How Do Barcodes Work? | Easy English Reading

At the supermarket, a box passes over the scanner and the price appears on a screen. What did the scanner read? Follow one box of cereal from the scanner to the receipt.

Reading level: A2–B1 · Word count: 196 · Topic: Everyday science

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Reading Passage

Turn a cereal box around. On one side, you can see black lines with white spaces between them. This pattern is called a barcode. The lines and spaces have different widths. Together, they stand for a number.

At the checkout, a scanner reads the barcode. Some scanners shine a light on the code. Others use a camera. The scanner reads the pattern and sends the product number to the checkout computer. The beep often tells the cashier that the scanner has read the code.

The checkout computer uses that number to look up the cereal in the store's list of products. It finds the name and the price, then adds the cereal to the bill. The price comes from the store's computer. If the store puts the cereal on sale, it can change the price in its list. The box can keep the same barcode.

Now imagine two boxes of the same cereal, one small and one large. Each size has its own number, so the checkout computer can tell the boxes apart. Two small boxes carry the same product number. When both boxes are scanned, the receipt can show two boxes of the same cereal.

Key Vocabulary

Word	Meaning
pattern	an arrangement of marks, shapes, or colors
barcode	a pattern that a machine can read to identify a product
scanner	a machine that reads printed marks or images
look up	to find information in a list or on a computer
receipt	a slip or message that lists what you paid for

Reading Questions

1. What do the black lines and white spaces stand for?
2. What does the scanner send to the checkout computer?
3. Where does the checkout computer find the price?
4. Does the store need a new barcode when it puts the cereal on sale?
5. Why do the small and large boxes have different product numbers?

Answers

1. They stand for a number.
2. It sends the product number.
3. It finds the price in the store's list of products.
4. No. The store can change the price in its list and keep the same barcode.
5. The two numbers help the computer tell the sizes apart.

Short Summary

A barcode gives the checkout computer a product number. The computer uses the number to find the name and price in the store's records.

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