5 fun science experiments to do at home
23 April 2020
Nature is an extraordinary playground for those who know how to open their eyes and want to discover its secrets. And that’s just as well: with their insatiable curiosity and incessant questioning, children are born scientists! To help them understand the world around them, Little Guest offers you to combine theory and practice in a playful way, thanks to 5 easy and fun experiments to carry out at home.
Pressure, heat, refraction, gravity, electricity, natural phenomena call on the 5 senses and inevitably develop the children’s instinct of observation and logic. Well supervised and explained step by step, simple experiments with everyday objects and products offer unlimited learning possibilities.
From the age of 3 or 4, your child will be able to develop his manual coordination, his analytical mind, marvel at the physical and chemical reactions between the elements around him, and build with you the foundations of a scientific method, as a family… and while having fun.
1. The sympathetic ink
It is indeed very nice to think you are a secret agent, and to pass messages or little drawings incognito to a friend or a classmate, thanks to invisible ink!
When you put the paper near a source of heat, words appear as if by magic, revealing the mysterious contents of the missive.
But what chemical reaction hides behind this strange phenomenon?
For this experiment, you need:
- A lemon
- A sheet of white paper
- A brush
- A candle
- A lighter or a box of matches
- A container (e.g. a glass) and a clothespin
Squeeze the lemon (bottled lemon juice can also do the trick). Pour the collected juice into the glass container.
Soak the little brush with the lemon juice and put the desired drawings on the paper, or with the help of mum or dad, the words you intend to communicate.
Let the inscriptions dry on the paper for a few moments.
With a clothespin, hang the white sheet of paper.
Ask Mum or Dad to light the candle with the lighter and bring it closer to the hanging paper, but be careful not to ignite it!
As if by magic, the invisible inscriptions appear as the candle approaches, taking on a brown colour, thus delivering the content of your message.
Lemon juice or vinegar are colourless solutions that contain a lot of citric acid.
The drying and evaporation of the water contained in these liquids leaves the acid crystals on the surface of the paper.
Since the ignition temperature of these acidic compounds is lower than that of the paper, the heat quickly causes the words or drawings drawn on the sheet to appear.
2. The Rainbow
Who hasn’t marvelled at the magnificent gradation formed by the superimposition of the seven colours of a rainbow?
Nevertheless, if we know more or less that sun and humidity are involved in this natural phenomenon, what is it really?
For this experiment, you need:
- A basin filled with water
- A mirror
- A white sheet of paper
- A source of light (a flashlight for example)
Plunge the lower half of the mirror into the water basin, so that it forms an angle of more or less 45° with the bottom. This is half a right angle, but ask Mum or Dad to help you if you don’t know what it means.
Point the flashlight beam at the part of the mirror that is in the water.
Hold the white sheet of paper where the mirror reflects the light.
A pretty rainbow has formed on paper!
The rays of the sun, or those of the flashlight, are called white light. That is, it includes every natural colour, including red, orange, yellow, green, blue, indigo and purple.
But not all colours react in the same way when they move from an airy to a wet environment, which is why they separate to form a beautiful rainbow.
We use a rather complicated word for this: refraction.
3. The solar oven
Why don’t you go and cook yourself an egg? But not in any way: thanks to the sun!
As you probably know, sunlight is essential for life on Earth. Because it is a source of light that plants feed on through the phenomenon called “photosynthesis“, but also because it provides the heat necessary for the presence of liquid water on our planet.
But to cook an egg, you have to give this heat a boost.
For this experiment, you need:
- 1 egg
- 1 small glass jar
- 1 box of cereals
- 1 roll of aluminium foil
- 1 tube of glue
- 1 sheet of black drawing paper (or that you have painted black)
- 1 glass salad bowl
On a beautiful summer sunny day, break an egg in a small glass jar.
Cut out a box of cereal to get the longest piece possible.
Cover this surface with aluminium foil of the same length.
Place the jar containing the broken egg on the black foil in the sun and turn the bowl over.
