh coffee!

log lady

Image credit: Pinterest

You may have guessed that the topic of this post is logs. If you are introducing the rules for adding and subtracting logs or revising them, I have just the resource for you. It’s a basic proof of both rules with a twist. The instructions are in the wrong order and you must rearrange them into the right order.

Easy!

Are you sure?

For those of you who have a student or two who rush everything and don’t read the instructions there is a sting in the tail. One of the lines of proof is a tiny bit wrong. The methodical student will find it, the one who races through may end up changing more than one line – hence breaking the rules.

Have fun!

Proving log rules for addition and subtraction

Answer: It’s the ‘Log Lady’ from the cult classic ‘Twin Peaks’!

271. Bored with exponentials

I have a Pi-loving colleague who is a whizz with voting presentations.

love pi

Mr D created these review activities for use with A2/C3 students. The focus is logarithms, exponentials and Ln functions, including models for growth and decay. I particularly like the equation measuring boredness in a Maths lesson. It’s obviously wrong – how could a Maths lesson possibly be boring?

Exponentials and logs review (pptx)

Exponentials and logs review (ppt)

Optional Variation

We paired up this presentation with Qwizdom voting handsets. If you don’t have them, you could try out Socrative and turn students’ mobile phones into voting handsets

270. A whiff of cheese and exponentials

Here is an introduction to modelling exponential growth and decay … using cheese!

Exponential growth and decay (pptx)

Exponential growth and decay intro (ppt)

I used this as a starting point whilst teaching the Edexcel C3 course. You could even demonstrate with fresh and not so fresh cheese. I’m sure the staffroom or sixth form fridge will have some ‘interesting’ examples.

251. Safe as trees

Here’s a two in one post for you, with a wooden theme:

safecracker

Tree 1

This fascinating wooden puzzle is available on Etsy. Each line has to add up to 50 – simple? Not as easy as you’d think. A perfect classroom extension puzzle or gift for a puzzle fanatic!

Tree 2

A little starter on logarithms, with a touch of safecracking too!

Crack the safe Logarithms

The questions are sourced from an A-Level textbook – why not make your own textbook tasks more interesting by creating your own safecrackers on the board? Five minutes prep = puzzle fun!