The appliance of science: home experiments with your kids

With Science Week starting on Sunday, what’s the best way to make science engaging for children and start a journey of discovery together?

‘Why is the sky blue?’ Have you ever had that question thrown at you from the back of the car? Could you answer it with confidence? Questions like these are a great way to start a conversation with your children about science, and you don’t need a PhD to do it.

Margie McCarthy of Science Foundation Ireland says that the questions children ask from a very young age provide the perfect opportunity to start a journey of discovery together. If you don't know the answer, find out together, she says.

“I’ve a five- and seven-year-old and the questions they ask will get the conversation going. I have an engineering background and sometimes I am stumped. The important thing is to be open to the conversation. Go and find out how the toaster works if you don’t have the explanation. It could be the beginning of a very interesting journey for you too.”

Next week is Science Week, and one of the messages that McCarthy is hoping to put out there is that science is for everybody, not just those hoping to work in the sector. Helping your child to become science-literate is a great gift.


“Science is so much a part of everyday life,” she says. “In the kitchen, the bathroom and in the garden, there are so many opportunities to turn the conversation to science. You don’t need to have the information to hand: have the confidence to go on the search with them. It can seem daunting if you don’t come from a science background, but even as an adult it’s important to be aware of what’s going on in your world that is so heavily reliant on science, engineering, maths and technology concepts.”

Non-specialist background

In some respects it’s easier to explore science with children if you’re coming at the subject from a non-specialist background, says McCarthy. “When I go through maths homework with my seven-year-old, I sometimes find it hard to go back to her level.”

One of the big problems for children of school-going age is that they can’t always make the link between what they learn at school and everyday life. If you as a parent or teacher can help them to connect science to their natural curiosity, you’ll be making a great start. If, for example, the child is drawn to the colours in the garden, you can turn that wonder into a conversation about biology. If a child loves to bake, it can lead to conversations about chemistry. A rollercoaster ride leads straight to physics.

“Because I have been in this career for so many years, I grab any opportunity to lead children in to it,” says McCarthy, who worked as an environmental engineer for 10 years before taking on the role of head of education and public engagement at SFI. “You can answer a question with a question. Why do you think flowers are so colourful? Then go and find out together.”

It’s important to remember that pinpoint accuracy is only really important for homework. Inspiration is what matters, says McCarthy. “The fear of being wrong knocks some adults’ confidence. It’s more about raising the interest level of the child and inspiring her or him to keep exploring.”

So, now you're talking. The next step, says McCarthy, is to try some experiments at home or school. "It doesn't have to be messy and it doesn't have to be expensive. Many engaging experiments can be done with stuff around the house. The best resource for home experiments is"

As an engineer, one of Margie’s favourites is an experiment she does with uncooked spaghetti and marshmallows. It is designed to get children thinking about engineering and the roles of different shapes in building. She says the story you attach to the experiment is key, especially when dealing with the very young.

Chocolate bunnies

“I get my girls to build little rabbit hutches for chocolate bunnies. They try different shapes and different combinations until they find the strongest structure possible. Which is stronger, a square or a triangle? A pyramid or a cube? How strong are single strands linked by marshmallows, as opposed to bunches? They place rulers on top to see which resists the most weight. These are basic maths and engineering concepts that they’re learning, and they enjoy it because of the way it’s presented.”

Such activities inspire new questions and new conversations, says McCarthy, and not just “when can I eat this bunny?”

“The fact that you are showing interest sends out a strong message to children that science is for everyone. ”


White light from the sun is made up of a mixture of all the colours of the rainbow. The colours come in waves. Red comes in long waves, while blue waves are very short.

The Earth is surrounded by an invisible layer called the atmosphere. It’s kind of like a forcefield. It keeps the clouds in and space out. The atmosphere is made up of tiny little things called atoms. They are so small, we can’t see them (actually everything is made of atoms, but that’s for another conversation). The atoms in the atmosphere have names such as oxygen and hydrogen.

When the white light from the sun passes through this layer of atoms, some of the lightwaves bounce off the atoms, like water bouncing off a ball. Blue waves bounce the most, because they are particularly wiggly, with short little waves. As the blue light waves bounce around between the atoms in the sky, we see all that blue light scattering around in the sky, and that is why it looks blue.



There are lots of simple experiments you can do with very young children. Start with their interests, whether it’s food, nature, weather or how stuff works. Their questions should be your first clue.

Try putting white carnations or a stick of celery in ink and see how the colour feeds up to the petals or leaves. It shows small children how plants draw nourishment up through the stem and can also start a conversation about human biology. To follow up the conversation check on the online worksheet at

To get small children thinking about what everyday stuff is made of, try making butter. All you need is some cream and a jar with a tight lid. See how it's done at

Kids are always fascinated by big weather events. Try making a tornado in a bottle with some food colouring, glitter and water, using the guide at

Primary pupils

Once your children get into primary school, their interests widen, and you have many more opportunities to link everyday life and science. If they love rollercoasters, why not figure out the physics? “I have spoken to kids about the use of maths, specifically parabolas, in rollercoaster design,” says Margie McCarthy. “I tell them that maths is what the imagineers in Disney are using when they create thrilling rides.”

Food is a great topic. A cereal box provides all sorts of great data for analysis, says McCarthy. “What are the different measures of proteins and carbohydrates? How much of our daily allowance of sugar have we had at breakfast? These calculations all add up to scientific inquiry. The important thing is to help them realise they are doing maths all the time and they are good at it. We have to do away with the idea that it’s cool to say, “I’m no good at maths”.

