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

Laura G (10) asked “Is it possible to collect condensation to water a garden?”

Laura, have you ever on a warm day noticed faint water droppings on leaves of some of your plants. Where has this water come from? It might have come from the leaf itself or alternatively it might have come from the atmosphere. The atmosphere/air around us can hold an immense amount of water in its vapour form. For example a parcel of 1 cubic meter of air at 30 degrees centigrade could contain 28g ( or 28 cc) of water. There is therefore a good chance that those drips on the leaf came from the atmosphere.

The fog fence provides a surface that is colder* than the air around it and therefore a place where water vapour can condense and the water collected. The water can then be used for irrigation of plant life AND the plant life itself generates it’s own water vapour so it is possible to use a fog fence , in a desert like area to collect water, feed it to plants and begin the process of creating a self sustaining green environment.

I am happy for suggested revisions to the above arguments.

*Sorry Laura,I have given you a completely wrong bit of information. It is very unlikely that the fence would be at a different temperature from the air around us. So how does it aid condensation?  It’s made of metal. What do you feel when you touch a metal object that has been lying around on your table . It feels cold. Why? It should be at the same temperature as the rest of the objects on the table. It feels cold because metal is a good conductor of heat and as your fingers are quite warm it conducts the heat away from them and they feel cold. Maybe the metal in the fence is conducting heat away from the water vapour and because it loses heat it changes from the vapour form to the liquid form …..condensation.

Para added 15/10/17

“Why do stars twinkle” asked Mia (8)

Many thank team. I think Mia has all she needs for a little bit of experimentation.

Mia, in a darkened room , put the aluminum foil on the floor, place the bowl over it and shine the torch onto the bottom of the bowl.

What do you see?

Now add some water to the bowl(about half full). Let the water settle and then shine the torch onto the bottom of the bowl.

What do you see?

Finally, still shining the torch onto the bottom of the bowl give the water a bit of a vigorous stir with a spoon or even the end of a pencil.

What do you see?

Is what you see when the water is moving different from when it is not moving? Maybe the moving water is a bit like the moving air through which you are seeing the stars.

Tell us what you see. you can do this in the Reply box below.
(Anyone reading this post who wants to ask a question or make a comment please feel free to do so)

A question “How does the world work”

Some time ago a well known scientist (James Lovelock) suggested that the Earth (our planet) was special. He claimed that the Earth itself was a living thing and had control over its environment. He gave the Earth the name Gaia (a Greek name for the goddess of the Earth) and suggested that the planet’s objective was to support life on it, at all cost.

It has been argued, by those who support this idea, that there is a lot of evidence from investigating the Earth’s history over the last 3 billion years, that suggest the idea is valid. Below are some of those arguments. What do you think?


Note
The Gaia idea is something called an hypothesis (an idea). It has yet to be proven. If proven it can then be called a theory.

 

“When you shake a fizzy drink that is full when you open it and it explodes?” asked Ruby (8)

When you open the bottle you should hear a gentle fizz. When you pour the drink into a glass you get a bigger fizz and lots of bubbles. If you had ice in the glass you would get even more bubbles. This is because the surface of the glass and the ice cubes are full of little gullies and points. The gas bubbles that were hidden in the liquid attach themselves to the gullies and start to get bigger, (bubbles grow by being joined by other bubbles) and bigger and then when they are big enough, because they are lighter than the liquid, they rise to the surface.

Here is a little experiment for you to try —put the ice cube in your mouth and get your tongue to smooth it, for a few minutes. Think about what I have said and try and predict what the outcome will be when you pour a new bottle of drink over it. Now add the carbonated drink and test your prediction.

Now what happens if you shake the bottle before opening it. This is where you get the explosion!  Here is my possible explanation……. look at the bottle of drink.

(1) There is an empty space at the top of the bottle. It’s not empty, it is full of Carbon Dioxide gas.

(2) When you shake the bottle that gas mixes with the liquid and because bubbles attract other bubbles the gas in the liquid becomes more bubbly.

(3) The bubbles that were hidden in the liquid join the new shaken bubbles. Undo the top and these new bigger bubbles all escape at the same time pushing the liquid before it – the  explosion.

Look at this previous post.

 

“Why does a coke can explode when a mentos goes in. Is it a chemical reaction or just fizziness?” asks Bella (8)

Some good observations . The bumpy surface is the real reason for the fantastic reaction between the coke and the mentos.

Think about the coke. It is a fizzy drink. How has it become fizzy? In the making process a lot of gas (Carbon Dioxide) is dissolved in the coke under high pressure . Water has lots of air dissolved in it. There are quite a few liquids that can absorb gases.

So what happens when the mentos is dropped into the coke? It’s all to do with surface. If the mentos had a completely smooth surface, like the inside of the coke bottle very little would happen (you can test this). However look at the image above, the mentos tablet is covered with valleys and holes. Each of these sharp points is a place where a bubble of the gas absorbed in the coke can attach itself to and therefore remove itself from the coke liquid. 

The gas bubble is lighter than the liquid coke, so what does it do? It moves upwards (it’s lighter than the liquid so it floats). Millions of bubbles begin to move upwards. What is in their way? Coke liquid.

There are lots of things to investigate here. Start doing some science. Do shiny things create bubbles? Do the number of mentos tablets increase the explosive effect? How can you measure it fairly? Does the temperature of the coke affect what occurs.

Have fun but test the ideas that I have presented you with. Science can be fun. If you want to ask another question, do it. If you or any other reader would like to make a comment use the ‘Leave a Reply’ box below.

Sorry I forgot one of your original questions. The bubble forming and bubble emission processes are physical and not chemical processes.

 

Clara (8) asked -“Does sound only travel in air”

soundtravelling

A great question and some interesting comments from my team. I think we need to carry out some experiments to test the ideas that my friends have.

Firstly we know that air can carry sound. To consider the radiator pipe idea we need to get a tube of metal and see if, on it’s own, it carries sound. tap one end of the tube and put your ear on the other end. record what you hear. Now fill the tube with water and repeat the experiment. You could also get a rod of metal, with no air, no water and test that. If you had a sound sensor(your school might have one) you could measure the amount of sound that a solid rod, water filled rod and air filled rod carry. Which was best? How did you make the test fair?

The string telephone could be another example of sound travelling from one place to another without using the air. Try to make ‘telephones’ that are ‘sound proof’. For example make sure that when somebody is speaking into the mouthpiece they cannot be heard speaking by those standing around. No ‘air’ sounds. to do this you might have to modify the mouthpiece. 

Try this video for further information. If after watching it you have any further questions  ….THEN