Electrolysis of water facts for kids

A diagram showing how water is split into hydrogen and oxygen.

Electrolysis of water is a cool process that uses electricity to break down water. Water (H₂O) is split into two different gases: oxygen (O₂) and hydrogen (H₂). Think of it like taking apart a LEGO model with an electric tool!

This method can create useful oxygen for breathing or hydrogen, which can be used as a clean fuel. However, making hydrogen this way is usually more expensive than getting it from natural gas in big factories.

When electricity passes through water, a special chemical change happens. It's called a redox reaction. This means electrons are moved around. At one electric pole, called the cathode, a "reduction" happens. At the other pole, the anode, an "oxidation" happens. These reactions work together to split the water.

To make the process work better, sometimes a little bit of acid or a base is added to the water. This helps the electricity flow and the reactions happen more easily.

Here's the main idea of what happens:

• Water (H₂O) turns into hydrogen gas (H₂) and oxygen gas (O₂).

This is the overall reaction:

2 H₂O → 2 H₂ + O₂

It means two molecules of liquid water turn into two molecules of hydrogen gas and one molecule of oxygen gas.

How Electrolysis Works

Electrolysis needs a few key parts to work. You need a container for the water, two electrodes (which are like metal rods or plates), and a power source like a battery.

• Electrodes: These are the parts that touch the water and carry the electric current. One is the positive electrode (anode), and the other is the negative electrode (cathode).
• Electrolyte: This is the water, often with something added to help it conduct electricity. Pure water doesn't conduct electricity very well.
• Power Source: This provides the electricity to drive the reaction.

When the electricity flows, the water molecules break apart. Hydrogen gas bubbles form at the negative electrode, and oxygen gas bubbles form at the positive electrode. You can actually see these bubbles!

Uses of Water Electrolysis

Electrolysis of water has several important uses:

• Producing Hydrogen Fuel: Hydrogen is seen as a clean fuel because when it burns, it only produces water. Electrolysis is one way to make this fuel.
• Creating Oxygen: In some situations, like on spacecraft or submarines, electrolysis can be used to produce oxygen for people to breathe.
• Chemical Production: It's also used in some industrial processes to make other chemicals.

While it's a great way to get hydrogen and oxygen, the cost of electricity can make it more expensive than other ways of producing these gases. Scientists and engineers are always looking for ways to make electrolysis cheaper and more efficient.

Images for kids

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  A AA battery in a glass of salt water showing hydrogen produced at the negative terminal.

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  A device invented by Johann Wilhelm Ritter to study the electrolysis of water.

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  A diagram showing the overall chemical equation for water electrolysis.

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  A diagram showing how water, oxygen, and hydrogen behave under different conditions.

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  A Hoffman voltameter connected to a power supply for electrolysis.

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  A match test used to check for the presence of hydrogen gas.

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  This image shows what goes into and comes out of simple water electrolysis.

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  A chart showing the cost of hydrogen production at different natural gas prices.

See also

In Spanish: Electrólisis del agua para niños