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 
I think that would be an interesting experiment to carry out. You will have to make sure it is a fair test (science is all about fair tests …and questions …and hypotheses and experiment). How will you carry out the experiment? ( a hypothesis is an idea – “I think soft things will float, hard things will sink”)

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

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

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)

“What was the first plant that ever grew on Earth?” asks Mahdiyat (8)

So what now? Thanks team, some good answers.

It would be great if we could do some small investigations using Moss.

1.Firstly let us confirm that the moss has no stems or flowers.

2. Secondly a more long term experiment. Try ‘planting’ your moss on a rock. Before planting look closely at the surface of the rock. compare the surface 6 months after planting (and not disturbing the Moss).

Now a story ……..

The moss was the Earth’s first plant and it took over the world. It damaged the rocks it settled on and it took all of the Carbon Dioxide out of the atmosphere. This made the Earth very very cold (the first ice age). The coldness killed most of the moss and as the Carbon Dioxide built up again it allowed other plants to share the Earth with it.

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

“Why does my banana skin go brown when I peel it off? asked Gina (10)

Gina, it seems to be something about the ‘breaking’ of the skin of the fruit, which lets  in oxygen and allows it to react with some of the fruits chemicals.

We could test that idea. One way to test it might be to try and stop the ‘breaking’ of the skin of the banana. Can you think of a way of removing the skin without breaking or damaging it?

We could also test the role of oxygen. Any ideas how? If you have an idea why not try it  by comparing the speed of ‘browning’ for your oxygen and ‘no oxygen’ banana skin?

Remember to try and make the tests as fair as possible. Think about what that may mean. Remember a fair test means only changing one thing at a time while you try and keep all other things constant.

Let me know how you got on by Leaving a Reply in the box below.

Preethikha (13) asked a question about planting corn seeds in clay.

Preethikha you asked your question on behalf of your friend  Johan who appeared to be having trouble in growing his corn seeds in clay. I asked my friends about this and these were the ideas that they arrived at. 

The roots of the corn plant are very complex like most plants and they NEED oxygen . Clay is an important soil, it is full of nutrients which are important in providing the growing plant with food , HOWEVER  it is very different from most of the soils that we meet in our gardens.

Soils are composed of three types of particles: sand, silt, and clay.

The size of the particles varies, with clay having the smallest size and sand the largest.Smaller sized particles pack more closely together and slow the flow of water through the soil.The composition of a soil can affect the permeability (flow) of water through it.

There is the possibility that your friends corn seeds produce roots which are then ‘drowned’ in the surrounding clay soil. Investigate your friends soil and compare it to other soils in your neighbourhood. My next question for you is how would you go about investigating it ?

 

James asks “What happens to the cactus flower the day after it flowers?”

Many thanks team you are right. The cactus needs it’s flower to be pollinated.

What do I mean by pollination?

Lets look at that picture more closely (see below). Pollination is the process of transferring a pollen from the male part of a plant (the anther) to the female part of the plant (the stigma). It is better that the transfer process is from the male part of one plant to the female part of another similar plant.

What helps this happen – Bees, flies, bats and lots of other insects.

What happens then – A fruit develops from the flower site and in the fruit are seeds, lots of them. These fruits are eaten by animals and by this method the seeds are spread around the surrounding environment.

What experiments could you think of to test these thoughts (hypothesis)? Any idea then click on the ‘Leave a Reply’ button below.

“I know I can see myself in a mirror but why cannot I see myself in other things?” asks Isabella (8)

Many thanks team. I have some ideas about investigations that you could do at home. People say that light travels in straight lines. How can we test this idea. Firstly we need a source of light. How about a torch. 

Now we know that a torch sends out light in all directions but how do we know if it is travelling in a straight line? Think……..

Now lets ‘capture a little bit of the light from the torch. Let’s use a piece of card with a hole in it and see if we can make the light from the torch go through the hole.

Now what do we have to do to show that, the little beam of light coming through the hole is travelling in a straight line?
Supposing we had another piece of card with a hole in it in exactly the same spot do you think you could arrange it so that the little beam of light goes through the hole in the new piece of card?

Do the same for a third piece of card arranging it so the little beam goes through it’s hole. Now draw a line between the torch and the third hole. What do you notice?

Now lets quickly look at your question about not seeing reflections in materials that are not mirrors.

Reflections are wonderful things and they happen, or do not happen because light travels in straight lines. A reflection occurs when a beam of light bounces off a surface. You could set up your torch and card above to make a reflection, using a mirror or something flat and shiny.

Now do the same for a different type of surface.try it with a piece of material. What happens? Try with all sorts of flat surfaces – shiny metal (use flat aluminum foil and then crinkle it), cardboard, paper, plastic, water, leather……..
What do you notice? Maybe reflection requires a flat shiny surface? Think about the results.

“How do you measure the distance to the Sun and stars?’ asked Julian (12)

 

Julian, quite a challenging question. I will only be trying to answer the first part – the Sun-Earth distance and the Earth-Stars distance.? Even then as my team suggests, I might be introducing mathematical terms that you have not met yet, but I have included links to other sources of help.

To answer the first question I recommend you read a Universe Today article   It is an excellent historical review of the problems that the early scientists had in determining the Earth-Sun distance. The answer finally came from observations of the movement of the planet Venus across the face of the Sun. In it the writer refers to a Nasa document that tries to explain the methods used. In present times the distance to the Sun is measured by ‘bouncing’ a radar pulse of of it.

Determining the distance to the other stars becomes possible once the Earth-Sun distance was known. It uses a technique called parallax.  I would like to illustrate this with a question which tackles a simpler problem. ‘How far is my finger away from my nose?’

Try this little experiment, put a finger in an upright position in front of your nose. Now close one eye and note the position of the finger. Close that eye and open the other one. The finger moves! Now suppose, with help, you could measure the amount of movement. You could end up with diagrams like those below. Did you make a note of the position of your finger relative to your nose? No – you can now see how you could work this out.

Now let’s do a little geometry and add an axis

We can then measure the angle of the apparent movement

You end with a right angled triangle ABC, knowing the angle x AND the distance between your eyes you should be able to do a bit of trigonometry using TAN x = opposite/adjacent (Tan x = AB/BC) and work out the distance of your finger from your face. For an introduction to trigonometry please look at this site.

Amazingly this is (in a crude way) the same process by which astronomers can measure the distance to the stars. Instead of using the distance between your eyes they use the orbit of the Earth. They look at a star and make a note of it’s position and then do the same thing 6 months later when the Earth is at the opposite side of the Sun. They therefore have AB (the distance between the Sun and the Earth and they have the angle through which the star has apparently moved. 

This gives the route to determining the distance between the Earth and a Star.

 

(revised 14/05/17)