You will need:

  • An egg
  • A glass
  • Vinegar

What to do:

  • Fill the glass with vinegar and place the egg in the glass
  • Gently stir every few hours to remove gas bubbles that have formed
  • After 24 hours remove the egg from the vinegar with a spoon to see if the shell has dissolved
  • If not, return the egg to the glass of vinegar and for another few hours
  • Remove the egg from the glass and rinse gently with water
  • Notice that the shell has disappeared – it has been corroded by the acid in the vinegar
  • This is why we must clean our teeth regularly — to stop acid build-up from eating our teeth (our teeth are made of a similar substance to egg shells)