“How, where or when we’re magnets found or made?” asks Sam (11)

Thanks for the question Sam. Magnets and magnetism was first discovered about  9000 years ago. A long time ago. It was found in rocks and called ‘lodestone’. Lodestone is a naturally occurring compound of iron. It is thought that it was magnetised by lightning strikes.

We will make our own magnets by using a slightly weaker form of electricity.  Here are my team.

Firstly let us try to make a magnet (without using lightning)

You will need a battery and a length of wire and some paperclips. The a collection of nails. Try and find as many different nails as you can. Wrap the wire around the nail and sellotape the bare wire ends to the terminals of the battery. See the diagram below. See how many paperclips you can pick up? Are some nails better than others?

DO NOT USE MAINS ELECTRICITY. IT IS VERY DANGEROUS. 

You might have found out that only certain metals can be made into magnets. These metals are called ferromagnetic metals.

Included in this group are the metal iron and the alloys of iron with the metals cobalt, nickel.

It is thought that in these metals (including iron) have some electrons called ‘free electrons’ (not sure what an electron is, then go to Science Master Special – Atoms and Atomic Structure). It is these ‘free electrons’ that are involved in magnetism. In the alloys the  ‘free’ electrons align themselves with the magnetism of the external magnet, making a (for the alloys) a permanent magnet.

Look at the short video I have made below. In the ferromagnetic metal (iron alloy) crystal domains you will see free electrons. In the metal these will be moving freely. As they begin to interact with the external magnetic field, they begin to align themselves, making a permanent magnet.

“How does a magnet become a magnet?” asks Ava (11)

A brilliant question Ava. I asked my team for their thoughts.

Yes team you are quite right there are some limitations to magnet making. The main one is that only certain metals can be made into magnets. These metals are called ferromagnetic metals.

Included in this group are the metal iron and the alloys of iron with the metals cobalt, nickel and some other rare earth elements .

It is thought that in these metals (including iron) have some electrons called ‘free electrons’ (not sure what an electron is, then go to Science Master Special – Atoms and Atomic Structure). It is these ‘free electrons’ that are involved in magnetism. In the alloys the  ‘free’ electrons align themselves with the magnetism of the external magnet, making a (for the alloys) a permanent magnet. For iron alone the magnetism is only temporary and you can test this in the experiment below.

 

Look at the short video I have made below. In the ferromagnetic metal (iron alloy) crystal domains you will see free electrons. In the metal these will be moving freely. As they begin to interact with the external magnetic field, they begin to align themselves, making a permanent magnet.

 

 

 

 

 

 

 

 

 

 

 

Questions on electricity were asked by Gavin (10), Tegan (10) and Hayden (9)

Gavin asked “Why does the energy flow through the wires?”

Tegan asked “How does electricity work?”

Hayden asked “How do batteries springs and wires make a complete circuit?”

So how does this compare with a modern day battery. lets have a look and think about Gavins question.

Hayden and Tegan. In the circuit below the  energy flows around the circuit when the switch is closed. Why? What are wires made of? What is special? If the wires were plastic do you think electricity would be able to pass through it? Try and make your own circuits with different materials.

Electricity is linked to the passage of negatively charged electrons. These were very comfortable in the battery until it was connected to a circuit (a circuit is a continuous pathway) and the switch was closed. The circuit gave the electrons (negatively charged) a passage to the positively charged end of the battery. Electricity (electrons) flowed and accompanying the electrons was energy. Look at the Science Master Special on Energy and why not try the Circuit Quiz.

 

Do not play with mains electricity. It is very dangerous and could kill you.

“Why does every country have different plug sockets?” asks Harry (10)

Thanks team. The third socket, the Earth socket is sometimes called the ‘grounding socket”. Lets try to make our own circuit to find out a little bit about this.

You would need a battery, some wire, a light bulb in a bulb holder and let’s say a cup with some damp sand in it.

 

Push the earth wire into the wet sand and see what happens.

The Earth socket on a UK plug is designed for problems where the electricity that you are using becomes unsafe, for example a wire inside a washing machine touches the case that the machine is contained in. The case it attached to rubber, non conducting wheels. You touch the case, with your leather soled shoes and you then get an electrical shock. If the case is attached to the earth wire the electricity finds an easy route to escape and this causes safety switches to open in the fuse box of the circuit. In the old days it would make a fuse melt and thus break the circuit.

The Earth socket is therefore a safety socket. Lots of appliances nowadays are so well insulated (protected) that an Earth protection is unnecessary. Some plugs have a plastic third pin. Two pin plugs have never had this additional protection.

Another experiment that you might like to try is changing the wet sand for other materials. Try leather, metals, china, dry sand, cloth ….. all sorts of materials. What an experiment! Brilliant.

DO NOT EXPERIMENT WITH MAINS ELECTRICITY

(updated 18/5/2017)

Liam (10) asks “Why does electricity go around a circuit?”

 

Thanks for that team , a very informative introduction. It’s usually the furthest electron that is involved in moving the electrical energy around the circuit.

