STEM Experiments

The reaction is summarised by this formula:

2 H2O2 →  2 H2O + O2 

Hydrogen peroxide (H2O2) naturally breaks down into water and oxygen.  It is stored in opaque containers to help slow down this process. The yeast speed up the reaction. Dish soap catches the oxygen and makes bigger bubbles and the food colouring makes it look cool.  The foam and bottle feel warm because the reaction is exothermic - it releases energy as heat.

Read more about this cool experiment here.

Materials needed:

• A clean bottle

• 6% hydrogen peroxide

• 1 tablespoon (or one packet) of dry yeast

• At least 3 Tablespoons (or 15 ml) of warm water

• Liquid dishwashing soap

• Food coloring

• Small cup

• Funnel

The reaction is summarised by this formula:

CH₃COOH + NaHCO₃ → CO2 + H2O + Na+ + CH3COO-

The acid (vinegar, otherwise referred to as acetic acid) reacts with the carbonate (baking soda, also known as sodium hydrogen carbonate) in an acid-carbonate reaction to produce carbon dioxide, which inflates the balloon!

Find out more about what you need to do here!

Materials needed:

• Plastic bottle

• Vinegar

• Baking soda

• Balloon

• Funnel

• Spoon

This robotic hand replicates the tendons in our arms and helps show what mechanisms allow our body parts to move.

You can find a video to learn to build it yourself here!

Materials needed:

• Cardboard

• Glue (Hot glue is recommended)

• Straws

• String

• Velcro strips

The food colouring solution has the highest density amongst the shaving cream, and water causing it to sink to the bottom.

[Low to high density: shaving cream → water → food colouring]

Learn more about how to do this experiment here :)

Materials needed:

• A couple of clear glasses, vases, or bowls

• Food colouring

• Shaving cream

• Small bowls or containers

• Water

• An eye dropper, syringe or 1/4 teaspoon measuring spoon

When vinegar (otherwise called acetic acid) is added to the egg, it breaks down the eggshell (which contains calcium carbonate) to form carbon dioxide, a solution and water. As a result, the only thing holding the egg together is the membrane of the egg (the thin layer of skin), which does not break easily. Hence a bouncy egg is formed!

Read more about how to make your own here.

Materials needed:

• Raw egg

• Glass or jar

• Vinegar

Do you wonder how food gives us energy to move? It contains chemical potential energy that can be converted into other forms of energy. In this case, the chemical potential energy in the potato is converted into electrical energy (or simply electricity). This is used to power the circuit and make the light bulb light up!

Want to find out more about this? Click here!

Materials needed:

• Potatoes

• Knife

• Copper and silver coins (or copper and zinc strips)

• 3 wires with crocodile clips attached

• Small LEDs or lightbulbs

Alternatively, if you do not have potatoes, this experiment also works with lemons, apples and even grapefruits! You can research more into this here.