STEM与日常科技·英语30篇（6）

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二维码如何让日常物品变身信息枢纽

A QR code is a two-dimensional barcode that stores text, URLs, or contact details in black-and-white squares.
Unlike traditional barcodes, it can hold over 4,000 characters and be scanned from any angle.
When you point your phone camera at one, the device decodes the pattern using image recognition software.
Many museums now embed QR codes beside exhibits to link visitors to audio tours or historical videos.
Restaurants use them on table tents so diners can view menus, place orders, and pay digitally.
Farmers print QR codes on fruit labels to show harvest date, origin farm, and pesticide test results.
These codes don’t require internet to store data—but linking to live content does need connectivity.
Security-conscious designers add digital signatures to prevent tampering with the encoded URL.
New versions like QR-Max support offline content delivery using Bluetooth LE fallbacks.
In essence, QR codes bridge physical objects and digital knowledge—no app download required.