Safe Chemistry Experiments You Can Do at Home

You don’t need a laboratory to do real chemistry. With a few household materials and a notebook, you can run proper investigations: change one thing, keep everything else the same, observe carefully and explain what happened. The experiments below are chosen because they’re safe with sensible supervision, use everyday materials, and teach a genuine chemical idea. Several run over hours or days, which makes them good weekend projects.

For quick ten-minute demonstrations, see kitchen science: 10 experiments with household items.

Home safety rules first

• Ask an adult before starting, and have one nearby for anything involving heat or a knife.
• Only use the materials listed. Never mix household cleaning products. Bleach mixed with acids (including some toilet cleaners) or with ammonia gives off toxic gases.
• Don’t eat or drink anything used in an experiment, and use containers you won’t use for food again (or wash them thoroughly).
• Protect your eyes. Safety glasses are cheap; use them whenever liquids might splash.
• Label everything you leave standing, and keep it away from young children and pets.
• Wash your hands afterwards.

Why these rules matter is explained in lab safety rules.

1. Grow your own crystals

You need: table salt or Epsom salt (magnesium sulfate), hot water from the kettle (adult to pour), a clean jar, string, a pencil.

Method: Stir salt into hot water until no more dissolves (a saturated solution). Let undissolved salt settle, pour the clear solution into a clean jar, and hang a string from a pencil into it. Leave undisturbed for several days.

What’s happening: Hot water dissolves more solute than cold water. As the solution cools and water slowly evaporates, it becomes supersaturated, and the extra solute comes out of solution, building onto the regular arrangement of ions in a crystal. Slow cooling and evaporation give larger, better-shaped crystals.

Investigate: Does the cooling rate affect crystal size? Compare a jar in the fridge with one at room temperature.

2. What makes iron rust?

You need: four iron nails (not galvanised or stainless), four jars, tap water, cooking oil, salt, a desiccant sachet (from a shoebox or vitamin bottle).

Method:

• Jar A: nail in air only, with a desiccant sachet (dry air).
• Jar B: nail half-covered in tap water.
• Jar C: nail in water that has been boiled (to remove dissolved air) and cooled, with a layer of oil on top to stop air dissolving back in.
• Jar D: nail half-covered in salty water.

Check every day for a week.

What’s happening: Rusting needs both water and oxygen. Iron is oxidised to iron(III) oxide, hydrated. Salt speeds rusting up because the ions make the water a better electrical conductor, which speeds the electrochemical reactions. See oxidation and reduction.

Expected result: Most rust in D, some in B, little or none in A and C.

3. The rubbery egg

You need: a raw egg, white vinegar, a glass, a spoon.

Method: Put the egg in the glass and cover it with vinegar. Watch for bubbles. After 24 hours, carefully replace the vinegar with fresh vinegar. After 2–3 days, rinse the egg gently.

What’s happening: Eggshell is mostly calcium carbonate. Vinegar contains ethanoic (acetic) acid, which reacts with it:

CaCO₃ + 2CH₃COOH → Ca(CH₃COO)₂ + H₂O + CO₂

The bubbles are carbon dioxide. When the shell has gone, only the egg’s membrane holds it together, so it feels rubbery and translucent. See acids and bases in the home.

Investigate: Leave the shell-less egg in water, then in golden syrup. It swells in water and shrinks in syrup, because water moves through the membrane by osmosis.

4. Invisible ink

You need: lemon juice (or milk), a cotton bud, white paper, and an adult with a hairdryer or a warm (not hot) oven. Keep it away from open flames.

Method: Write a message with lemon juice. Let it dry completely until invisible. Warm the paper gently.

What’s happening: Lemon juice contains organic compounds, including sugars and acids, that char (oxidise and break down) at a lower temperature than paper. The message turns brown before the paper does.

Chemistry twist: Write a message with baking soda solution. Reveal it by painting over with red cabbage juice: the message turns a different colour because baking soda is alkaline. See red cabbage indicator.

5. Which markers contain which dyes?

You need: water-soluble felt-tip pens (black and brown work well), coffee filters or paper towel, a glass of water, a pencil and a clip.

Method: Cut a strip of filter paper. Draw a pencil line 2 cm from the bottom and put a dot of each ink on it. Hang the strip so the bottom dips in water but the dots stay above it. Wait until the water nearly reaches the top.

What’s happening: This is paper chromatography. Each dye in the ink has a different balance between dissolving in the moving water and sticking to the paper, so they travel different distances and separate. Black ink often turns out to be a mixture of blue, red, yellow and purple dyes.

Investigate: Measure how far each dye travels and calculate its Rf value.

6. A density tower

You need: honey, washing-up liquid, water (with food colouring), vegetable oil, and a tall clear glass. Optional: small objects such as a grape, a plastic bead and a cork.

Method: Pour each liquid slowly down the side of the glass, in that order, so they don’t mix. Then drop in small objects.

What’s happening: Each liquid has a different density (mass per unit volume). Denser liquids sink below less dense ones, and oil and water don’t mix because oil is nonpolar and water is polar. Objects float at the level where their density matches the liquid above and below. See density calculations and polar vs nonpolar molecules.

7. Yeast and hydrogen peroxide

You need (adult supervision): 3% hydrogen peroxide (from a pharmacy), a packet of dried yeast, warm water, washing-up liquid, a plastic bottle in a tray, safety glasses.

Method: Mix a spoon of yeast with a few spoons of warm water. In the bottle, mix about 100 cm³ of 3% hydrogen peroxide with a good squirt of washing-up liquid. Pour in the yeast mixture and step back.

What’s happening: Hydrogen peroxide slowly decomposes into water and oxygen: 2H₂O₂ → 2H₂O + O₂. Yeast contains an enzyme called catalase that speeds this up enormously. The oxygen is trapped by the soap as foam. The foam is warm because the reaction is exothermic. See reaction rates and catalysts.

Safety: Use only 3% peroxide, wear glasses, and don’t touch the foam until it’s cooled.

8. How much sugar is in a drink?

You need: a kitchen scale reading to 1 g, a measuring jug, sugar, water, and some drinks (a cola, a juice and a diet drink).

Method: Make standard solutions: dissolve 0, 25, 50, 75 and 100 g of sugar in water to make 1000 cm³ each (or scale down). Weigh exactly 100 cm³ of each and plot mass against sugar content. Then weigh 100 cm³ of each drink (let fizzy drinks go flat first) and read its sugar content from your graph.

What’s happening: Dissolved sugar makes a solution denser. This is a real analytical method: a calibration curve turns a measurement into a concentration. Compare your results with the labels. (Other dissolved substances contribute too, so the answer is approximate.)

Keep a proper record

Treat your kitchen like a lab: write the date, the method, what you changed, what you kept the same, your observations and your explanation. That’s how scientists work. See independent, dependent and control variables and how to write a lab report.

Key takeaways

• Real investigations are possible at home with safe materials and supervision.
• Never mix household cleaning products, and never eat or drink experiment materials.
• These experiments show solubility, rusting, acids and carbonates, charring, chromatography, density, catalysis and calibration.
• Change one variable at a time and record everything to turn an activity into an investigation.