Blog Post Tuesday 03 January 2017
Wondering how to amuse your kids during the school holidays? How about setting them up with a few science projects where they’ll get to learn more about the wonders of electricity? Here are three ideas which will help your children learn more about electrical energy - and have fun while doing it.
Static electricity is all around us. You’ve probably already felt it when you’ve touched someone’s hand and experienced a sharp jolt or shock. To teach your kids more about static electricity, you’ll need two inflated balloons, each on a piece of string, as well as an aluminium can and a piece of woollen fabric.
Start by rubbing the balloons against the fabric. Then, holding each balloon by its string, try to move them together. Observe what happens. Do they move towards each other or away from each other?
Next, rub one of the balloons backwards and forwards on your child’s hair, then slowly pull it away. Have them look into a mirror as you do this and watch what happens.
Now, take your aluminium can and put in on its side on top of a table. Rub the balloon against your child’s hair again and then put it near the can. You’ll see the can move towards the balloon. If you move the balloon away, the can will follow it.
The rubbing action of the balloons against hair or fabric has created static electricity. As you rubbed the balloons, they took some of the electrons (which are negatively charged particles) from the hair or the fabric so that the balloons became negatively charged. Taking these electrons meant that the hair and the fabric became positively charged as they now had more protons than electrons. As positive and negative attract, positively charged hair moved towards the balloon, as did the can. However, as both balloons are negatively charged, they moved away from each other as there is no attraction.
We all know what happens when a battery runs out, but why do they run out? And more to the point, how do batteries work? Our easy lemon battery project will teach you all you need to know.
All you need is a lemon or other piece of citrus fruit, some 18-gauge copper wire, a wire stripper and a steel paper clip. Start with a piece of copper wire about 2.5 inches in length. Strip the plastic insulation away, and then straighten your paper clip and cut to the same length as your wire. Sandpaper the ends of the wire and the clip until they’re smooth.
Loosen the juice in the lemon by rolling it gently on a table, and then stick about one inch of the copper wire into the lemon. Moisten your tongue with spit and then put your tongue on the copper wire. What do you feel?
Stick the paperclip into the lemon close to the copper wire, but making sure that they don’t touch. They need to be close to each other to take part in the chemical reaction that’s about to happen. Now, touch your tongue to both wires at the same time. Did you feel a tingling sensation? Or notice a slightly metallic taste?
If you felt a tingle or tasted metal, it shows that your lemon had made an electric current. This happens when tiny electrons move across your tongue. Electrons are negatively charged particles that move around the centre of an atom.
The battery you made is a voltaic battery, which means it has two different types of metals acting as electrodes. Electrodes are the point where the electrons enter and leave a battery. In order to work, the electrodes must be placed into a substance called an electrolyte. The citric acid in the lemon acts as an electrolyte in the fruit, while the salt in your saliva worked in the same way for your tongue.
In order to power a light bulb, you need a circuit for the electricity to flow through. A circuit can be made with copper wire, a 6-volt battery, some alligator clips and a light bulb. (Click here for a Click here for a step-by-step guide on how to do this.) Alternatively, you can buy ready-made circuits to make the job easier, some of which contain switches, buzzers and electric motors. If you don’t have a switch in your set, make your own using an index card, two metal paper fasteners and a paper clip. By touching the paper clip to both of the paper fasteners, your bulb will light up. Move the paper clip away and you’ll break the circuit, so the light will go out.
You can also try using different voltages of battery to see how it affects the brightness of your light bulb. Or how about experimenting with different materials to see how they affect the circuit? Try items such as coins, metal bottle caps, a piece of sponge, or an eraser. Put them in front of the paper fastener on your switch and watch what happens.
If these experiments have sparked your child’s imagination, why not try taking their knowledge a little further? There are plenty of fun science experiments to fill up the school holidays.