Christmas wishes…

Just found out what I want for Christmas! I have seen many great reviews, blogposts and opinions about this one. 1008 pages, but it seems the price and content is worth it!

 

 

Play.com (UK) : The Princeton Companion to Mathematics : Books – Free Delivery.

A tiny triangle theorem

A very small post about a tiny theorem. I found this in the excellent book Proofs without Words.

http://www.geogebra.org/en/upload/files/Norwegian/oisteing/blog/A_tiny_theorem_of_a_hypotenuse.html

The imaginary number of the beast

The centers of a triangle

There are many points competing for the title. What is the center of a triangle? In this dynamic page I gather the five most common contenders. I also throw in some circles and other points as well, trying to cram as much info as possible into this very page.

Oh – and it’s Norwegian, I thought Obama might like it

(If anyone nags me about it, I’ll make a translation!)

Look here: http://www.geogebra.org/en/upload/files/Norwegian/oisteing/trekantsenter.html

Believe

A really nice motivational video for teachers. By way of @ghveem on twitter.

Some GeoGebra examples

Just thought I should share some good examples of visual mathematics with you.

The first one comes from David Richeson, and pictures what happens when the rays striking a parabola do not come at a straight angle to the vertix.

The second one is from the excellent blog Lessons taught, lessons learnt. It shows some of the statistical capabilities of the new version of GeoGebra.

Toilet Thoughts on Learning

I remember once, when attending confirmation training, we were forced (mildly, I should add) to learn the ten commandments by heart. Me being godless already at the age of thirteen, I thought this was a rather meaningless activity, but played along just to please grandparents and others. I digress – the point not being my own attitude towards the ten laws noone is capable of living by, but rather how the priest wanted us to learn them.

Take this cheat sheet with you, and sit in the bathroom, preferably in the toilet.

As absurd as the ten commandments were, this last statement proved to be much more vital to me. The priest’s words making a deeper impact than God’s.

And it works. I can’t think of any better quality study time than the lonesome toilet scenario.

There are, of course, a lot of authors who have appreciated the toilet serenity. Even the guys at MAD magazine have their own Bathroom Companion (the turd in the series). Another favorite of mine is the Great American Bathroom Book, or GABB. In three volumes, they gather single-page (single sitting) summaries of all time best selling books.

At work, I have started the secret toilet-exercise-tournament. I print out A4-sized pages with a mathematics problem printed in large lettering on it. PowerPoint is a nice and easy way of making these poster pages. I am thinking of laminating them, in order to… you know, avoid incidents.
The current problem is this one (I think I read this in a lovely little book by Mike Ollerton, perhaps it was 100 ideas for teaching mathematics):

On a 2×2 grid of dots, you can draw one quadrilateral only. The square. How many quadrilaterals can be drawn on a 3×3 grid of dots?

I have so far just started to deploy these sheets on the toilets, so the ideas keep coming. Perhaps the exercises or problems could be more toilet-oriented (“How many sheets of paper…”,  “what will the radius of the paper holder be…”, “How big is the proportion of people who prefer the toilet paper end to hang on the inside instead of on the outside” etc…)

To be kind to the toilet-goers, you could consider leaving a stash of post-it notes and a pencil available.  Or make a bigger competition out of it; Stick problems on ten toilets in the school, who will be the first one to solve them all…

Suddenly the character “Shitbreak” from American Pie sprung to mind, so perhaps all these toilet exercises will be too weird for a lot of people, I don’t know. Right now it seems like a fun thing to do. If not THE right thing to do.

I will appreciate any suggestions for toilet exercises in the comments. (Pictures are from the flickrCC site). Have a nice weekend!

The problem with PowerPoint

From BBC News (shouldn’t this be rather old news?) comes a nice look into the 25th anniversary of PowerPoint.

The semester just started, and soon the freshmen and later-hopefully-to-be teachers are pouring in by the hundreds. Sitting on the lawn, knocking on our office door, asking good and dumb questions (they are human beings, almost like us!) and equipped with volleyballs and beer cans. Ready to take on the world.

These students are approx. 19 yrs old. They are to become teachers in four yrs time. They haven’t lived a day of their lives without PowerPoint existing in their world. And still we find teachers trying to pretend the whole PowerPoint thing never really caught on. (Hard to argue with the number of presentations held every minute…)

Personally, as a mathematics lecturer, I tend to appreciate that linear thinking is reeeeeeeeeeeally not the way stuff happens inside our brains. Textbooks and teachers try to persuade us to think this is the way mathematics came about. Not so. Hence, I have gotten into the habbit of having a slide no.1 stating just that “Where do we go from here”, equipped with a mindmap or something similar.

So Happy Birthday PowerPoint. May you NOT try to change our thinking in linear, often bad, ways, but rather help us convey ideas in meaningful and creative ways.

Read the article at http://news.bbc.co.uk/2/hi/uk_news/magazine/8207849.stm

Social media movies…

Surface Area and Chocolate

Of course, you don’t need an excuse to use chocolate and sweets in mathsclass, but just in case, here’s one:

http://mathsclass.net/comments/surface-area-and-chocolate/#When:00:10:21Z