“How do people survive in the jungle?” asks Lachlan (8)

Thank you team, for your comments.

You are right Homo Sapiens survived because of their hunting and gathering skills.They were better at it than their fellow humans  Homo Neanderthal and the other human groups (Homo erectus, Homo ergaster, Homo rudolfensis …..)

Some clever people have found, that we still have hunting and gathering skills in our blood. So there you are, we will/might be able to cope in a jungle environment.

Revised 11/11/17 – added other homo species.

“Why does the sky go green when it hails?” asks Swifty (11)

What a question? Thanks  team for your thoughts. To me it seems to be a unique mixing of the colours from our sunlight. We know that the blue sky is because of the blue part of the spectrum of colour that comes from the white light from the Sun.

Some of the blue part of that spectrum of light is scattered when it hits the molecules of Oxygen and Nitrogen in Earth’s atmosphere. So blue coloured light illuminates the daytime sky. We know that when we see a sunset we can see a red sky in the distance and that is because we are looking at the Sun through a lot more atmosphere than we would do in a normal day. I attach a NASA video that explains this then I will tell you my ideas about a green sky.

My thinking, and that of some others, is that the green sky is linked to the storm clouds (the background image above, was a pause in the hailstorm that the cyclists were experiencing). These were preventing some of the sunlight reaching the viewer who saw a yellow light mixed with the blue sunlight. the mixture of these lights could have caused the green light (a cyano type of light).

Very happy to hear comments and questions. Remember science development is about admitting your ignorance and my thoughts above are just thoughts. You and I need to do some further investigations.

Keith (13) asked a question about thermal papers in cash machines.

Keith’s question
More and more places are using thermal paper as a form of receipt paper for customers. With time the information fades. How can one scientifically go about recovering information which may have faded from thermal paper.

Keith, many thanks for the question. I never realised that thermal(heat sensitive) paper was used in so many places and that it is also the basis on which the polaroid camera worked.

Thermal paper is made using a collection of dyes which exist as colourless crystals that become coloured when they interact with an acid.


For those who enjoy their chemistry you might have come across adding a dye called phenolphthalein to an acid solution. The dye changes from colourless to a deep purple.

The applied heat (from the cash register machine) melts a layer in the paper which contains acid crystals. The liquid acid then interacts with the layer below it which contains a colourless crystalline dye which changes colour as the acid interacts with it.  The print then shows. The acid quickly becomes crystalline again.

Over time the print does begin to disappear.

A little investigation.

Obtain an old till receipt which your adults do not want to save. Put it onto an ironing board and with a hot (care) iron, iron it.

Stop

To make it more scientific predict what you think might happen before you carry out the experiment. Any ideas, if so you have a hypothesis.  Now find a very old (fading) receipt and using a hair drier blow warm air onto the BACK of the receipt. Again predict.

I think I’ll stop there. Many thanks for the question Keith. Please comment or 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 
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

“How did evolution happen?” asks Parm (10)

 

Parm, it’s all due to some wonderful stuff called DNA however the beginning of life is at the moment attributed to  a simpler chemical called RNA. Somehow 4.5 billion years ago, in a hot chemical quagmire a collection of complex chemical structure was formed which was living, it could reproduce itself. It is thought that this microscopic entity was quite close to the structure of present day bacterias although, it’s make up was completely different. For example it didn’t breathe Oxygen, it is thought that it might have breathed a chemical called Ammonia and it expelled Oxygen. It also, in its structure contained a crude DNA structure.

From this humble beginning all life on Earth evolved dictated by changes in the  DNA molecules that were part of their structure. Plants, Insects, Bacteria, Animals, Fungi, Algae,  all life contains their own DNA molecules which dictate their continued existence.

So for Jeremey, our snail there has been, for some reason, a small change in her/his DNA. The spiral is wrong. Maybe it might be wrong but it might help Jeremy eat a plant that he/she couldn’t eat before and therefore survive and breed more snails like him/her.

Over the millions of years that life has existed on our Earth, now and then, new life , created by old life, experiences a slight change in the DNA, and that means that the new life is slightly different from the life of its parents (plants, animals, fungi ….). If the new life survives, that life will create more new life in it’s form, evolution has taken place.

Hope this makes sense Parm. Any thoughts? Write them in the ‘Leave a Reply’ box.

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.

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)

“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)