Engineering: Binary Code Grade Range: Elementary School, Middle School, High School Format: Hands-on

This is a student-interactive demonstration, which can be set up with a poster next to it with directions. It is designed to let students try it on their own and figure out the pattern used, but keep someone near the demonstration so the students can ask questions if they have any.

## Materials

• Binary Board
• Ping Pong Balls
• Optional: Explanation Poster

## Safety Precautions

Please read the General Safety section of the Demonstration Safety page before performing this demonstration.

## Demonstration

1. Set up the board, making sure that both legs are pulled out to provide balance. If you brought one, set the explanation poster next to it.
2. Allow students to try and work the board themselves, sliding the knobs to adjust the blocks inside and dropping the ping pong ball to see what value they get.

## Why This Works

Binary Code is the base code for computers. by opening and closing a tiny switch called a transistor, the computer will transmit either a 1 (open) or 0 (close). In binary, a computer will have a line which is filled with 1s and 0s, and based on where in the line the 1s are at determines what value the entire line has. Starting with the rightmost number, each number is equal to twice the value before it. So, if you saw a line with four numbers, like 1111, then the first 1 would be "1", the next 1 would be "2", the third 1 would be "4" and the last 1 would be "8". You would then add the values together to get the value of the number line, in this case it would be 1+2+4+8 = 15. If any of the numbers are 0, then you ignore that value. So if our line was 1101, then we would add 1+0+4+8 = 13. With our binary board, we are adjusting the values for a line with only three numbers. By sliding the bars between 1 and 0 we are replicating the transistors in a computer, and can see how opening and closing them gives us individual numbers.