Tuesday,  March 9

Projects : Do you have an approved project with partners?
Do you have a plane on how you'll use the time of the break for your project?

Kieval Lecture

### "The Mysterious Arithmetic of Knots"

on Thursday Evening- 7:30 pm FH 118 by John Conway

You can get knot models by clicking on a picture in the Knot Zoo or by using a simple knot viewer (randomly chosen).

.... From John Conway (et al.) 's web materials on Geometry and The Imagination

# Knots

A mathematical knot is a knotted loop.
For example, you might take an extension cord from a drawer and plug one end into the other: this makes a mathematical knot.

It might or might not be possible to unknot it without unplugging the cord. A knot which can be unknotted is called an unknot.

Two knots are considered equivalent if it is possible to rearrange one to the form of the other, without cutting the loop and without allowing it to pass through itself.

The reason for using loops of string in the mathematical definition is that knots in a length of string can always be undone, so any two lengths of string are equivalent in this sense.

If you drop a knotted loop of string on a table, it crosses over itself in a certain number of places. Possibly, there are ways to rearrange it with fewer crossings--the minimum possible number of crossings is the crossing number of the knot.

Make drawings and use short lengths of string to investigate the following problems.

### Problems for porfolio entry on knots:

1.
Are there any knots with one or two crossings? Why?
2.
How many inequivalent knots are there with three crossings?
3.
How many knots are there with four crossings?
4.
How many knots can you find with five crossings?
5.
How many knots can you find with six crossings?

Continuing with Similarity.

Similarity and Editing- font size applications.

Wingeometry similarity.

Rubber band activity.

Arithmetic and Geometric Series
.