How many calories? and the way the kilogram was defined has been in place since 1799. It recently got a makeover.

We explore how to find the equations for a spiral around a hyperboloid.

Infinite series have played an important role in the development of mathematics, especially calculus. Here's some background to some applets I wrote recently.

This object has a weird property - it has finite volume, but infinite surface area. How is this possible?

The revised double spring applet now allows exploration on mobile devices. Here is some background.

Explore piano note frequencies in this interactive learning object, combining trig graphs and exponential growth.

y = ax² + bx + c is a parabola. Changing the variables a and c are fairly simple, but what does b actually change, and by how much?

This interactive applet allows you to explore the concepts of domain and range for several different mathematical functions.

Self-taught mathematician and astronomer Benjamin Banneker excelled despite little formal education and prejudice.

Here we solve another graph mystery - what is the correct domain for y = sec(arccos(x))? And why do different software packages show similar, but different graphs?