Chemistry
Chemistry projects for class 1 to 5: 24 ideas.
Each project below opens to its own page with what it shows, the science behind it, the materials, safety, step-by-step instructions, what you should see and viva questions. Many can be made from things at home; where a kit helps, the page links one.
Other subjects for class 1 to 5: Physics, Biology, Maths, Earth and space, Electronics and robotics, Environment, Computing and coding.
Rainbow in a glass (density tower)
Water with more sugar dissolved in it is denser, so it sinks below water with less sugar. Layers of differently sweetened, coloured water stack up like a rainbow.
Erupting volcano model
Vinegar (an acid) reacts with baking soda (a base) and gives off carbon dioxide gas, which pushes the foam out. Real volcanoes erupt molten rock, so the model shows the shape of a volcano, not its cause.
Turmeric paper strips that spot soaps and acids
Turmeric contains a yellow dye called curcumin that turns reddish brown in a base such as soap water and stays yellow in an acid such as lemon juice. Home-made turmeric strips work like litmus paper and let you sort kitchen liquids into acids, bases and neutrals.
Growing sugar crystals on a string, like mishri
Hot water dissolves far more sugar than cold water. As a very strong sugar solution cools and slowly loses water, the extra sugar comes out of solution as crystals that grow on a string, which is exactly how mishri is made.
Crystal shapes of salt, sugar and alum under a magnifier
Each substance makes crystals of its own fixed shape: salt forms cubes, sugar forms slanted blocks, and alum forms pointed double pyramids. Looking at grains with a magnifier shows that crystals are not random lumps but neat, repeating shapes.
Stirring or warm water: which dissolves sugar faster?
Dissolving gets faster when the water is warmer, when the liquid is stirred, and when the sugar is in smaller pieces. A fair test with a stopwatch shows which of these three has the biggest effect.
Making salt from salty water in a sunny tray
When salt water is left in the sun, only the water escapes as vapour and the salt stays behind as white crystals. This is how salt pans on the coast of Gujarat and Tamil Nadu produce the salt we eat.
Measuring the gas from baking soda and vinegar with a balloon
Baking soda and vinegar react to make carbon dioxide gas, which inflates a balloon fitted over the bottle. Using more baking soda makes a bigger balloon, until the vinegar is used up and extra baking soda does nothing.
Baking soda invisible ink revealed without any heat
A message written in baking soda water dries invisible, but a wash of turmeric water or purple grape juice turns the writing a different colour because baking soda is a base and these juices are indicators. No heat or flame is needed.
Chromatography of the colours in candy coatings
The coloured coating on candies such as Gems is often a mixture of several food dyes. Water climbing up filter paper carries the dyes at different speeds, so a single dot of colour spreads into separate bands and shows what the mixture contains.
Ice melting race: salt, sugar, sand or nothing?
Sprinkling salt on ice makes it melt faster than plain ice, sugar helps a little, and sand hardly at all. Dissolved substances lower the temperature at which water freezes, so salted ice melts even when the room is cold.
Three states of water in a bag taped to a sunny window
A zip bag with a little water and an ice cube, taped to a sunny window, shows all three states of water: the ice melts, the water evaporates, and the vapour condenses into drops on the cool upper part of the bag that run back down like rain.
Lava bottle with oil, water and a fizzing tablet
Oil floats on water because it is less dense, and the two do not mix. A piece of fizzing antacid tablet (ENO or similar) dropped in makes carbon dioxide bubbles that lift blobs of coloured water up through the oil and let them fall again, like a lava lamp.
Floating egg: how many spoons of salt does it take?
A fresh egg sinks in plain water but floats once enough salt is dissolved, because dissolving salt makes the water denser than the egg. Counting the spoons needed turns a trick into a measurement of density.
Naked bouncy egg: vinegar dissolves the shell
An eggshell is calcium carbonate, which reacts with the acid in vinegar and fizzes away as carbon dioxide, leaving the egg held only by its soft membrane. The rubbery egg also swells, showing that water passes into it through the membrane.
Frost on a tin can using only ice and salt
Crushed ice mixed with salt gets colder than ice alone, below the freezing point of water. The outside of a tin filled with the mix becomes so cold that water vapour from the air freezes on it as a white frost, which never happens with plain ice.
Does dissolved sugar still weigh the same?
When sugar disappears into water, its mass does not disappear: the sugar water weighs exactly as much as the sugar and the water did separately. Weighing before and after shows that dissolving spreads the sugar out but destroys nothing.
Why apple slices turn brown and what stops it
A cut apple turns brown when enzymes in it react with oxygen in the air. Lemon juice, salt water, sugar water and cold slow or stop the change, which shows how cooks keep fruit looking fresh.
Candy colour race: hidden dyes in coated sweets
Coloured sweets often use a mix of dyes, and water carrying them up paper moves different dyes at different speeds. You split the colours of several sweets and learn how to separate a mixture without any chemicals.
Which fabric soaks up the most water: cotton, nylon, wool or polyester?
Cotton and wool fibres absorb a lot of water, while nylon and polyester absorb little. By weighing identical fabric squares before and after soaking, you find which fabric is best for towels and which for raincoats.
Walking rainbow: colours that climb a paper towel
Water climbs up paper and carries colours with it. When red and yellow meet in the middle they make orange, and blue and yellow make green.
Water drops on a coin: how many drops fit?
Water drops hold together like a skin and make a dome. A coin can hold many drops before the water spills over.
What dissolves in water? A kitchen tray test
Some things disappear in water, such as salt and sugar, and some do not, such as sand and flour. We call the first group soluble.
Soap bubble wands: do square wands make square bubbles?
Bubbles are always round, whatever the shape of the wand. Soap film pulls itself into the shape with the least surface, which is a sphere.