Maya (10) asks “Neutrons, electrons and protons. What are they? Are they parts of an atom? Am I right?”

Maya, you are right. Neutrons, electrons and protons are all parts of an atom.
When do you think these were discovered? Let me show you the timescale

In 1808 a teacher and scientist called John Dalton discovered the atom.
In 1897 the electron was discovered by a scientist called J.J.Thomson
in 1911 the proton was discovered by a scientist called Rutherford
In 1932 Earnest Chadwick discovered the neutron

All this happened in 124 years! and the final bit ‘the electron’ was only discovered 87 years ago and you are now learning about it. I shall let my friends tell you a little bit about these particles.

 

Hamish Astra (11) asked “What are electrons and protons and neutrons made of?”

What a question. I suddenly feel very humble because that is a question that I should have asked myself but I never have. Thank you. I asked my friends to help me and here are the responses.

I have, discovered that electrons are still fundamental particles BUT they have found two types of electrons a negatively charged electron and a positively charged electron so they are now called leptons.  That does not however answer your question. What is a lepton made of?

My friends are quite correct Protons and Neutrons are no longer fundamental particles. (A fundamental particle is a particle that is not made of anything else) It was in 1911 that a scientist called Rutherford first discovered the proton and neutron. Then,in 1968, other scientists found that protons and neutrons were made up of fundamental particles called quarks. The next question of course is what are quarks made of?

To be continued

Is slime a solid or a liquid? asks Taya (11)

In development.

Hello Taya, many thanks for your question.  Slime is a fascinating substance and the best way of producing it is to mix a substance called Borax, with a substance like PVA with some water. There are other ways to do it but this is the traditional way. Is slime a liquid or solid?  How do we measure how ‘liquid’ something is. We use a measure of the way a liquid pours, or if you drop something (a small metal ball) into it …how quickly it falls through it. This property of liquids is called it’s viscosity. Like most scales of measurement there are usually two extremes  and something in the middle can have a little bit of both of the properties of a solid and a liquid – the slimes.

The Viscosity Scale was established by Newton in (would you believe it 1770 -almost 250 years ago). Slimes are registered as a Non-Newtonian fluids .

Why Borax and PVA? PVA is a substance called a polymer. A polymer is a long molecular particle of repeating units. Polymers usually quite happily slide over each other (not very viscous). Add borax and it’s molecules attach themselves to the PVA polymers and stop the easy sliding. Thus a slime is produced.

Uncertain about things in this answer. Please ask more. You can also look at this previous answer to a similar question.

If pressure on a gas is increased what will happen inter-particle force?” asks Prince (13)

Prince.  An initial answer.

You have to think of how you are going to increase the pressure of a gas.

I can think of two methods …..imagine the gas in a Coke tin. The gas particles are rapidly moving around, bouncing of each other and the sides of the container. We can increase the pressure by

(1) decreasing the volume of the coke can ….the particles therefore will hit the sides more often (increasing pressure) or (2) increasing the amount of gas in the can which again increases the number of gas particles that hit the side of the can, again increasing pressure.

In both these cases the intermolecular forces are quite small. Most gas particles are fairly inert , they have intermolecular forces but they are slight. Water H2O and NH3; (ammonia) are probably exceptional.

HOWEVER as you increase the pressure further the gas molecules have less room to move and they get closer to each other …the intermolecular forces increase UNTIL they are so strong (because there are so many molecules in the small space) that the gas becomes a LIQUID. This is helped if you reduce the temperature at the same time (molecular movement is temperature dependant).

 

 

 

 

Science Master

“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.

Liam (10) asks “Why does warm air go up?”

 

Thanks team. You are quite right we have to start at the beginning to really understand why warm air goes up. Let’s start by looking at what is air?

Air is a mixture of small gas particles (called molecules) of nitrogen, oxygen, carbon dioxide and some other gases. The image below could be a picture of what it would look like, if you could see it. What do you notice about it?

