Glowing Rubber Egg

Soak a raw- egg in vinegar and highlighter ink to transform it into a fluoro bouncy ball!

Suitable for kids aged 4+ with parental supervision


You Need:

  • Raw egg
  • Glass or jar, big enough to hold the egg
  • Vinegar
  • Highlighter ink for highlighter pen (this may require some pliers)
  • Ultra violet torch (otherwise known as a black light)

What to do:

  1. Place the raw egg in the glass or jar.
  2. Pour enough vinegar into the jar to completely cover the egg. Look closely, what do you see? Can you see some tiny bubbles start to form on the shell? Why?
  3. Extract the ink from a highlighter pen, squeeze this into the vinegar (this may require the use of pliers).
  4. When the shell has completely dissolved, after about 3 days or so, remove the egg from the jar and gently rinse it with tap water. How does it feel?
  5. Bounce your new rubber egg on a hard surface. How high does it bounce?
  6. Shine the UV torch on the egg and watch it glow in the dark!

Why is it so?

Vinegar is a weak acid (acetic acid) and reacts with the calcium carbonate eggshell to produce carbon dioxide gas (hence the bubbles that form). Eventually the calcium in the eggshells is completely broken down by the acid and becomes a soft rubbery texture.You will know the hard shell has completely reacted with the vinegar once the bubbles of carbon dioxide gas stop forming. Also, try vinegar of different concentrations diluted with water, or different acids such as citric acid.