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.

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.

Elizabeth (9) asked a question on lightning

Thanks team, some very interesting observations.

What I find interesting is how does lightning happen. It’s all about clouds. Hot weather produces lots of evaporation of water from our oceans. The hot air and water mixture rises, look at the clouds from a kettle. As it rises, the cloud of water vapour and air gets colder, and colder. The water turns into very small ice crystals which are still lifted by the cloud of air that they are in. As this happens it is thought that the ice particles separate ……. the lighter particles move to the top of the cloud while the heavier particles remain at the bottom.

The water/ice particles have a small electrical charge associated with them. When they separate the charge moves with them. It is likely that this causes an uneven redistribution of the total electrical charge. If you have more lighter water/ice particles at the top of the cloud than heavier ones at the bottom the difference in the total charges could be significant. So ‘flash’ they try to equalise and thus the lightning flash. It’s the process of the ice crystals at the top of the cloud trying to get rid of their excess electrical charge by giving it to the heavier ice crystals at the bottom of the cloud.

Sometimes difference in charge is so great that the ‘flash’ continues to the ground, but if you are in a storm and look at the flashes a lot of them are within the clouds themselves.

Elizabeth, sorry for such a long explanation. It was such an interesting question. If you have any other questions linked to what my friends and i have said please ask them.

Elizabeth. Some additional information ……. Look at this site. The type of electricity that is built up in clouds , before the lightning flash is static electricity. There are some experiments you could try.

Malina (13) asks – If blood has iron in it , is it magnetic?

Apologies accepted. Yes Malina, it was an interesting question.

What I need to ask you, is do you know about electrons? If you do then you will know that elements like iron are made up of atoms. Each atom of iron has a nucleus of protons (positively charged particles, 26) and neutrons (uncharged particles, 30) and surrounding the nucleus are the electrons (26 negatively charged  particles). It’s the way the electrons behave that makes thing interesting. In normal elements like carbon, silicon and sulphur all the electrons are ‘tied’ to the nucleus. They cannot leave the nucleus. In the metallic elements some of the electrons are ‘tied’ but the others are free to move away from the nucleus. This is why metals can conduct electricity (which is the movement of electrons along a metallic wire). It is the free electrons which dictate whether an element is magnetic or not.

Still with me? Hope so – if not you could ask another question.

The electrons themselves are like small magnets and some of them ‘pair up’ as magnets can do. For some elements who have an odd number of free electrons you end up with a lot of free electrons for the others you get complete pairing. See below  for a pairing image.

A metal is classified as ferromagnetic (very magnetic) if it has a lot of unpaired free electrons. iron and nickel are two examples.

When the iron atom begins to combine with other elements to form your hemoglobin there is further pairing of electrons between the iron atoms and the things it is combining with so it loses it’s magnetism.

That was a lot to understand. Hope you have managed.

Why does your hair stand up when rubbed with a balloon? was Kim’s question

Kim. I think we have something called ‘static electricity’ at work here. I asked my team to try to explain what ‘static electricity’ is.

As my friends have said we have met electrons before. These were moving  electrons. They were moving along a wire carrying their charge with them. Here we have electrons that are not moving, but they still have an electrical charge, so they are static.

Lightning is thought to be caused by static electricity collecting in clouds.

But now for your question Kim. When you rub your hair with a balloon. Some of the electrons are moving from your hair to the balloon. Or it might be the other way around …. some might be moving from the balloon to your hair. At the moment we don’t know which is happening. However whatever way it happens one of the objects (hair or balloon) loses electrons and becomes positively charged and the other object (hair or balloon) gains electrons and becomes negatively charged. Then we apply a famous rule about negative and positive charges …..like charges repel, unlike charges attract  soooooo  because we have a negative and a positive charge we have attraction. Your hair is attracted to the balloon, the balloon is attracted to your hair.

think you could work out a way to find out which of your two materials (hair or balloon) is the collector and the giver.

Two questions on electrocution and why does my phone get warm?

…. a couple of interesting questions. Which I will answer.

Electrocution is the term used to describe death from an electric current.

If you are going to die from an electric current it has to have certain properties. The voltage (or push) of the current must be high enough and the amperage (strength of the current) must be high enough. The electric current must also travel through the body in such a way that it passes through the heart or brain because it is those two organs that are most easily damaged by electricity (they both operate using electrical signals produced by the body). Electricity also has to have a pathway to the ground so if your feet are covered with an insulating material it might burn you (at point of contact) but is unlikely to kill you. To electrocute you the voltage could be as low as 40 volts and the current 500mA. Remember a battery can only produce a push of 1.5 volts and provide a current of 2000mA so even though the current is high the push is very low.

