Six cool science experiments for kids

Mark Evans offers up some brilliant experiments that you and your kids will love. 

Somewhere on the moon there is a feather, lying in the dust surrounded by boot prints. This is a fact. How it got there was due to a man who died more than 350 years ago. This is also a fact. Both facts are linked by science, or more specifically, by the urge to find out what happens in certain situations.

According to the story, this same urge made Galileo climb the steps of the Leaning Tower of Pisa and once he was at the top he dropped two different sized balls made of the same material to prove they would take the same time to hit the ground. By carrying out this experiment the Italian scientist was debunking a notion held by most people since the time of Aristotle.

It probably makes sense to you here today that objects of unequal masses will fall with equal speed. But carry out the experiment before a child and ask them which they think will reach the ground first and they’ll probably point to the smaller of the two. Things get trickier when you show kids a feather and a piece of lego and ask them which one will strike the floor first. Most of them will know the plastic block will fall faster but won’t know the reason for the feather’s slow descent. Air resists the feather’s fall much easier than the lego block’s. According to Signore Galileo if you could take the air away, both feather and block would fall together. Now where do you know that doesn’t have any air?

Cut to 1971. Astronaut David Scott is standing on the moon, holding a 1.32kg hammer in one hand and a 0.03kg falcon feather in the other. He releases them. They fall, slowly, and hit the moon dust at the same time. “How about that,” Scott says. “This proves that Mr Galileo was correct in his findings.”

Galileo and Scott proved another thing: science can be as simple as dropping things and watching what happens. It doesn’t have to involve dangerous chemicals, or complex mathematics, or massive underground machines. You don’t have to climb towers or even leave the planet. Science can be boiled down to doing and watching - experimentation and observation.

Here’s another fact - all kids love science. They are each little scientists, young einsteins who ask their brilliant questions, build things, poke things, get up to mischief because they are innately curious about the fascinating world around them and want to know how it all works.

There’s a great push to get more students interested in science, particularly girls. We strive to create more engineers and technicians. The American astrophysicist Neil DeGrasse Tyson was once asked how can we get more children interested in science. His reply was: “Get out of their way.” Each girl and boy starts off experimenting and observing, asking questions and formulating facts. That spark somehow gets snuffed out by the time they are studying science for the Leaving Certificate. Part of the blame must be laid at the feet of society. We tell these young scientists that these subjects are difficult and abstract, attainable only by those with genius-level intellects. But the opposite is true - science is child’s play.

Parents play a crucial role in keeping the curiosity flame burning. When faced with the inevitable barrage of questions, such as “Why is the sky blue?” and “How do fish breathe?”, it’s all too easy to dodge the mini-inquisitors with an “I don’t know” or by saying something that tells the child that trying to understand nature is too hard. You’re reaction informs them much more than any answer would. If you know why the sky is blue, tell them; if you don’t, show them how you can both find out together.

Science Week offers parents and children the perfect opportunity to learn some new things and have fun while doing it. The annual event celebrates its 20th birthday this year, having grown from humble beginnings to a programme of more than 800 events right across the country. Some sold out weeks in advance, such as Scintillating Science with Dara Ó Briain at the National Concert Hall. The event answered questions such as: Why do our brains love to win? and Do you have what it takes to travel into outer space?. But there’s plenty of other entertaining offerings for the week.

To keep your young einsteins happy, we’ve prepared six experiments they can perform at home. There’s simple tricks like making metal float on water and messy ones that we advise you to conduct outside. Our favourite is the one that allows you to measure the speed of light by using a chocolate bar and a microwave oven. It’s the perfect blend of observation and experimentation, and your junior Galileo gets to eat the tasty results.

If you can’t go along to a Science Week event then bring some science into your home. It will add fuel to your kids’ burning desire to find out how the universe works. It will let them see that science can be fun, much like playing, in fact. And who knows, maybe science will give them a career that is out of this world.

Don't forget! If you try any of these experiments at home, take a video be sure it send it into us. Email


Make a paperclip float on water.

What you need:

  • A paperclip

  • Some tissue paper

  • A pencil/pen.

  • A bowl of water.

What to do:

  • Tear some tissue and place the paperclip at the centre.

  • Hold the two edges of the tissue and gently lower it onto the water.

  • Carefully prod the tissue with the pencil until it sinks, leaving the paperclip on the surface.

