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Two easy outdoor science experiments for kids © Getty Images

Two amazingly easy indoor food experiments to try out with the kids

Published: 08th July, 2020 at 12:00
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Grow vegetables from food scraps, and watch mould grow in a handprint on a slice of bread.

In The Pocket Book Of Garden Experiments, author Helen Pilcher suggests a series of fun, science-based activities that you can do at home. Here are a few words from Helen:


“It’s 80 experiments that you can either do in your garden, or using things from your garden. It’s for families, but the experiments are doable, without adult interference, for most kids aged 11 and up. People younger than that will hopefully also love it, but might need a little help from a grown-up.

"It's got things like making conker soap, dyeing with avocado stones and making moss eco-graffiti. The focus is on experimenting and fostering curiosity. I'm aiming to get kids asking questions, then making and doing things to find the answer to those questions. My daughter was my very strict 12-year-old editor, who told me what should go in and what was left out!”

Here are two experiments you can do at home.

Grow plants from food scraps

Plants have such a strong urge to grow, that some plants we eat will keep on growing from the parts that we throw away. Some of them will even grow into complete new plants you can eat! See which ones you can grow on the windowsill.

You will need:

  • Glass jars
  • Plates or saucers
  • Fresh water
  • Food scraps: carrot tops, onion bases, celery or lettuce bases, leafy herb leaves

Root vegetables

For root vegetables like carrots and beetroot, you want to keep the top of the root (where the leaves attach to the vegetable), and a little bit of the root itself. To get them to grow, put them onto a saucer of water. Check every day and add more water to the saucer as it dries out.

In a few days you should see fresh green leaves growing. You can eat them. Beetroot leaves have a mild flavour and make a nice salad. Carrot leaves can be a bit bitter, so you may not like them.


For onions, you want the base of the bulb (where the roots stick out). You can use the bottom of spring (green) onions, or bulb onions, it doesn’t matter.

Pop them into the bottom of a glass jar with some water. Check on them every day and replace the old water with fresh water. Very soon you will see new roots growing from the onion base, and you may start to see fresh green leaves as well. The leaves are edible, just like chives.

Leafy greens

You can regrow leafy greens that grow from a solid section (called a ‘heart’), like cabbage, lettuce and celery. We often throw that part away because it’s tough, but if you put it onto a saucer of water and keep checking on it every day, you should find that it starts to grow new roots and fresh, edible leaves.

You can also try growing the leaves themselves. Leafy greens, and leafy herbs like parsley, coriander and watercress will often grow roots in a jar of water. If you want to, you can then pot them up into soil and they will continue to grow into larger plants.

Did you know?

Plants are very different from animals, because they can often regrow after being cut in half. They need air, water and sunlight to regrow, but they will eventually run out of nutrients unless they’re planted in soil.

Read more from Helen Pilcher:

Grow a mould handprint

The world is full of living things so small they can’t be seen with the naked eye. When they grow in vast numbers, they become visible. Watch microscopic mould growing into something big on a slice of bread and learn about the conditions needed to make it grow.

You will need:

  • Three slices of white bread
  • Three pieces of kitchen towel
  • Water
  • Three clear plastic bags
  • Masking tape

If you’ve ever opened the bread bin and found that the loaf is covered in colourful fuzz, that’s mould. Mould is a type of fungus. It grows from spores that blow around in the air, and can be found just about everywhere, including on your skin, in the soil and on work surfaces. Some moulds can make people ill, but most are totally harmless.

  1. Prepare your mould-growing bags. Fold the pieces of kitchen towel into quarters and sprinkle them with water so they are damp but not soaking. Now put one piece of kitchen towel into each of the plastic bags.
  2. Press your hand firmly into each slice of bread so it leaves a handprint in the middle. Some of the spores on your skin will be transferred to the bread. Put one piece of bread into each of the bags so it sits on top of the kitchen towel. Now seal the bags tightly shut using the masking tape.
  3. Label the bags 1, 2, 3. Put the first bag in the fridge. Put the second bag onto a warm, brightly lit windowsill. Put the third bag into a dark kitchen cupboard. Now leave your mould to grow.
  4. Check on the experiment every day. You should see mould beginning to form after a couple of days. After seven to 10 days the experiment will be done. Do not open the bag. You can study the mould from the outside.
  5. Do all of the bags contain mouldy bread? Which contains the most mould? Has it grown in the shape of a hand? What conditions does mould need to grow? Take photos and describe your results in your journal. When you are finished, ask a grown-up to dispose of the experiment in an outside bin.

Did you know?

Some moulds can kill bacteria. Penicillin is a common antibiotic that was originally discovered in mould.

The Pocket Book of Garden Experiments by Helen Pilcher is out now (£14.99, Bloomsbury Wildlife).

The Pocket Book of Garden Experiments by Helen Pilcher is out now (£14.99, Bloomsbury Wildlife)


Helen Pilcher
Helen PilcherScience writer, presenter and performer.

Helen Pilcher is a tea-drinking, biscuit-nibbling science and comedy writer, with a PhD in cell biology.


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