Mains electricity has a push of 250volts  and can provide a current of 13,000mA so it is very, very dangerous. Never, never, play with mains electricity.

Warm telephones are caused by your working battery. Your battery is pumping electricity around your phones circuits. That electricity is lighting up the screen, and converting your voice into electrical signals, and converting the electrical signals of the person you are talking to into sound energy and sending the signals. It’s doing a lot of work. You get hot when you are working and try to cool down, the battery gets hot and tries to loose that heat by warming up your phone.

Habid(10) asked “How do people make light?”

When you think about how we (people) make light you end up with quite a small number of possibilities. The obvious one is ‘fire’ then along came electricity which is ‘in a sense’ another form of fire. When it passes through very thin wires it makes them heat up, they glow red and then become ‘white hot’ and give off lots of light. When you pass electricity through some gases they ‘light up’.

Light remember, is a form of energy and can therefore be changed to other forms of energy. See the Science Master Special on Energy

Then there are the sources of light which are not made by people. How many of those are there? Go to the ‘Leave a Reply’ area below and tell us .

How did people find out electricity was travelling through the wires while experimenting with them?

Mo from 6K asked this question.

Mo, this is not a question that I am going to ask my friends to answer. I am myself, having difficulty in answering it. If there wasn’t this thing called electricity travelling from the battery to the bulb, the bulb would not light up.

What early experimenters would have found out was that electricity travelled best through metals. So what is special about metals? In 1897 (over two hundred years ago) a scientist called Thompson discovered a small particle called an ‘electron’ . It was found that all materials contain atoms, and atoms contain electrons but in metals some of the electrons are loosely attached to the atom. This allows the battery to push the loosely attached electrons from one metal atom to another thus delivering energy to the light bulb along the metal wire. For some thoughts on Energy go to Light and Energy

To test this create a circuit like the one below. Test different objects, like paper, rocks, plastic and the lead and wood in a pencil and the different metals, a coin, a bit of wire,  a paper clip ….. and find out if metals are really special.

As you ask more questions and find out more answers to your questions, by observation and experiment, you will begin to fully understand the above answer to your excellent question.

DO NOT TRY TO DO THIS WITH MAINS ELECTRICITY. IT IS DANGEROUS.

Abdur of 6K asked – If you had a solar powered light bulb and you were in a dark room, could you make a circuit with batteries and wires to make it work?

I asked my friends to look at this.

I liked the circuit that my friends made however ….just to let you know, the symbol for a solar cell is:

Which one do you like, the one my friends used or the official one? You can vote by clicking on the Reply button below and giving me your answer.

The really testing part of this experiment is where will you put the switch to test that the solar cell, in the dark, is not making the bulb light up? Unsure – then

REMEMBER DO NOT EXPERIMENT WITH MAINS ELECTRICITY.

Tabia (9) asks “Why do some circuits not work?”

Tabia, I asked my friends to help me with this question. They had some interesting thoughts.

What my friends have done is to create something called a ‘Short Circuit’. Because the electricity has found a much easier path around the circuit it does not pass through the bulb (where it would have to do work). It takes the shortest route around the circuit. Try making some of these circuits in school. Instead of a light bulb use a motor or a buzzer (do you know their symbols?). Maybe put a switch in the circuit so you get rid of the short route. Have you another question? Why not go to

and ask it. You could also try the Circuits Quiz.

DO NOT DO ANY EXPERIMENTS  USING MAINS ELECTRICITY.

Also

DO NOT USE RECHARGEABLE BATTERIES FOR THESE EXPERIMENTS (The battery will get very hot)

Mo (age 11) asked “Hi Science Master, how do people know metal is a good conductor and how did they find out it was a good conductor?”

Mo, I asked some of my friends about your question and they came up with some interesting thoughts of their own. Think about the comments and then look at my thoughts.

What is the difference in electrical conductivity of two different metals? Maybe you could construct a simple circuit with a battery and a light bulb connected by copper wire. You could measure how bright the light bulb was by using a light detector (you may have them in your school). You will have to decide how you are going to use the light detector to measure the brightness.

Now get some aluminium foil which is the same as the weight of copper (fair test) and use the foil to connect the battery to the light bulb and again measure its brightness. The brighter the bulb the least resistance there is to electricity moving through the circuit and the better the conductor.

DO NOT EXPERIMENT WITH MAINS ELECTRICITY

Do you know the answer to the question? If you do click on the Reply button below. Want to ask a further question?