5 Easy Science Experiments To Do With The Kids

Education News Things To Do | by | 7th Sep 2016


This week, the prestigious British Science Festival is being held in Swansea and promises to be an exciting few days of talks, debates, performances and activities culminating in a free family weekend on September 10th and 11th.

This free weekend of community events includes a bug hub, a 3D Space Show and a chance to meet an astronaut!

Can’t make it down to Swansea? To celebrate the festival’s visit to Wales, we’ve put together a run down of five super fun and easy science experiments you can do with your children at home!

1: Diet Coke and Mentos explosion

This is a classic experiment that turns any bottle of coke into your very own exploding geyser!

What you’ll need:

  • A big bottle of Diet Coke
  • Half a packet of Mentos
  • Open space (not a living room!)


Image: Jordan Crowe, Flickr

What to do:

  • Take the full bottle of coke outside into a large open space such as a park or garden; or anywhere else where you won’t get in trouble for getting Diet Coke everywhere!
  • Stand the Diet Coke upright on the ground and take off the lid.
  • Now for the fun bit. Carefully drop the Mentos into the Diet Coke and get ready to run away! After a second or two, a large geyser of Diet Coke should come flying out of the top of the bottle! How high will your explosion be? The record is about 9 metres!

The science bit:

Diet coke, and other fizzy drinks, are bubbly because carbon dioxide is pumped into the bottle at the factory. Imagine that there is a whole load of carbon dioxide gas sat waiting to escape the bottle in the form of bubbles!

This is only released from the liquid when you pour the drink or when the lid is opened. The theory is that by dropping Mentos into the Diet Coke, the process is sped up as the sweet breaks the ‘surface tension’ of the liquid and also allows bubbles to form on the surface area of the Mentos (‘nucleation’).

If you looked at a Mentos piece under a microscope, you would see that it is covered in teeny tiny dimples (almost like a golf ball), which dramatically increase the surface area of each sweet! This allows a huge amount of bubbles to form and creates the cool explosion effect!

2: Invisible Ink

Become a secret agent for the hour and make invisible ink with lemon juice. This classic bit of household science is such a simple way for you and your children to leave secret messages around the house! 

What you’ll need:

  • Half a lemon
  • Water
  • A bowl
  • Spoon
  • Cotton bud
  • White paper
  • A lamp or other light bulb

What to do:

  • Squeeze lemon juice into the bowl and add a few drops of water
  • Use the spoon to mix together the water and lemon juice
  • Dip the cotton bud into the mixture and write your secret message onto the plain white paper
  • Wait for the juice to dry so it becomes completely invisible
  • When you are ready to read your secret message, heat the paper by holding it close to a light bulb, or a candle like in the video! Be careful not to burn yourself…

The science bit:

When heated, lemon juice reacts with oxygen (oxidises) and turns brown. By diluting the lemon juice in water and letting it dry on the paper, we make it ‘invisible’. No one will be able to see it until it is heated and the secret message is revealed!

3: Bending Water with Static

This experiment is perfect for helping kids learn about static electricity. Help them ‘bend’ water with static electricity produced simply by combing their hair!

What you’ll need:

  • A plastic comb
  • A thin stream of water from a tap
  • Dry hair

What to do:

  • Turn on the tap just a little so that the water comes out in a narrow stream. Something more than droplets but nothing that flows too wide!
  • Let your child run the comb through their hair as they normally would, around ten times.
  • Then slowly move the comb towards the stream of water (without touching it) and watch closely to see what happens! Will you bend water?

The science bit:

By combing your hair, static electricity is built up on the comb and this attracts the stream of water, creating the bending effect!

When the dry hair and the comb rub together, negatively charged particles called electrons move over to the comb. It now has extra electrons and is negatively charged overall. Positive and negative charges are attracted to each other, so when the negatively charged comb is placed near the tap, it attracts the positively charged particles in the water and the stream bends!

4: Do Oranges Float or Sink?

Have you ever seen an orange float? Or do they sink? This might be a trick question! This experiment will teach you something cool about oranges and density!

What you’ll need:

  • An orange
  • A bowl or container
  • Water

What to do:

  • Fill the bowl or container with water
  • Drop the unpeeled orange into the water and watch what happens. Does it float?
  • Now, peel the skin off the orange and try the experiment once more. What happens this time?

The science bit:

When the unpeeled orange is placed in the bowl of water it should float to the surface, but after you remove the skin it sinks to the bottom. How can we explain this?!

The skin, or rind, of an orange has loads of tiny air pockets which help give it a lower density* than water, making it float to the surface. When we remove the rind, and in turn all the air pockets, from the orange increases its density higher than that of water, making it sink!

*Density is the mass, or the amount of matter/stuff, of an object in relation to its overall volume, or the amount of space an object takes up. Objects with a lot of matter in a given volume have a high density, while objects with a smaller amount of matter in the same volume have a low density.

 5: Make a rainbow!

This final experiment produces really beautiful effects – and is a really cool way to show your children how rainbows are formed!

What you’ll need:

  • A glass of water, three quarters full
  • Some white paper
  • A sunny day (good luck!)


Image: Anders Sandberg, Flickr 

What to do:

  • Find a part of the room with sunlight coming in
  • Carefully hold the glass of water up above the paper and watch the sunlight pass through the glass of water and forms a rainbow of colours on the sheet of paper
  • Try moving the glass to different angles or heights to see what different effects you can make!

 The science bit:

Rainbows are formed when sunlight refracts, or bends, as it passes through raindrops and it acts in the same way when it passes through the glass of water! When the sunlight refracts it separates out into a spectrum of those colours we all know so well: red, orange, yellow, green, blue, indigo and violet. The white paper simply helps our eyes see the rainbow much clearer!

Do you have ideas for science-y things to do easily at home? Leave a comment below!


Want to find out about services available to you and your child in your area? Would you like to chat about family matters in general? Then get in touch with the FamilyPoint Cymru helpline.

  • Phone: 0300 222 57 57
  • Text: 07860 052 905
  • Instant message (see top of page)

We are open 6pm – 10pm Monday to Thursday and 10am – 2pm Friday & Saturday.

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