I have tried to create a small animation to show how this might happen. The ‘pipes’ are the copper metal wire. the dots are the outermost electron attached to the numerous copper atoms. The battery is the ‘motor’ that makes the electrons move. To find out a bit more about how the battery work have a quick look at Sadies question.

Electrons are negatively charged particles so the negative terminal of the battery is ‘pushing’ the electrons while the positive terminal of the battery  is ‘pulling’ the electrons SO when the switch is closed all the electrons in the circuit start moving together.

Who do you think discovered that opposite charges attract and negative charges repel?

Now what about the filament in the bulb. Any idea why that starts producing light? Any thoughts on both these questions, let me know in the ‘Leave a Reply ‘ box.

 

 

Sadie (8) asked “How do batteries work?”

Sadie, many thanks for your question. I asked my friends to help me…

 

Yes I remember doing that, it wasn’t easy but I did get the led to light up.

Let’s start with a possible definition of a battery – It’s a device that converts chemical energy into electrical energy. If you are uncertain about what I mean by energy then have a look at this site.  

Now why do we have two different metals? Inside the squeezed lemon is a lot of lemon juice. There is a chemical reaction between the metals and the lemon juice. Because the metals are different they react with the lemon juice in different ways. The different reactions give the copper nail a positive charge and the iron nail a negative charge.

Connecting the two nails together with a wire will give you a flow of electrons in the wire from the iron nail to the copper nail. This will continue until the chemical reaction inside the lemon reaches completion.

Your normal battery is like the lemon but obviously made of different materials. Look at the diagram below.

Sadie, I hope you have found this useful. If you or any other reader would like to make a comment please fill in the Leave a Reply box below. And if you are uncertain about bits of the explanation please ask another question.

Additional note …copper nails are difficult to get hold of so why not use a small piece of copper tubing. Also there is a small possibility that a battery was produced over 2500 years ago, see The Baghdad Battery. Ask your teacher about it. Or ask another question.

Akshita (12) asks “In a circuit of 5 light bulbs and 2 batteries why do all of the light bulbs come on at the same time when you switch the switch?”

Hello Akshita, I asked my friends about your question.

Thank you team. You are right metals are much more important than the plastic coating. You could replace the plastic coating with paper or rubber or cloth BUT the metal has to be a metal. Why. It’s all to with things called electrons. Most elements

  • An element is a group of atoms that all have the same number of protons (positively charged particles) in their nucleus. Oxygen is the most abundant element on the Earth, Iron is the most abundant metal element.

have electrons that are tightly held by the nucleus but metals are different. The outer electrons of metals are rather loosely held by the nucleus and are free to move around within the metal structure. So if we looked at a circuit which was not connected to a battery (switch is Off) and looked closely at a small section of the wire you would see something like this …

The little red dots depict the outermost electrons of the metal atoms (the element nuclei are the positive circles).  You have to imagine that the electrons are constantly moving around within the metal structure and probably keeping quite close to their parent atom.

Now close the switch.

The battery is now pushing the electrons around the wire (- to +). This push is a bit like a long chain being pushed or pulled. All the electrons in the wire experience the push simultaneously (like the links in the chain) so when the switch is closed all the lights in the circuit will experience the ‘push’ and the electrons in the vicinity of the bulb filament will give up some of the energy of the push to the filament which will be converted to heat energy and create a hot filament which is then partly converted to light energy.

This is a lot to think about Akshita, you, and any other reader can ask another question or Leave a Comment in the Reply Box below.

Science Master Special – Energy

Thanks team. I would like to add a few things.

Firstly the list of different types of energy is not complete. If you can think of some more then ‘Leave a reply’ in the box below.

Secondly it is interesting how the energy conversions can take place. For example a microphone converts sound energy into electrical energy and a loudspeaker does the reverse process, it converts electrical energy into sound energy. Can you think of other examples?

Any reader can leave a Comment in the Leave a Reply box below

Makeda (7) asked “How does the electricity make a magnet?”

Makeda what a great question, and my answer is, I don’t know. We know that electricity can make a magnet or even give a wire magnetic properties. There are other things which we know but it’s a bit like gravity. We know that big things, like the Earth and the Sun attract smaller things – the Sun attracts the Earth, the Earth attracts you and me BUT we do not know what gravity is, we just know what it does.

So I asked my friends about this.

Absolutely, thank you friends. Electricity is linked to things called electrons that are attached to other things called atoms that make up all of the things that we see around us, and us.

There are some special materials that you might have discovered called ‘metals’. Metals allow the stuff which we call electricity to flow through them. In metals the electrons carry the electricity and when they start moving they not only start moving the electricity there movement creates a magnetic field.

So lets carry out some experiments to investigate electricity and magnetism.

Let us make a simple circuit with a battery and a switch  and add a compass, close to the circuit.   Why a compass? A compass is a very small magnet and will detect other magnets by trying to move towards them or away from them. Switch on the circuit and see what happens. Switch off and again see what happens.

 

Let us know what you saw.