The zombie hand rising from the earth
A glove hidden under the soil in a pot, a splash of vinegar… and a hand swells up and bursts out of the ground: the Halloween experiment that makes everyone scream (with laughter).
Age : age 4+, with a grown-up
Materials
- A paper cup
- A well-sharpened pencil : To poke the little holes (grown-up's job).
- 3 tablespoons of bicarbonate of soda
- A large glass of white vinegar : About 250 ml.
- A latex or nitrile glove, black or green if possible : Nitrile if anyone has a latex allergy.
- Sticky tape
- A flowerpot and some soil : Light potting compost works better than heavy soil.
- A washing-up bowl or a tray : To stand the pot in: it can overflow.
Steps
Set the trap
- The grown-up pokes about ten little holes with the pencil in the bottom and sides of the cup.
- Pour the bicarbonate of soda into the bottom of the cup.
- Stretch the glove over the mouth of the cup, fingers pointing up, and fix it all the way round with several turns of sticky tape: it must be completely airtight.
- Put the cup at the bottom of the pot, glove pointing up, and cover it completely with soil, without pressing down and without leaving anything poking out.
- Stand the pot in the bowl.
Wake the zombie
- Gently pour the vinegar all around, onto the soil.
- Step back and watch in silence…
- The vinegar trickles down, gets in through the holes and meets the bicarbonate: the glove swells and the hand pushes the soil aside to climb out!
- If nothing moves after a minute, add a little more vinegar.
- To do it again: empty it, rinse the cup and put in fresh bicarbonate.
Vinegar is an acid and bicarbonate of soda is a base. When they meet, they make a gas called carbon dioxide. The gas has nowhere to go except into the glove: it blows it up like a balloon, strongly enough to lift the soil.
Without soil, on the table: bicarbonate in the glove, vinegar in a bottle, stretch the glove over the neck and tip it up in one go. Quicker, but less suspense.
If it goes wrong
- The glove doesn't inflate : Redo the seal with more turns of sticky tape.
- The hand stays underground : Less soil, light compost, not pressed down.
- It fizzes but nothing comes out : Pour in more vinegar, close to the cup.
Safety
- Vinegar stings the eyes: no leaning over the pot during the reaction, and wash hands afterwards.
- Watch out for latex allergies: use a nitrile glove.
- Only the grown-up handles the pencil for poking holes.