What you need:
•raw egg (at room temperature)
• thumbtack
• skewer
• drinking straw
• bowl
• white vinegar
• a glass
• tongs
• baby powder (or cornstarch)

What you do:
• Hold the egg over a bowl and use a thumbtack to pierce a small hole in the pointed end and a larger hole in the other end of the egg.
• Hold the egg very gently to make sure you don’t crack it!
• Use a skewer or unfolded paperclip to carefully break up the yolk inside of the egg.
• Hold a drinking straw over the smaller hole and blow through the opposite end of the straw.
• Run a little water inside the egg and shake it out.
• Use the straw again to blow out any remaining water.
• Place the egg shell in a glass and add enough vinegar to cover the egg.
• Using your fingers or a pair of tongs, gently hold the egg under the liquid until the air escapes and most of the egg shell stays below the surface (this may take several minutes).
• Leave the egg in the vinegar for several hours until the shell begins to break down.
• When the shell has started to break away, you will see a flexible egg shaped layer inside—this is the egg membrane.
• Once the egg shell has completely dissolved, remove the membrane from the glass of vinegar.
• Rinse the membrane in water and gently squeeze it to remove the water from inside.
• Pat it dry with a paper towel.
• Continue tossing until the whole thing has inflated like a balloon.
• Once it has inflated, sprinkle a little baby powder all over the outside.
• Try to get some powder inside as well as it will prevent the sides from sticking together and help the egg inflate more easily next time.
• Set the powder-coated inflated egg on the palm of your hand and press the air out with your fingers.
• Fold the egg in half several times and pinch it slightly so it stays folded, then toss it between your hands again and watch it reinflate! This process of folding and tossing can be repeated several times until the egg membrane dries out and won’t inflate.