How it works:

This is all about surface tension. The water atoms in contact with air behave like an elastic, allowing the paperclip - and, in nature, some insects - to float.


Make a chemical reaction eruption.

What you need:

  • Baking soda, also known as sodium bicarbonate.

  • Vinegar.

  • Plastic bottle.

  • Red food colouring.

What to do:

  • Spoon some of the baking soda and a few drops of colouring into the bottle.

  • Pour a good dollop of vinegar into the bottle.

  • Stand back and watch the volcano erupt.

How it works:

Vinegar is acetic acid and baking soda is a base. When an acid and base meet they cause an unstable chemical reaction that releases lots of carbon dioxide, which fizzes out of the bottle.


Use air to propel a balloon along a track.

What you need:

  • 10 metres of string.

  • Some long balloons.

  • A straw.

  • Some sticky tape

What to do:

  • Thread the string through a straw then secure both ends as far apart as you can.

  • Blow up the balloon and stick it to the straw at two places.

  • Make sure the string is as taut as possible.

  • Let go of the balloon and watch it go.

How it works:

Newton discovered that every action has an equal but opposite reaction. The air leaving the balloon propels it forward in the same way as a space rocket works.


Turn a piece of iron into an electromagnet.

What you need:

  • A large nail.

  • Some plastic-coated wire with the wire exposed at each end.

  • A square battery - the ones with the terminals on top.

  • Some metal objects containing iron.

What to do:

  • Tightly wind the wire around the nail. The more you wrap the stronger it’ll be.

  • Connect the exposed wire ends to the battery terminals to form a circuit.

  • Use the point of the nail to pick up the metal objects.

  • Disconnect one of the wire ends from the battery to turn off the electromagnet.

How it works:

When electricity flows around the nail it causes the metal to behave just like a magnet.


Cause a gas explosion with messy results

What you need:

  • A packet of Mint Mentos sweets.

  • A large bottle of diet cola.

  • A thin plastic tube to allow the sweets slide into the bottle.

What to do:

  • Put the sweets into the tube. The more, the better.

  • Pour the sweets straight into the cola bottle.

  • Get out of the way.

How it works:

When you open the bottle, the carbon dioxide (fizz) locked in the cola forms bubbles on microscopic blemishes on the plastic. Mentos sweets are coated with hundreds of crystal ridges, which offer the CO2 plenty of places to form bubbles very quickly. The sudden release of gas forces the liquid out in a huge geyser of cola.  

6) E=m(icrowave) x c(hocolate)2

Measure the speed of light with chocolate and a microwave oven

What you need:

  • A chocolate bar

  • A plate

  • A ruler

  • A microwave oven

What to do:

  • Take the rotating plate out of the microwave and place the upturned plate inside with the chocolate bar on top.

  • Turn on the microwave until you see the chocolate begin to melt.

  • Carefully take out the chocolate and measure the distance between the two melting points.

  • Multiply that distance by two and multiply that sum by 2.45 billion. Then divide by 100 to get the speed of light in metres per second.

How it works:

Microwaves are a form of light and travel at the same speed. The two melting points on the chocolate show where the microwaves enter and exit. The distance apart should be around 6cm.

You multiply that by two to get the full wavelength. Since the speed of a wave equals its wavelength by its frequency, you multiply the sum by 2,450,000,000 because most microwave ovens operate at 2.45GHz (which is the speed the waves bounce up and down).

You should get an answer close to 300,000,000 metres per second, which is the speed of light.

READ MORE: Put your scientific knowledge to the test with our quick quiz


  1. Science Workshops & Tours at CIT Blackrock Castle Observatory. All week.

  2. Get a taste for science at Alimentary Adventures and learn all about digestion. Free, but pre-booking necessary. November 16, 10am-2pm at UL.

  3. Go on a guided tour of the night sky at Institute of Technology Tralee. November 18, 7.30pm-10.30pm.

  4. Get blown away by the London Science Museum’s Bubble Show. Waterford Institute of Technology, November 16, 9.45-10.45am. 051-302039

  5. Irish scientist Dr Niamh Shaw performs To Space, a funny memoir and lecture at Smock Alley Theatre, November 17, 8-9.30pm.

  6. MathWorks Mobile promises stimulating and fun introduction to maths through the use of puzzles and games. All week at the Lifetime Labs, Cork.

  7. Science Rising at Cork City Hall is free but pre-booking is necessary. Fun events for all ages and interests. November 19, 11-8.30pm.




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