Applets are small, single-purpose computer programs, usually available on the Web through a browser. For this site, I built the applets in GeoGebra, with the goal of making various mathematical ideas more visual and more interactive. (Tech note: how I build the applets.)
However you cannot expect them to teach the concepts they illustrate! They are most effective if they are part of a multidimensional pedagogy that gets students to engage intellectually rather than watch passively. (Blog post: Seeing is Believing?)
You can use the applets online, and/or download the corresponding GeoGebra files and modify them to better fit your needs.
Each link below is to a single applet, or to a launch page with links to several applets, or to an article where applets provide the illustrations.
Algebra
Changing a, b, c in `y=ax^2+bx+c`
Complex Number Arithmetic games
Constant Sums, Constant Products
Factored Form of a quadratic
Off and On, understanding linear inequalities
Stairs, slope puzzles
Trinomial multiple representations
Arithmetic
Signed Numbers games
- Fractions
- Pie Slices
- The Well-Chosen Rectangle
Functions
Doctor Dimension, exploring rate of change
Function Diagrams, a parallel axes representation
- Iterating Linear Functions:
- with a table
- with linked function diagrams
- with a 'cobweb' graph
Iterating `f(x)=rx(1-x)` in two representations
Geometry
Only four kindsSSASum of the Angles in a Triangle
Tri, Tri Again (inscribed circle iteration)
Virtual Manipulatives
Other
Pent, a two-person strategy game
Penumbra, some of the geometry of eclipses
Spirograph, exploring symmetric figures created by a circle in a circle
As I create more applets, I'll try to remember to add links in this directory.
