Tiago (?) asked “Why are beach sands so different in colour and size?”

I asked my friends about this but they were more interested in investigating sandcastles than trying to answer the question.

It most certainly is something to do with the water. Water wet’s most things.There are some things that water doesn’t wet. Things which are wetted by water are called hydrophilic while those that are not wetted by water are called hydrophobic.

Sand is hydrophilic so water can act as a sort of glue between sand particles, holding them together. It’s not a very strong ‘glue’ but it is enough to stop the sand particles falling apart in the sand castle. For more on this look at this previous question. Some scientist have done some research and found that you need between 1% of the mixture to be water to keep the sand together. T

There is, however, the small problem of the type of sand. There are lots of different types of sand. Sand comes from broken rocks and animal skeletons. Different rocks and skeletons change the colour of the sand. The most common sand is from quartz rock (SiO2) 

Black sand comes from eroded volcanic material such as lava, basalt rocks, and other coloured rocks and minerals, white sand was once the skeleton of animals, shells or coral reefs.

Sand is formed by the action of the sea on the rocks, constantly moving the rocks and breaking them. It is thought that the flatter the beach the smaller the particles of sand are. For steep beaches the sand particles are larger. It is something to do with wave motion.

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.


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.

“How is porcelain made?” asks Kaia (8)

Thanks team.There has already been a mention of kaolinite in a question on minerals, see this site.  My team are correct, the difference between ordinary clay pots and porcelain pots is the temperature at which the clay is ‘fired’.

The ‘firing’ process  is linked to the temperature of the kiln.

So a porcelain pot is a pot heated up to much higher temperature than that of other pots. This causes the clay to form a new mineral called Mullite.

For more ‘hardness’ information you can go to this Science Master Special.

Updated 15/01/18 Experiment added.

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)
concrete pathway
metal fork
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.

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.

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

Liam (7) asks “What causes an earthquake?”

Thanks team. When the Earth cooled down the crust was formed over the whole planet.

However, after the crust was formed there was still a lot of activity in the molten core of the Earth. This caused cracks in the crust and it is these cracks which are the cause of Earthquakes. Scientists have investigated the cracks and created a map of where they are.

You can see these in the maps below.

The lines indicate the cracks on either side of our Earth. The spaces within these cracks are called  ‘plates’. These plates are constantly moving (very, very very slowly).

Any idea what is making them move?

Some plates are moving away from the plates next to them BUT that means they are also pushing up to other plates on the surface. It is this movement that causes the earthquake.

Where do you think the earthquake happens …is it in the middle or outside of a plate? Where is your country?

I have created two jigsaws of the Earth images above. Print them, stick them on some cardboard, and cut them out and make your own world of ‘plates’ and try moving them.

Link to Jigsaw 2

Link to Jigsaw 1

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

“Why do volcanoes erupt?” asks Silas and Zakk (10)


Thank you Silas and Zakk for your question. My team are correct it’s all about pressure. All volcanoes have a thin ‘lid’ of solid rock which which is solidified magma. Underneath the lid is lots of molten magma which is heated by the Earth’s central core.

Things can happen to this magma. Some of it could cool, and solidify. You could also get convection currents like you do in any hot liquid. These can increase the pressure (push) on the volcano lid, break it and the pressure is released like the liquid in a bottle of fizzy drink.

Want to make a comment, please make it in the box below. Not sure about something …ask another question.
(Anyone reading this post who wants to ask a question or make a comment please feel free to do so)

(revised 13/9/17  Magna misspelling and added support text)

“How many particles are there in the Earth?” asks Ravindra (11)

Wow what a difficult question. I will ask my friends to try and answer this question.

A ‘particle’ is a tiny bit of something. So Ravinder, well done, you have asked a question that I or my friends cannot answer. Try and ask some more.

Any reader can ask another question or leave a Comment in the Leave a Reply box below