Halloween Experiments – Fun Science

Here are some Halloween experiments for you to try with your little scientists in this spooky season –

Erupting Pumpkin

You will need:

  • Hydrogen peroxide (you can buy this from most pharmacies)
  • Dried yeast
  • Washing up liquid
  • Pumpkin (carved!)
  • Cup x 2
  • Spoon

Method:

  • Make sure your pumpkin is carved (ask a grown up to help).
  • Pour your hydrogen peroxide into a cup, so the cup is half full.halloween experiments
  • Add a squirt of washing up into the cup and stir.
  • Place the cup inside the pumpkin.
  • Pour the dry yeast into your other, empty cup.
  • Fill the cup half full with water and stir until the yeast is mixed in.
  • Pour the yeast into the hydrogen peroxide and put the lid on your pumpkin!
  • Watch the foam erupt out!

The Science Bit:

  • Hydrogen peroxide has a similar chemical formula to water. Water is H2O (two hydrogens and one oxygen) and hydrogen peroxide is H2O2 (two hydrogens and two oxygens)! When the yeast mixes with the hydrogen peroxide it splits it into H2O (water) and O (oxygen), and the washing up liquid mixes with the water to make the foam! The bubbles in the foam are full of oxygen.
  • This is an exothermic reaction (a reaction that makes heat) so you may notice that the foam is warm!

Spooky Disappearing Picture

You will need:

  • A clear, sealable sandwich bag
  • A piece of paper
  • Colouring pens
  • Permanent marker
  • Clear container, big enough for the sandwich bag to fit inhalloween experiments

Method:

  • Cut your paper so that it fits flat in your sandwich bag.
  • Draw a picture on your paper with your colouring pens.
  • Place it in the bag and seal it.
  • Draw round part of your drawing, or the outline, using a permanent marker on the sandwich bag.
  • Fill your container with water.
  • Slowly lower the bag into the water.
  • If you look from above, you should notice part of your drawing disappear!

The Science Bit:

  • When you look at the water from above, the light refracts through the water, and bounces back at such an angle that we can’t see the image on the paper!

 

Inflating Ghost Experiment

You will need:

  • A bottle
  • Balloon (white is best for a ghost but any colour will do!)
  • Permanent marker
  • Bicarbonate of soda
  • Vinegar or lemon juice
  • Spoon

Method:

  • Blow up your balloon (don’t tie it!) and draw your ghost face on your balloon using your permanent marker.halloween experiments
  • Let the air out of your balloon
  • Put 1-2 teaspoons of bicarbonate of soda into your balloon. You may need someone to help you, or you could use a funnel.
  • Place the balloon to one side.
  • Fill your bottle 1/3 full with vinegar or lemon juice.
  • Carefully stretch the neck of the balloon over the neck of the bottle, but don’t let the bicarbonate of soda fall in yet!
  • When you are ready, lift the balloon up so that the powder can fall into the bottle.
  • Watch your ghost inflate!

The Science Bit:

  • Bicarbonate of soda is an alkali and vinegar (or lemon juice) is an acid. These are opposite chemicals. When you mix bicarbonate of soda with an acid they react. In this case it made bubbles of carbon dioxide!
  • Carbon dioxide is a gas and when the bubbles popped the carbon dioxide escaped and travelled up into the balloon, making it inflate.

 

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