# Lesson 4: Randomness - Instructor's Notes

This page contains some tips and suggestions for the instructor when
presenting lesson 4.

## Lesson Goals

The goal of this lesson is for the children to:

- Learn what random numbers are and how they can be used.
- Learn to balance order with chaos.
- Learn how to scale/shift to create other random distributions.

## Lesson 3 Review

Ask the following questions to remind the children of what they learned
in the previous lesson.

- What did you learn in the previous lesson?
- How much does the turtle turn to create a regular hexagon?
- How do you define a procedure that takes a parameter in Logo?

## Formal Presentation

The "big idea" in this lesson is that computers can produce random
numbers, and that this can be used to make more interesting
pictures. It is also important to learn that complete randomness
is not interesting. It takes an artful balance between order
and chaos to produce interesting pictures.

Ask the children what a random number is.
Tell them to give you an example of randomness that they have experienced.
(Hint: think playing cards, coin-flips, or rolling a die).

## At The Computer

Explain what a uniform random number is and ask how
you can use that to turn in a random direction.
Then let the kids type in the random walk program.

Explain that this is kind of neat, but it quickly gets boring
and cluttered because it is total randomness.
Give examples, like starting off with red random walk, then
deciding to add some blue random walk to balance out the
red, then deciding to add some green to balance out the other colors.
Or drawing a neighborhood of well-defined objects,
like houses and cars, in random positions, just like a
real neighborhood.

Ask the kids how to create other random numbers, like
random multiples of 10, or random even numbers.

Now explain how PICK can make this easier by letting you
define the numbers you want in advance and selecting them
from a list.
Then work your way through the RANDOMSTAR example.

Challenge the children to create a program that use
randomness to create something beautiful or cool.

Now is also a good time to ask the kids to start thinking
about some long-term project they would like to do.
The best projects are somewhat open-ended, like
"create something that embodies the word 'village".