Sunday, November 29, 2009

Classroom Jeopardy!

I created a review game with this online tool today:

If you want to play it, here it is.

Tuesday, November 17, 2009

Position, Velocity, Acceleration

My students asked how you could have positive acceleration but negative velocity. The spacebus holds the answer: click on the bus, then use Page Up and Page Down keys.

Wednesday, November 11, 2009

The rational number line

I ran across this diagram on another math site recently:


It's a good diagram, but a little misleading.  Between any two rational numbers is another rational number, so the rational number line would appear to be solid at any given magnification.  The fact that there is "room" for the irrationals continues to amaze me.  The fact that the irrationals are even more numerous than the rationals is inconceivable to me.

Tuesday, November 3, 2009

The cone problem

Here's a problem that I cooked up today to puzzle the math team.


You must slice a cone parallel to the base to create two pieces such that one piece has twice the volume of the other.  If the cone has a height of h, where do you make the slice?  There are two answers.