- What’s Inside a Scratch-Off Label: Why Can You Scratch It Off So Easily?
Have you ever scratched off your name on a delivery sticker or played a scratch-off lottery ticket? Sometimes, using a pen doesn’t work, but scratching with your fingernail removes the words. That’s the magic of scratch-off labels. The secret is in the thin layers of the sticker.
Scratch-off lottery tickets also use this same idea — the mystery and surprise of scratching make people feel excited and curious.
The Secret: A “Sandwich” of Three Layers
Scratch-off labels look like one piece of paper, but they have three parts:
Top Layer: A protective layer.
Middle Layer: The message layer, with hidden text or images.
Bottom Layer: The base layer, usually a piece of paper.
The middle layer is the most important. It has two parts:
Top part: A cover material, like wax or special ink, that hides the message.
Bottom part: A color layer, which holds the real text or color.
Before scratching, the cover hides the message completely. When you scratch with a fingernail or coin, the top cover breaks, and the hidden color or message shows.
- Soft vs Hard Materials: Why Scratching Works
Why does scratching work so easily? It’s because of how soft or hard the materials are:
Cover materials (like wax or soft resin): These are soft and break easily when scratched.
Color materials (like ink or graphite): These are harder and more stable. They stay in place even when the soft cover is removed.
When you scratch:
The soft top layer breaks or gets pushed aside.
The hard bottom layer stays and either shows its color (like white paper), or changes color from heat or pressure.
Some materials even change color with friction, making the message appear as you scratch.
What Happens During Scratching?
Let’s look at what really happens — in just a few seconds — when you scratch a label.
Step 1: Pressure Breaks the Top Layer
When you press a coin on the label, the force is focused on a small spot. The top layer (like wax or soft ink) breaks or moves aside. Think of poking tofu with a chopstick — soft things move or break easily.
Step 2: The Message Appears
There are two main types:
Physical reveal: The top black or silver layer is scratched off, and the bottom white or colored text is shown — just like correction fluid covers writing.
Chemical change: Some use heat-sensitive ink or friction ink. When you rub them, they get hot and change color. Others use tiny capsules that break and mix colors when scratched.
Step 3: The Change Can’t Be Undone
Once scratched, it can’t go back to normal. The top layer is broken into small pieces or melted, so it can’t cover the message again. Just like broken glass can’t be fixed, a scratched label shows that the information has been revealed — forever.
Scratch Labels in Daily Life: Smart Uses
Scratch-off technology is used in many places, not just on delivery stickers.
Food Packaging and Prize Games
You might see this on bottle caps or snack packs:
Top: Silver or black ink covers a message like “You Win!” or “Try Again.”
When scratched: Your fingernail or coin removes the top ink and shows the message underneath.
The top ink must be thin and easy to scratch. The message underneath must be strong and not get damaged when scratched.
