Education
Promoting science at school
Experiments
Electricity in history
No one invented electricity. It has always been there. In ancient China, sailors used natural magnets called lodestones which were dug from the ground to make the first crude compasses. Lodestones are pieces of rock with a vein of magnetised metal running through them.
In ancient Greece, a type of yellow rock called amber was used to make small ornaments. At that time, silk was a popular cloth worn by the rich. They found that rubbing silk against amber ornaments would attract pieces of straw and dust.
Rubbing materials together can sometimes cause parts of atoms called electrons to move. Electricity is the movement of electrons.
Our experiments
You can conduct your own scientific experiments to learn about electricity using everyday objects you'll find in your home. Just click on the links below and off you go!
Experiment A: Lemon battery
What you will need:
- Copper and zinc metal sheets
- A lemon
Instructions
- Cut a piece of copper and zinc metal to the size shown and point the ends.
- Gently squeeze the lemon to release the juice - (don't burst it though!) and cut two slots in the lemon's skin 20mm apart.
- Push the copper and zinc plates into the lemon cuts.
Result:
The bitter taste of lemon is caused by the citric acid that it contains.
The acid produces electricity by chemical action on the metal plates. You can test it for electricity using your electricity detector.
Experiment B: Make the Electricity Detector
What you will need:
- An empty matchbox (or a strip of cardboard folded six times)
- A spool of fine wire
- Blu-tac or adhesive
- A pocket compass
- Some sticky tape
- A small wood block
- Two small thumb tacks
Instructions
- Neatly wind the fine wire around the empty matchbox or heavy cardboard within 5mm of each end. When the coil is wound secure the wire ends with tape.
- Secure the coil to the wood block. Strip the insulation from the wire ends and connect to the small thumb tacks.
- Stick a small piece of Blu-Tac to the back of the pocket compass.
- Secure the compass on top of the wire coil.
Result:
When electricity flows through the coil it creates a magnetic field. This field will cause the compass needle to move. You can use your Electricity Detector to check if electricity is flowing.
Experiment C: Get Charged
What you will need:
- A plastic comb
- Dry hair (the longer the better!)
- Small pieces of paper
- A tap
Instructions
- Take the plastic comb and run it through your dry hair lots and lots of times.
- Sprinkle the small pieces of paper on a table or counter.
- Stick a small piece of Blu-Tac to the back of the pocket compass.
- Now take the comb and bring it close to the small, light pieces of paper. Do not touch the paper with the comb.
Result:
The small light pieces of paper are attracted to the comb.
Why does this happen?
Electrons have a negative (-) charge. When you run the comb through your dry hair again and again, electrons are collected on its surface. This gives the comb a negative charge. When you bring the negatively charged comb close to the small pieces of paper the electrons on the paper are repelled to the opposite side of the paper. This leaves the small pieces of paper positively (+) charged. Since opposite charges attract, positive and negative, the paper (+) is attracted to the comb (-).
Remember, a larger negative charge is built up on the comb if you run the comb through your hair more times. You need a strong negative charge to get the small pieces of paper to move.