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.

 

 

 

Liam Astra asks “Why does Mentos lollies make coke spurt everywhere?”

Liam, thanks for the question. Are you sure that you wanted to talk about Mentos lollies? I couldn’t find any mention of them …..only sweets …so I have focussed on them. 

Let me start my answer by showing you my favourite clip of the Mentos/Diet Coke reaction.

My first question is ….is there anything special about diet coke and the Mint Mentos tablet?

Firstly there is evidence (somebody has done some experiments) that diet coke contains more carbon dioxide gas than ordinary coke. When they make coke they add carbon dioxide gas to it. Lots of gases are absorbed by liquids. Oxygen gas is absorbed by water…..this allows fish to breathe. The manufacturers add carbon dioxide to the coke because it enhances (makes better) the taste of the coke. Carbon dioxide, like oxygen is a safe gas  – it is the gas that you and I breathe out – it is created by our bodies.

Experiment 1.  Add a Mentos to a bottle of Coke and one to a bottle of Diet Coke….is the reaction the same? Make sure that it is a fair experiment (talk with others about how you can make it fair). Make sure that it is a safe (if you have them wear goggles) and a tidy experiment. (think about your parents or teachers)

Experiment 2. Now let’s look at the Mentos tablet. Is the tablet smooth or rough to the touch? Try and find something (maybe an adult can find you a little bit of sandpaper) that will change the surface of one of the Mentos tablets (more rough or more smooth) and drop it into a diet coke bottle. What happens? Do the rough and smooth tablets both give exactly the same ‘spurt’?

You could also carry out this experiment with Fruit and Mint Mentos tablets?

Here are some magnified photographs of the surface of a Mentos tablet.

 

So what have we found out? What has roughness to do with surface area? Why does the dissolved gas decide to come out of solution when it meets the tablet?

Let me know your thoughts in the box below.

Viper Astra (9) asks “What makes earthquakes happen?”

Viper, to answer your question it might be useful if we go back to the beginning. By the beginning I mean 4.6 billion years ago when the planet was first formed. Then it was a ball of molten lava. (1 billion is 1,000,000,000 or one thousand, million)

Over the next billion years the planet cooled and bits of crust formed on its surface. We call these bits of crust tectonic plates (the word ‘tectonic’ comes from the ancient Greek word for ‘building’ ……the crust is ‘building a surface’). These bits of crust got bigger, sometimes sunk into the molten sea they were floating on, but slowly covered the Earth.

Because they floated, the ‘plates’ of crust would have constantly experienced the movement of the molten ‘sea’ below them, so they moved and bumped into each other, and they are still doing that today. It is the movement and the, bumping into each other that causes earthquakes.

Watch this short video. It explains the different types of earthquake that can occur.

Thanks for the question Viper. Not sure about something then ask another question.

What natural phenomenon made the Mariana Trench? asks Sabine (9)

The Mariana Trench ….. I have been thinking about this and I think, worked out a way of explaining the answer to your question.

Firstly

Our planet, the Earth, is an interesting planet. It has a solid surface (we call the crust) that surrounds a molten (liquid) inside, called the mantle. Like a boat on water the surface floats on the molten liquid interior. Look at the image below:

Many millions of years ago the planet was just a hot molten sphere. Slowly the crust began to form. It didn’t all form at the same time so it became a little like a cracked egg shell with each bit floating and moving on the molten mantle. These pieces were the tectonic plates. The image below shows you the present positions of the tectonic plates.

You might be able to see what tectonic plate you are living on.

These plates are constantly moving (very, very slowly). When they bump into each other they can cause lots of problems, like earthquakes. The Philippine Plate and the Pacific Plate bumped into each other many millions of years ago  and this made the Philippine Plate sink below the bigger Pacific Plate …. and the result the Mariana Trench. See the diagram below.

Where is the Mariana Trench?

I hope this makes sense Sabine. Feel free to ask another question.

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.

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.

Lexi (9) and Jaeda (9) and Cadence(8) asked a question on “Minerals”

Lexi, a nice question, a lot of elements are found within the form of a mineral. I shall let my team introduce the answer to this question.

Jaeda. You asked a question on crystals and why are they so expensive. This is not  a science question however most crystals are minerals so this question is also addressed to you.

Cadence . You asked about talc, which is a mineral.

All minerals are found in rocks. It is thought that some are created by the magma (lava) from volcanoes while other were formed in the Earth’s mantle and have reached the surface through earthquake activity. The minerals created from volcanoes have smaller crystals (probably cooled faster), minerals created more slowly in the mantle consist of bigger crystals. All of the minerals are created by a chemical reaction.

A lot of minerals are mined, dug from underground shafts. A lot of minerals have the elements Silicon and  Oxygen in them.Talc is a mineral of the elements Magnesium, Silicon and Oxygen and is mainly found in Japan and the United States.

Have fun and watch this video on minerals.

Thank you Lexi, Jaeda and Cadence. If you want to comment on this post please feel free to do so in the Reply box below. Or why not ask another question.

Could the Earth’s core be hotter than the Sun? asks Brooke (9)

Brooke. When earthquakes occur ( For how they occur see this question) you get a seismic wave travelling outwards from where it occurred. Imagine an explosion, a rock cracking a noise bigger than anything  you have experienced.  It would create the biggest sound ever, shake the ground more than it has ever been shaken and send a signal to the rest of the Earth that the earthquake had happened. It is this seismic wave of spreading energy that has helped scientists discover the structure of the inner Earth. The waves spreads out in all directions and some of them pass through the centre of the Earth. If you look at the waves on the other side of the Earth you can examine them and find out what they have travelled through.

It is now thought that the temperature of the inner core is close to 7000 degrees K (Kelvin). It is however not a liquid , because of the pressure of all the stuff on top of it. It is therefore a solid iron core at about 7000 degrees K…which is close to the outer temperature of the Sun.

(0 degrees K=273 degrees Centigrade so 100 degrees Centigrade = 373 degrees K )

William (9), Erika (10) and Alissa (10) asked some questions on fossil fuels

Erika asked “Why are fossil fuels so expensive?”

Alissa asked “How were fossil fuels found?”

William asked “how is oil made?”

I asked my friends to to talk about this however firstly I would like to talk about what makes a good science question.

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

Erika’s question is a good economics question.

Miners (those who look for oil and coal) have a variety of clever tools to help them find the fossil fuel. For example they can use ‘sniffers’. The  sniffers can detect small amounts of oil vapour which might find their way out of the rocks that are hiding the oil. They also use seismic detection methods. Seismic waves were used to investigate the Earths core however the oil explorers do not use earthquakes to create the seismic wave – they use special guns or explosives. The shock waves (seismic waves) travel through the rock and at some point they are reflected back and return to the surface. The waves are recorded and examined and they tell the explorer what type of material (rock, water, oil, coal) they have traveled through.

So the question from William has led to further observations and thoughts which lead me to another question……If I left my garden rubbish for a year would it turn into coal? If not why?

Edited 20/10/17 – image changed, link added and seismic waves discussed