Level-graded English lessons with reading, listening, activities, and discussion.
Lesson Info
Lesson Content
Look First, Words You Need, Read and Listen
Understanding: Understand It, Steps
Language
Chunks: Meaning, Repeat
Use It
Answers
How Does a Barcode Work?
Start Here
Look First
- What can you see?
- Where are these people?
- What is the worker doing?
Before You Read
Words You Need
Learn
Read and Listen
Play the audio while you read, or listen after you read.
You can find barcodes on food, clothes, books, and many other products. A barcode is a group of black lines and white spaces. The lines and spaces have different widths, and together they represent a number or other information.
At a store, a worker passes the barcode in front of a scanner. The scanner shines light onto the barcode. The white spaces reflect more light, while the black lines reflect less. The scanner reads this pattern of light and dark.
Next, the scanner sends the information to a computer. The computer reads the number in the barcode and uses it to find the product. It can then show information such as the product’s name and price. The price is usually not stored inside the barcode itself. This means a store can change a product’s price without changing the barcode.
Barcodes help stores identify products quickly and keep track of what they sell.
Quick Check
Understand It
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Barcodes can be found on many kinds of products.
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The black lines and white spaces are all the same width.
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A scanner uses light to read a barcode.
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What does the computer use the barcode number to find?
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Why can a store change a product's price without changing the barcode?
Order
Steps
Put the barcode steps in order (1-4).
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The scanner reads the pattern of light and dark.
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Pass the barcode in front of the scanner.
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The scanner sends the information to a computer.
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The computer finds the product and its information.
Focus On
Language
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A store can change a price without the barcode.
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A scanner can read a barcode without the product.
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Workers can find a product's price without its number.
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A store can identify products without at every label.
Build
Chunks
Meaning
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different widths
-
in front of a scanner
-
reflect more light
-
keep track of
Repeat
Listen and Repeat. Hide the text and try again.
Now Try
Use It
Talk or write. Use the language from this lesson.
Complete the Sentences
Answer the Questions
Answers
Understand It:
- True
- False
- True
- the product
- The price is not stored inside the barcode.
Language:
- A store can change a price without changing the barcode.
- A scanner can read a barcode without touching the product.
- Workers can find a product's price without typing its number.
- A store can identify products without looking at every label.
Steps:
- Pass the barcode in front of the scanner.
- The scanner reads the pattern of light and dark.
- The scanner sends the information to a computer.
- The computer finds the product and its information.
Chunks: Meaning:
- different widths: some are wider than others
- in front of a scanner: where the scanner can read it
- reflect more light: send more light back
- keep track of: know what products they sell
KEEP GOING