Turn the aluminium-covered foil towards the sun, and place it behind the pot.
Bend it well and direct the sunlight through the bowl onto your egg.
After about 20 minutes, your egg is cooked!
Thanks to your aluminium-coated cardboard, you have in fact created a parabola, which thanks to its large surface area has amplified the thermal energy of the sunlight.
In addition, the black foil stored the heat of the rays, which raised the air temperature in the bowl, gradually causing the egg to cook.
It should be noted that in many countries, especially in Asia and Africa, the solar oven is commonly used. This is very practical, as solar energy is free and inexhaustible!
4. The magic mud
Many children have already played with a fun substance that is both resistant and flexible, or even viscous: the “slime“. Unfortunately, even though it is normally safe, it is often made with unnatural products, and often even chemicals.
Well, from now on you’ll be able to make it yourself, with edible ingredients from everyday life.
For this experiment, you need:
- 1 small bag of potatoes
- 1 food processor
- 2 large salad bowls (transparent, if possible)
- 1 large strainer
- 1 glass jar
- 1 bottle of tonic
- 1 small bowl
Cut 5 or 6 potatoes into very small pieces, using the food processor. Don’t hesitate to ask your mum or dad to help you.
Mix all this with a large amount of water in the bowl. After a few minutes the water will turn red.
Pour the contents of the bowl into the other bowl, straining the small pieces of potato through a strainer. You will then harvest your red water.
Wait a few minutes: you will notice that a white deposit has formed at the bottom of the bowl. That’s what we’re interested in, so you can remove the first water.
Then mix this white deposit with clear water again in your glass jar. A deposit of impurities will form on the surface of your white substance.
Again, quickly pour the contents of your jar into one of the bowls to keep only the white substance.
When it dries, it will turn into a powder after one or two days.
If you want to add a magical effect, pour a little bit of tonic over your powder in a small bowl.
The substance obtained is very resistant when you want to mix it, but it is possible to make a ball or sausage, a bit like a pizza dough.
On the other hand, as soon as you stop handling the dough, it suddenly becomes liquid and flows through your fingers!
To add to the mystery, turn off the light: your magic dough is fluorescent!
To make this magic paste, or magic “mud”, you have actually isolated what is called “starch” in the potato, and more commonly “starchy“. This molecule has amazing chemical and physical properties, because while it looks like a viscous liquid, it is also a fluid that stiffens under pressure.
That’s why your dough is hard when you want to handle it. It is also possible to use corn starch to achieve the same result.
Then, the tonic you have added contains quinine, which is a substance taken from a tree native to South America, and which fluoresces in the dark.
5. The tornado in the living room
You may already have seen an impressive climatic phenomenon: the tornado. It’s a huge whirlwind that forms in the atmosphere, in the clouds, and can do a lot of damage.
What if we created one in the living room?
For this experience, you need:
- Two 1.5 litre bottles
- Big sticky paper
Remove the corks from both bottles.
Fill one of the two bottles with water, but not completely: leave a little air at the bottom of the neck.
Place your bottle filled with water on a table, and turn the other empty bottle over the first one, making sure that the two necks touch each other.
That’s where Mum or Dad will probably be able to help you: using the big sticky paper, you have to glue the two bottles together. Don’t hesitate to make several turns, so that the whole thing is completely watertight.
To create the tornado, turn the full bottle over the empty one, and turn it over!
As it descends into the bottom bottle, the water forms a veritable whirlpool, resembling a real tornado.
A tornado is an atmospheric phenomenon, that is, it is formed by exchanges of cold and warm air.
But water, like air, is a fluid, and it reacts in more or less the same way.
In a real tornado, the cold air descends through the centre of the tornado, and the warm air spirals back up around this column of air, causing this enormous whirlwind.
You have easily recreated this phenomenon in your bottles by giving a circular dynamic to the water, which will allow it to spiral out through the neck of the bottle.
Jean-Philippe, 35 years old, musician and travel lover, from Brussels, Belgium