Safe Chemistry Experiments for Home Learning

Chemistry is often called the "central science" because it connects physics and mathematics with biology and environmental science. For children, chemistry experiments offer immediate visual feedback—colour changes, fizzing reactions, and surprising transformations that seem almost magical. The experiments in this guide use common household ingredients and are safe when conducted properly, making them perfect for home learning.

Before You Begin: Safety Essentials

Even with safe household chemicals, good laboratory practices matter. Establishing these habits now prepares children for more advanced chemistry later.

• Eye protection: Safety goggles should be worn for all experiments involving liquids
• Protective clothing: Old clothes or a lab apron protect against stains
• Work surface protection: Newspaper or plastic sheets make cleanup easier
• Ventilation: Work near an open window or in a well-ventilated area
• No tasting: Never taste or eat anything used in experiments
• Hand washing: Wash hands thoroughly after every experiment

Understanding Chemical Reactions

Before diving into experiments, help children understand what a chemical reaction actually is. In a chemical reaction, substances combine to form new substances with different properties. The starting materials are called reactants, and the new substances are called products. Signs of chemical reactions include colour changes, gas production (bubbles), temperature changes, and the formation of precipitates (solids from liquids).

Beginner Experiments (Ages 6-8)

Classic Volcano: Acid-Base Reaction

This timeless experiment demonstrates an acid-base reaction that produces carbon dioxide gas. Place a small container (representing the volcano) in a tray to catch overflow. Add two tablespoons of bicarbonate of soda to the container. Mix a few drops of food colouring with half a cup of vinegar, then pour into the container and watch the eruption.

The science: Vinegar (acetic acid) reacts with bicarbonate of soda (sodium bicarbonate) to produce carbon dioxide gas, water, and sodium acetate. The rapid gas production creates the bubbling "eruption."

Extend the learning: Test different amounts of each ingredient. What happens with more vinegar? More bicarbonate of soda? Can you make the reaction slower or faster?

Invisible Ink: Oxidation

Squeeze lemon juice into a small bowl. Use a cotton bud to write a message on white paper using the juice as ink. Let the paper dry completely—the message will become invisible. To reveal the message, have an adult carefully hold the paper near a warm light bulb or use a hair dryer on the warm setting.

The science: Lemon juice contains carbon compounds that are colourless when diluted. When heated, these compounds oxidise and turn brown, revealing the message.

Dancing Sultanas: Gas Behaviour

Fill a clear glass with carbonated water. Drop several sultanas into the water and watch them sink, rise, sink, and rise again in a "dance."

The science: Sultanas are denser than water, so they sink. But carbon dioxide bubbles attach to their rough surface, making them buoyant enough to float. At the surface, bubbles pop and release, so the sultanas sink again.

Intermediate Experiments (Ages 9-11)

Elephant Toothpaste: Catalysed Decomposition

This dramatic experiment creates a foam "explosion" that looks like toothpaste for an elephant. In a bottle, mix half a cup of 6% hydrogen peroxide (available from pharmacies), a squirt of dish soap, and food colouring. In a separate container, mix one tablespoon of dry yeast with three tablespoons of warm water. Pour the yeast mixture into the bottle and step back.

The science: Hydrogen peroxide naturally decomposes into water and oxygen, but very slowly. Yeast contains an enzyme called catalase that speeds up this reaction dramatically. The dish soap captures the released oxygen as foam.

Safety note: Use only 6% hydrogen peroxide for home experiments. Higher concentrations require laboratory safety equipment.

Chromatography: Separating Mixtures

This beautiful experiment reveals the hidden colours in black markers. Cut coffee filters into strips. Draw a thick line of black water-soluble marker about 2cm from the bottom of each strip. Place the bottom of the strip in a shallow dish of water, keeping the marker line above the water level. Watch as water travels up the filter, separating the ink into its component colours.

The science: Black ink is often a mixture of several coloured dyes. Different dyes travel at different speeds through the filter paper, separating them visibly. This technique is used in laboratories to analyse complex mixtures.

Extend the learning: Test different brands of markers. Do they contain the same colours? Try coloured markers too—what hidden colours do they contain?

Density Rainbow

Create a layered rainbow of liquids that do not mix. In a tall clear glass, carefully layer the following liquids in order (pouring slowly over the back of a spoon): honey, corn syrup, dish soap, water (with food colouring), vegetable oil, rubbing alcohol (with different food colouring). Each liquid has a different density, so they stack on top of each other.

The science: Density determines whether substances float or sink. Liquids arrange themselves from densest at the bottom to least dense at the top.

Advanced Experiments (Ages 12+)

pH Indicator from Red Cabbage

Create a natural pH indicator by boiling chopped red cabbage in water for 15 minutes, then straining the liquid. This purple solution changes colour based on acidity: red in acids, purple in neutral solutions, green in weak bases, and yellow in strong bases. Test various household substances—lemon juice, baking soda solution, soap, vinegar—and record the colour changes.

The science: Red cabbage contains anthocyanins, pigments that change colour depending on the pH of their environment. This is how scientists and gardeners test soil and solution acidity.

Extend the learning: Create a pH scale chart showing which substances are acids, neutral, or bases. Research why pH matters in contexts like swimming pools, gardening, or cooking.

Crystal Growing

Grow your own crystals from supersaturated solutions. Dissolve as much alum, Epsom salt, or sugar as possible in hot water, stirring until no more dissolves. Pour into a clean jar and suspend a string or pipe cleaner in the solution. Over several days, crystals will form as the water evaporates.

The science: When water evaporates from a supersaturated solution, the dissolved substance comes out of solution in a regular crystalline pattern. Different substances form different crystal shapes based on their molecular structure.

Troubleshooting Common Problems

Reaction Not Working

Check that ingredients are fresh—old bicarbonate of soda or flat vinegar will not react well. Ensure measurements are accurate. Some reactions require specific temperatures, so check if your materials are too cold.

Unexpected Results

Unexpected results are not failures—they are opportunities for investigation. Ask: What was different from the expected outcome? What might have caused this? Can we test our hypothesis about why?

Cleanup Challenges

Most household chemistry experiments clean up with water and dish soap. For stubborn residues, a paste of bicarbonate of soda and water is mildly abrasive. Always dispose of materials safely—most can go down the sink with plenty of water.

Building Chemistry Understanding

Isolated experiments are fun, but connected learning builds understanding. Help children see patterns: many experiments involve acids and bases; gas production is a common sign of reactions; dissolving and mixing are different processes. These connections prepare them for formal chemistry education.

Above all, maintain a sense of wonder. Chemistry explains the transformations we see in cooking, cleaning, and nature. When children understand that chemistry is everywhere, they begin to see the world through a scientific lens.