This lesson introduces students to the concept of Boolean logic and expressions in the context of conditional statements and decision blocks in flow charts. This lesson also ties Boolean operators to the visual concept of a Venn diagram. This presents students with multiple representations and modes of understanding.

**Complex Decisions**

One question that comes up frequently is how can computers do complex tasks such as play chess, search the web, and drive automobiles when all they can represent is 0's and 1's? In order to answer that question, we must understand logic, and in particular, Boolean logic which operates on 0's and 1's. Note that we could use other symbols for these two values, for example, `F`

and `T`

or `False`

and `True`

. Inside a digital computer, they are represented by different voltages, one high and one low. It can be represented by a switch with only two positions. It can be represented by a valve which is on or off. Daniel Hillis [1] [1] built a computer out of Tinker Toys. It is now in the Boston Museum of Science. An excellent reference for this is his book *The Pattern on the Stone* .

**Flow Charts**

Flow charts implicitly represent Boolean logic, whenever you have a decision diamond. A complex decision can involve chaining decsions or they can be sometimes combined into complex Boolean expressions.

**Bits**

You can explain the concept of bit