To get them thinking about physics, try the home experiment in energy and forces at By making their own windmill, kids are getting to grips with ideas of energy and it can form the basis for a conversation about the environment.

This is a great time of year for outdoor scientific inquiry. Primary-school children and parents can learn a lot from autumn leaves. Try hunting for the leaves of various trees and matching them against a guide. The Irish Natural Forestry Foundation has a wonderful printable chart for this at

Postprimary pupils

This can be the hardest group to start a conversation with for the first time, especially if they have already developed a negative attitude to science or have decided it is not for them. Again, it’s vital to follow their interests. Gaming is the obvious one: if a child is very interested in computers, he or she may be more likely to follow an interest in coding or technology in general.

"For a teenager, it's important to find inspirational role models," says McCarthy. "Jamie Heaslip is the ambassador for Science Week. He's from a mechanical engineering background and he sees such value in having scientific literacy. Some in that age group swill already have begun to build up a stereotype of the scientist as a geek. You need to show them that all sorts of people work in science, technology, engineering and maths."

McCarthy suggests getting teenagers along to an event such as the Festival of Curiosity next July (, where they can enjoy a whole range of activities suited to older teenagers.

“Even if they don’t want to study science at college, we want to encourage teenagers to study science subjects at secondary level. We need them to get the message that science is for everybody. Here’s an important fact for anyone in school today: five of the top 10 jobs listed on LinkedIn did not exist three years ago. The message is: you don’t know where you might end up working, so don’t close science off as an option.”

Students can also visit and read the career stories of people working in a range of interesting new areas.


Experiment 1: Design a rocket

What you’ll need

  • Large, long balloons (round ones work, but long is more rocket-like)
  • Balloon pump
  • 3m or 4m of string/fishing line Drinking straw
  • Clothes peg
  • Sellotape
  • 2 chairs

What to do

  • 1: Blow up a long balloon and let go. The balloon will zip around as the air rushes out.
  • 2: Pull the string through the drinking straw. Tie the string to two chairs and pull it tight.
  • 3: Blow up another long balloon and use the peg to keep the air in it.
  • 4: Next, tape the balloon to the side of the straw.
  • 5: Pull the whole thing back to the beginning of the string, take off the peg, and launch your rocket.

What happens?

The air coming out of the back of the balloon pushes it forwards. This is how rockets work: the burning gases rushing out of the back of the engines push the rocket into the sky and on to space. Did you ever wonder how plants “drink” their water? Plants don’t have any mouth, but like us they do get thirsty. Let’s investigate.

Experiment 2: How do plants drink?

What you’ll need

  • 1 white carnation
  • 1 stick of celery with leaves
  • Red food colouring
  • 2 glasses or plastic cups
  • Water
  • A marker

What to do

  • 1: Half fill each glass with water.
  • 2: Add enough red food colouring to the two glasses of water to make two dark red glasses of water. You now have two glasses of red water.
  • 3: Cut the stem off each plant about 1cm from the end.
  • 4: Place the celery stick into one glass of water as in the diagram.
  • 5: Place the white carnation into the other glass of water as in the diagram.
  • 6: Mark the level of water in each glass with your marker. Leave the two glasses for a day or two on a shelf. Regularly check the glasses to a see what is happening.

What happens?

The carnation’s flowers turn red. Also you will see thin red lines of coloured water running the length of the celery stalk. You will also see red in the leaves of the celery. The level of water in both glasses will have dropped. This is because the coloured water from the glasses has moved up through the thin tubes in the plants. (You can see these in the celery.)The water is then transported around the petals of the carnation and leaves of the celery. Ask an adult to cut through the celery stick. You will see the inside of the thin tubes marked red. If you have a magnifying glass, use it to look at the spot where you cut the celery.

Experiment 3: Tornado in a bottle

We have all seen films with tornadoes in them. Most tornadoes look like a funnel of cloud and dust travelling at high speed along the ground. Inside the tornado wind may be swirling at 300km/hr. It can be strong enough to lift cars, uproot trees or flatten houses. Most tornadoes last for no longer than an hour, although they aren’t common in Ireland.

What you’ll need

  • 2 2-litre clear plastic bottles
  • Water
  • Food colouring
  • 1 teaspoon of glitter (optional)
  • Water
  • Packing tape or duct tape

What to do

  • 1: Fill one of the plastic bottles about half full of water.
  • 2: Add a couple of drops of food colouring.
  • 3: Add about a teaspoon of glitter to the coloured water. The glitter represents the dust in the tornado.
  • 4: With the packing tape and help from a friend, tape the top of the empty bottle to the top of the bottle with the water.
  • 5: Make sure the tape is secure around the bottle tops, as we don't want any water leaking out.
  • 6: Turn the bottles around, making sure the bottle with the water in it is on top.
  • 7: Watch as the water flows from the top bottle into the bottom bottle.

What happens?

The water flows slowly from the top bottle into the bottom bottle. Also, air bubbles travel up through the water in the top bottle, making a noise.

Hold the bottles where they are connected and quickly swirl them in a circular motion for a few seconds. Stop and look inside the bottles.

There’s a mini tornado in the top bottle as the water flows quickly and quietly into the bottom bottle. This is because the circular motion of swirling the bottles caused the water to flow in a spiral down into the bottom bottle. Air from the bottom bottle can move more easily to the top bottle.

Older children could:

  • 1. Time how long it takes for the water to flow from the top bottle into the bottom bottle without rotating the bottles.
  • 2. Then time how long it takes the water to flow from the top to the bottom bottle after rotating the bottles.