Michael Faraday was one of the most important experimental physicists who ever lived. His work in understanding and using electricity has allowed many of our technological advances in the last two centuries.

Make your own hydrogen!

Download a pdf of the instructions here.

What you need...

A battery: 1.5V C cell is large enough
Two pieces of thin wire; even metal food ties will do.
A glass of water.
Two teaspoons of sodium bicarbonate.

How long will it take?

It takes about 15 minutes to put the experiment together, and once working the hydrogen is produced immediately.

What to do...

1.  Have a look at the instructions in the students' section.

2.  Although this experiment is relatively safe, students should be careful not to drop the battery in the water (taping the wires to each end of the battery is preferable than them holding it).  Also substituting the sodium bicarbonate for salt will work, but carries the risk of producing a small about of chlorine at the anode (positive wire).  It shouldn't be necessary to use a higher voltage battery, but if you do want to substitute a larger one -

and make more gas - take precautions by using insulated wire and proper electrical clips to connect the circuit.

Curriculum Links

Splitting water
Science

Working scientifically

Experimental skills and investigations

  • use appropriate techniques, apparatus, and materials during fieldwork and laboratory work, paying attention to health and safety

Scottish Curriculum Links:

Science

SCN 3-04a

Planet Earth - Energy sources and sustainability

I can use my knowledge of the different ways in which heat is transferred between hot and cold objects and the thermal conductivity of materials to improve energy efficiency in buildings or other systems.

SCN 3-04b

Planet Earth - Energy sources and sustainability

By investigating renewable energy sources and taking part in practical activities to harness them, I can discuss their benefits and potential problems.

SCN 4-04a

Planet Earth - Energy sources and sustainability

By contributing to an investigation on different ways of meeting society's energy needs, I can express an informed view on the risks and benefits of different energy sources, including those produced from plants.

SCN 3-15b

Materials - Properties and uses of substances

SCN 3-19b

Materials - Chemical changes

Technologies

TCH 3-01a

Technological developments in society

From my studies of technologies in the world around me, I can begin to understand the relationship between key scientific principles and technological developments

TCH 4-01a

Technological developments in society

I can compare traditional with contemporary production methods to assess their contribution in the world around me and explain the impact of related technological changes.

 

Splitting water

coal power stationWe know today that electricity is the flow of electrons around a wire.  These electrons are driven by a 'potential difference', a willingness to get from the negative side of a battery to the positive.  It is hard to imagine that some of the most important work on electricity was done nearly 100 years before the electron was discovered!

Electricity has changed how we live.  We have houses full of useful - and fun - electrical gadgets, lights which allow us to do what we want even if it is completely dark outside, and electricity is much safer than the open flames of 200 years ago.

However, we still rely on fossil fuels - coal, oil and gas - for a large part of our electricity generation, and for other important things, such as to power our vehicles.  But fossil fuels are limited and when they burn they give out carbon dioxide which is leading to climate change.

Are there any better alternatives to this?  Hydrogen may be the answer...  Hydrogen fuel cells combine hydrogen and oxygen to create water, and convert the energy that is produced into electricity.

hydrogen busHydrogen can be produced directly from fossil fuels, but carbon dioxide is released when we do this.  It is much better to produce it without burning fossil fuels.  Electricity generated by wind or solar power can be used to break water apart and the hydrogen can be used later to make electricity again.  This is one way that energy from wind and solar power can be stored and used when it isn't windy or sunny.  The hydrogen fuel cells can be used to create electricity in our homes or maybe even in electric cars in the future!  Some London buses are powered by hydrogen fuel cells.

Michael Faraday worked on electrolysis: combining chemistry and electricity.  In  electrolysis you can use electricity to break different substances apart - in this case water to get hydrogen.  You can then store the hydrogen to use later!

Key fact: When you use electricity to split water, one of the products is hydrogen, which can be stored as a fuel. Hydrogen can then be used to make electricity again.

 


Make your own hydrogen!

Download a pdf of the instructions here.

What you need...

A battery: 1.5V C cell is large enough
Two pieces of thin wire; even metal food ties will do.
A glass of water.
Two teaspoons of sodium bicarbonate.

What to do...

hydrogen diagram_2501.  Add the sodium bicarbonate to the water and stir it until it has dissolved.

2.  Attach a wire to each side of the battery.  You can use sticky tape or even just hold them in place with your fingers.

3.  Put the other ends of the wires in the water.  Don't let the wires touch each other and don't drop the battery in the water!

4.  If you look carefully you will see bubbles comings off the wire that is attached to the negative side of the battery.  You may even see a few bubbles on the wire connected to the positive side too.

What is happening?

Electricity always needs a complete circuit to make the current flow. For a lamp to light in a circuit the electricity flows from a battery through a wire to the lamp and then through another wire back to the battery.

This is a circuit too. Electrons flow around the wire, when the wire meets the water  ions flow through the water. Faraday was first to use the word ion. Ions are what are left over when atoms lose or gain an electron. If an atom gains an electron it becomes negatively charged and moves towards the positive side of the battery.  If an atom loses an electron it becomes positively charge and moves towards the negative side of the battery.

When a substance like sodium carbonate dissolves in water it breaks up to form ions. Sodium ions are positively charged and the bicarbonate ions are negatively charged. These ions formed from the splitting of the sodium bicarbonate molecules are what carry the electricity through the water, and so the circuit is complete.

In water some of the water molecules break up giving hydrogen ions - this is a bit like the water dissolving in the water!  At the cathode - the wire connected to the negative side of the battery these hydrogen ions bind together to make hydrogen gas, which bubbles off.  At the positive wire oxygen should form in smaller amounts.