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← Explorers ScienceAcids and carbonates15 minutesStd 3–5

The Egg That Lost Its Shell

✨ After two days the shell has vanished and a bare, bouncy, see-through egg is sitting in the jar.

Left: an egg in vinegar with bubbles fizzing off its shell. Right: the same egg two days later with no shell, bigger than its old dashed outline, held together by its thin membrane with water arrows moving in.
How it works

🧰 You need

  • a raw egg
  • a glass jar
  • white vinegar to cover the egg
  • a spoon
  • a torch

⚠️ Wash your hands after touching raw egg and never eat it.

👀 What you will see

Tiny bubbles cover the shell and a white froth collects on top. By the second day the shell has mostly gone and the egg feels rubbery and looks bigger. With the torch behind it you can see the yolk glowing inside.

🧪 Do it

  1. Lower the egg gently into the jar with a spoon.
  2. Pour in enough vinegar to cover it completely.
  3. Look after ten minutes and note what is happening on the surface of the shell.
  4. Pour away the cloudy vinegar the next day and add fresh vinegar.
  5. After two days lift the egg out and rinse it very gently under a slow tap.
  6. Hold the torch behind the egg in a dark room and look through it.

💡 Why it happens

An eggshell is made of calcium carbonate, the same material as chalk and limestone. Vinegar contains a weak acid, and an acid is a substance that reacts with carbonates to release carbon dioxide gas, which is what all the bubbles are. The shell dissolves away but the thin skin underneath, the membrane, survives and holds everything together. Water also passes through that membrane into the egg, which is why the naked egg looks swollen.

🔁 Now try this

Put your naked egg into plain water for a day and a second naked egg into very salty water, then compare their sizes.

🤔 Think about it

If a weak acid can strip an eggshell, what might fizzy acidic drinks be doing to your teeth?

🧘 Ask the Acharya

“If a weak acid can strip an eggshell, what might fizzy acidic drinks be doing to your teeth?” — ask him and he will explain it from your own chapters.

Ask Guru →

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