“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.

Braiden (9) asks “What makes a diamond so hard?.

Braiden, my question (before I turn you over to my team) is how do you detect ‘hardness’? Can you create an order of hardness with some common materials?
Lets say:

wood (balsa)
wood (oak)
plastic object
bath sponge
china(cups and saucers)
glass
concrete pathway
cardboard
metal fork
coin
rock (sandstone)
piece of coal
pencil rubber 
For obvious reasons I have not included diamond in this list. I think that would be an interesting experiment to carry out. You will have to make sure it is a fair test 

Now over to my team.

Graphite has a layered structure with weak forces between the layers, This is a weaker structure than the close bonding of the diamond. The carbon atoms like the tetrahedral arrangement of the bonds with other carbon atoms. It is a very strong force.

Hope that makes some sense. If you have questions about the explanation please ask them. If you want to see my ‘hardness’ list go to Science Master Special-Hardness Results

Updated 15/1/2018  Experiment added.

Some questions on Gold from Chantelle (7), Shelby(9) and Mary(9)

Chantelle asked “Why is gold so hard to find?”

Shelby asked “Why is gold so heavy and hard to pick up ?”

Mary asked “Why is gold so expensive?”

Chantelle, Shelby and Mary some great questions , thank you. But are they science questions? Lets look at what a science question is.

science question is a question that may lead to an idea and help us in answering (or figuring out) the reason for some observation.

For example ‘Why is gold so heavy?” …so firstly let us look at what gold is. Gold is a solid –  Is it a rock? Is it wood? Is it plastic? Is it a metal? ……it seems to fit into the group called metals (it’s cold to the touch, it’s solid, it can be scratched, it’s shiny, it’s heavy) it’s a metal. So Shelby’s second question is a good science question.

Is it heavier than other metals?  It doesn’t seem to be heavier than other metals but how do I test this?  Fair tests are important in science investigations. Being fair I compared my gold with with metals of comparable size? It is heavier, why? Maybe the bits which make up the gold are heavier than the bits that make up other metals?

Chantelle. I think gold is quite easy to find compared to other metals. Lots of other metals, iron, silver, copper and aluminium exist as minerals  so they are quite difficult to find. What is a mineral? Look at the following page.

Science Master

 

“How does sound travel in things other than air?” asks Lilly(12)

Hello Molly, Science Master here. Lets’ check that we understand how sound is produced and what it is. Sound is a form of Energy ( see Science Master Special).  It is transmitted by particles hitting each other.

So what do you think? Could you hear the sound underwater?  Could you hear the sound further along the metal tube?

Lets improve the experiment by making it fairer. How could we do this?

Let us look at the particle arrangement in the air, water and metal.

The average distance between particles for a gas is 4 nanometers (1 nanometer = 10-9 meters), for a liquid it is 0.2 of a nanometer and for the solid 0.0002 of a nanometer.

So. If the first line of particles in the gas starts moving it has to travel 4 nanometers before it hits the second row. For the liquid this would be a smaller distance and for the metal it would be hardly any distance. What does that tell you about the speed of travel of sound?

Does your experiments support your thoughts? Maybe it needs to be modified? How could you modify it to really test your thoughts.

Just a thought of my own. The sound source (drum, spoon tapping, violin) gives the particles around it ENERGY. Those particles in air have to travel a long distance before they hit another particle and pass the sound on. All this time they are losing ENERGY. For the metal the particles only have to travel a little way before passing on the vibration.

(added 27/10/16)

Not sure of something Lilly…ask another question.

(Anyone reading this post who wants to ask a question or make a comment please feel free to do so)

“Why do metals always feel cold when I touch them?” asks Chen (8)

My question is, are the metals colder or warmer than the things around them? We need to test this question. So how?

We need find out if other materials behave in the same way.  We therefore need to test it with other materials, for example, wood, plastic, china and glass.

To make the test fair (an important part of my experiment) we need to make sure that all of the materials are at the same temperature at the start of the experiment. We can test this by taping a thermometer to the materials, leaving it there for a period of time (maybe 5 minutes) before touching each of them. Do they feel hot or cold? Do they feel like they are at the same temperature that you are.

What did you find out? If the metal, or other material did feel colder, or warmer, than the others then why?  Let me know what you think by filling in the Reply box below and post your comment or ask another Question . Anybody can do this.