The red molecules are the oxygen, the blue the nitrogen and the others water and carbon dioxide. Imagine them moving around (I am trying to make an animation). Because they are moving they have energy.

If we heat the air, we are giving the molecules in it more energy. This makes them move faster and they move further apart.

The ‘thicker’ cold air surrounding the warm air drops into the space under the warm air and doing so pushes up the warm air which rises.

You can see this happening in a beaker of heated water.

Ronan (10) asks “How do stars form?”

Ronan ..this is my thinking about your excellent question.

Yes it is all about Gravity – There was a previous question by Tegan on Gravity. Have a look at it.

It is thought (it is therefore a hypothesis – an unproven idea)  that dust and hydrogen gas from the ‘Big Bang’ was gravitationally attracted to each other.

As the mass of the dust and gas got bigger it’s gravitational pull got bigger and the more dust and gas it attracted.

Eventually  the compact squashed ball of dust and gas started to heat up. It got hotter as it got bigger and eventually the particles of dust and gas began to break up in this hot environment and the hydrogen particles began to come together to make new particles … an atomic FUSION reaction began to occur and the star was born.

What does a dead star turn into? asks Liam (9)

Liam. Science is an interesting area of knowledge. It is recognised that it originates from an area of study called Philosophy. Philosophy (an Ancient Greek term) is about asking questions and for Science it is about asking questions about the physical and biological world. We ask the question and try to find the answers. For your question the answers are not easily found.

To try to answer your question, we have to know a little bit about the Sun. We know that in it’s centre there is an atomic reaction going on. It is not the type of atomic reaction we have in our Atomic Power Stations where we have an atomic ‘fission’ reaction occuring.

‘Fission’ means splitting something into two or more parts. The animation below shows a small atomic particle called a ‘neutron’  hitting a much bigger particle called an ‘atom’ . It splits forming more neutrons that hit other atoms, which break and form more neutrons………and on and on. This is a fission reaction and a lot of energy is released.

In the Sun the opposite is happening. Instead of fission we have fusion , the joining up of particles (Hydrogen atoms) to give Helium which creates lots and lots of energy. See the diagram below.

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Why would the Sun die? The main reason is that it runs out of Hydrogen. So what will happen then?  Firstly the Sun will get brighter. This will happen because of the helium that is produced. It will be pulled into the centre and begin to burn, adding more light and heat to the Sun’s radiation. Then as the hydrogen gets less and less the Sun will get cooler but at the same time begin to expand. It will become a Red Giant.

It is reckoned that it will expand so much that it will consume the Earth……that will happen in about 4 billion years time, however life on Earth will no longer exist in 1 billion years. This is because of the brightening of the Sun and the rising temperature of The Earth’s atmosphere, all the oceans will disappear and plant life will not be able to survive.

 

 

 

Mason (7) asks “Why is water wet?”

Thanks team. Let us start with a investigation. Let us look at the way water interacts with different materials.

 

Let us now look at the properties of water drops. Firstly let me define ‘cohesion’ and ‘adhesion’. The term ‘hesion’ means  … to stick. Cohesion is is the attraction and sticking together of the same things while adhesion is the attraction and sticking together of different things.

Look at the image of the water drop below. Each water particle is attracted to the other water particles around it , this is cohesion. Now add a different surface and the water particles are attracted to that rather than each other, this is adhesion. When adhesion occurs we get the spreading of the water drop and wetting,  providing the adhesive forces are greater than the cohesive forces.

So what about your investigation? Is there any evidence of cohesion or adhesion?

Here is a thought. it has been suggested that water is ‘wet’ because you can feel it’s wetness.

Maybe another little experiment.

You could let me know by clicking on the ‘Reply’ box below.

Science Master Special – Atomic Structure

This is a great video describing atomic structure.

And here is an example of the structure of an iron atom.

Note that most of the electrons are ‘paired’ with the exception of a few ‘free’ electrons in the outermost orbit.