Classic Back-to-School Experiments with APC Pure

As schools reopen, these classic experiments provide engaging demonstrations of key chemical principles. Each one uses well-known laboratory chemicals to illustrate concepts such as neutralisation, oxidation, and displacement.

Safety First: Always Use Gloves

When working with chemicals, protective gloves should always be worn. Even common reagents such as acids, bases and salts can irritate the skin, and some, like sodium hydroxide or copper sulphate, are hazardous on contact or when rubbed into the eye.

1. Baking Soda Volcano (Acid–Base Reaction)

The baking soda volcano became popular in the mid-20th century as a classroom demonstration. Its simplicity and dramatic foaming reaction still make it a favourite for introducing chemical change.

Materials:

• Sodium Hydrogen Carbonate

• Citric Acid or Acetic Acid (3%)

• Optional: food colouring, dish soap

• Container or plastic bottle

Steps:

1. Place 2 tablespoons of Sodium Hydrogen Carbonate into the container.

2. Mix the acid with food colouring and a little dish soap.

3. Pour the mixture into the Sodium Hydrogen Carbonate and watch the eruption of foam and gas.

2. Elephant’s Toothpaste (Catalytic Decomposition)

This foamy reaction demonstrates how catalysts speed up chemical change. Hydrogen peroxide breaks down into water and oxygen, but with a catalyst the process becomes vigorous and spectacular.

Materials:

• Hydrogen Peroxide (3% for home use, stronger in labs)

• Potassium Iodide solution (or yeast suspension)

• Dish soap

• Food colouring (optional)

Steps:

1. Mix hydrogen peroxide with a squirt of dish soap in a container.

2. Add food colouring for effect.

3. Quickly add the catalyst and observe towers of warm foam.

3. Blue Bottle Reaction (Redox Chemistry)

A “magic” solution that changes colour on shaking, then fades again when left still. It’s an effective way to show oxidation and reduction in action.

Materials:

• Glucose (dextrose)

• Sodium Hydroxide solution

• Methylene Blue solution

• A clear bottle with stopper

Steps:

1. Dissolve glucose and sodium hydroxide in water in the bottle.

2. Add a few drops of methylene blue.

3. Shake the bottle to turn the liquid blue, then leave it to fade to colourless. Repeat the cycle.

4. Copper and Iron 

This experiment shows the reactivity series in action. An iron nail placed in copper sulphate solution becomes coated with copper metal.

Materials:

• Copper Sulphate solution

• Clean iron nail or strip

• Beaker

Steps:

1. Fill a beaker with blue copper sulphate solution.

2. Submerge the iron nail.

3. Observe as copper slowly deposits on the nail and the solution turns pale green.

5. Indicators in Action (pH Testing)

Indicators are simple yet powerful tools for understanding acids and bases. Litmus and phenolphthalein remain staples in school laboratories.

Materials:

• Red and blue litmus paper

• Phenolphthalein solution

• Dilute hydrochloric acid

• Dilute sodium hydroxide

Steps:

1. Test the acid and base solutions with litmus paper and note the colour changes.

2. Add phenolphthalein to the sodium hydroxide – it will turn pink.

3. Add acid drop by drop until the solution becomes colourless again.

Conclusion 

These classic experiments are a great way to start the school year, combining clear science with engaging demonstrations. 

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