Book 3, Question 83 · Video
Why Do Barcodes Beep at the Store?
A barcode is a price tag written in fat and skinny lines. A scanner reads the pattern with light, and looks up the item in a computer. Black lines soak up the scanner's light, and
Read the full answer →What Crafty Clover says in this video
Intro
Hey there, curious minds! I'm Crafty Clover! Let's discover something amazing. Why do barcodes beep at the store?
The Big Idea
A barcode is a price tag written in fat and skinny lines. A scanner reads the pattern with light, and looks up the item in a computer. Black lines soak up the scanner's light, and white gaps bounce it back. The beep means, I read a valid code! Those stripes hide a number that names the exact product, so the cashier does not have to type the price!
Light Hits Lines
Step one: light hits the lines. A red beam or a camera looks at the stripes. Black lines soak up the light, and white gaps bounce it back!
Pattern Becomes Numbers
Step two: the pattern becomes numbers. Thick and thin bars turn into digits. Then the store database finds the matching item!
Price and Beep
Step three: the price appears, and the scanner beeps. The screen shows the item's name and its cost. A short tone says the scan worked. Beep!
A Closer Look
Let's take a closer look at a barcode! The bars are the pattern. The quiet zone is white space around them. The scanner beam sweeps across. And the digits underneath are the same code in numbers!
Quick Facts
Quick facts! Most grocery codes are UPC numbers, and they are 12 digits long. If the bars are torn, the cashier can type the numbers printed below. QR codes are square cousins that hold longer messages. And library books, airline bags, and warehouse boxes use barcodes too!
Think Like a Scientist
Now, think like a scientist! Make a secret code. Draw thick and thin marker lines on paper. Agree with a friend on a secret pattern of ones and zeros first. Can your friend decode it? How is that like a barcode?
Outro
Barcodes show us that stripes of light and dark can carry a secret number. Science is amazing! Crafty Clover can be found on Amazon Books, Google Bookstore, and Apple Books. Available for purchase or download! Bye for now!