Sheereen asks – “Where do the items that a black hole suck up, go to?”

Sheereen, I was always told that a Black Hole was a place where my money or lost items apparently disappeared without trace. But I think your question deserves a different answer. I asked my friends about it. I shall also ask them to avoid science fiction stories where Black Holes seem to be used in a variety of stories. Do Black Holes really exist I might ask?

blackhole

My friends are right. The denser (more compact) the mass (think about mass and weight) of an object the greater its gravitational pull. So when the Sun collapses into itself you have a object that gets very small and very, very dense so it’s gravitational pull increases and it begins to pull everything in towards it. when something is pulled into it (including light) where it goes to is a mystery. It may add to the mass of the collapsed Sun and make a stronger black hole by increasing the gravitational pull. OR as the Science Fiction writers would suggest it takes you to a new dimension. Thank you for your question Sheereen.

Rainie (8) – asked “How do touchscreens work on phones?”

Rainie – what a question!  I thought I would start by presenting my team with the question….

touch

Rainie it’s all about electricity. Think about the ‘stuff’ that comes from batteries that makes your watch work or makes a torch light up the world. Electricity travels from place to place by travelling through things that allow it to travel through. It cannot travel through paper, plastics, stones and other things. It can however travel through water, some special glass, metals and you.

When you touch the screen of your telephone, you are allowing a very small amount of electricity to travel from the glass to you. The phone recognises this and knows where you have touched the screen. It then responds to the touch.

An experiment – touch the screen using a variety of materials on your finger. Try a damp finger, a finger covered by cloth, paper, aluminium foil, plastic and maybe a leaf. I am sure you can think of other materials. This little experiment might lead to other questions so please ask them.

Remember Rainie do not under any circumstances play or experiment with mains electricity. It could hurt you badly.

Ash asks “Why do we need academic learning, what is it’s purpose?’

Ash. This is a question I will try to answer without the help of my friends. It was a challenging question. This is a personal view.

I have tried to attempt academic learning for most of my life. Notice the word tried. Academic learning for me is learning things that would help me solve scientific questions. I learnt about materials and then about atoms and molecules and their properties and then about ideas on how this dictated the way in which they behaved. I then used this to help with my own ideas.

There are however lots of different forms of academic learning in all subject areas. Think of the people who are interested in history. Their learning could involve studying and interpreting lots of old and ancient texts – or modern ones. Does history help us in understanding what is happening in the world today?

Think of the engineer who would like to improve the jet engine. Look at the learning that she/he would have to do to help them solve the problems that jet engines might have.

Don’t however, in your life, avoid the other types of learning. Learning by listening, learning visually, and learning through actions are just as important.

Now and again academic learning involves tests, class test, school tests, national examination tests. They are horrible but on the other hand they help you in the steps of the academic learning that you go through.

Fatemeh asked a question about springs – in vacuum cleaners

Fatemeh asked the following question – “When you want to use a vacuum cleaner, you pull the wire out until you got the length you needed. The the length of the wire gets fixed. Then, when you want to rolls up the wire, you pull it out a bit and then you release it,it rolls up with the power of hands only.”

Fatemeh, I think this is a question about springs. To give me time to think I passed the question to my friends.

springs

Many thanks team.

Fatemeh. I suspect the vacuum cleaner observation is linked to springs. When you pull the power lead  out you are likely to be extending a spring. Your energy which you apply to pulling the power lead is being stored by the spring. When you stop pulling a device within the vacuum cleaner is applied to stop the spring from unwinding and losing it’s stored energy (the proper scientific term is stored potential energy)  …….until you give another little tug which releases the device and the stored energy is then used to pull the lead back into the vacuum cleaner.

To experience the way in which a spring can store energy try making one yourself from a paperclip. Get a big paperclip and try to wind it around a pencil.

paperclip-spring

Charlotte asks the question “How does gravity hold you to the ground?”

Charlotte I can honestly say that I have no idea how gravity holds things down. I have asked my friends and await an answer.

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Charlotte, my team seem to agree with me. In the 17th Century Newton and another scientist called Hooke did some great observations and experiments on falling objects and proposed that gravity was an attraction between any two masses AND the attraction was dependant on the size of the masses involved. For example you are attracted by the Earth and the Earth is attracted by you BUT your attraction is so much smaller than that of the Earth it does not affect the motion of the Earth. The attraction between you and the Earth is also dependant upon how far away you are from the Earth. The Moon is attracted by the Earth and the Earth is attracted by the Moon. They are both big bodies so gravity does affect the way they move with respect to each other and this dictates how the Moon orbits the Earth.

Some scientists including Einstein have put forward ideas on how gravity operates but even these are being challenged. There a lots of things which are still unanswered. The question just has to be asked.

Charlotte, the Earth’s circumference can be calculated by multiplying the diameter of the Earth by pi.(π)

Marcus (11) asks – “How does our brain control our body”

Marcus. Many thanks for your question. I must admit that I am happiest with questions relating to the physical world rather that the biological world. But like a good scientist I was curious so I asked my friends to tell me about how the brain might control the body. For once they came up with some answers.

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This is certainly interesting. for the brain and different parts of the body to contact each other they use nerves (bit like wires), they also use electricity – but a different type of electricity to what we usually meet The nerves use positively charged particles to send the messages, we in the real world, use negatively charged particles.

I found out that there are two types of circuits. Some are linked to things that the brain has put on automatic and some are linked to response/reply circuits. These are the autonomic nervous system and the others are the ones which your brain can control are called the somatic nervous system. Can you draw up a list of the autonomic  functions that you brain controls. How many items do you come up with. Want to let me know click on the Reply button below or leave another question. Thanks for the question.

Mara (11) asked a question about elements and why they exist in different states at room temperature.

Mara’s question was “Why is it that some elements are Gases or Solids at room temperature? I can understand why we would need them to be different, and my first guess would be that the density of the element is the answer, but I don’t know how that would work. So I wonder how is that some elements are different at room temperature, and why aren’t they all solids or all gases?”

Mara, many thanks for an interesting question. I asked my friends about this and your ideas.

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Some thoughts. I am thinking about the individual ‘atoms’ that make up the structure of an element. For Hydrogen you have two atoms joined by a bond, and the attraction between each Hydrogen molecule (the name given to bonded hydrogen structure) is very small. For the element Carbon you have a complex structure of bonding atoms each carbon atom being bonded to four other carbon atoms (it has one of the highest melting points). For the metals you have a fairly loose bond between the atoms BUT some of the atoms are very ‘heavy’ and as melting any element means giving it energy and making the atoms move apart … the more energy you have to supply… the higher the melting point. (see my little story on a previous post).

So like you suggested in your question it is a complex situation, with lots of different factors affecting the temperature at which an element melts and maybe density is part of that…. (revised 24/07/16). You can ‘Leave a Reply’ or ask another question if you want further thoughts.

Fizzy drinks – A question from Nicholas (11)

Nicholas asked a question about his fizzy drink – “When you open a can of fizzy pop, what keeps the bubbles in the liquid? Why does it go flat slowly and not all at once, as soon as you open the can?” I asked my friends about this.

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The experiment involved slowly warming a saucepan of water. Long before it boiled lots of bubbles appeared. These were not steam bubbles but bubbles of air and they were slowly coming out of the water. There were no bubbles before I started heating the water. So where were they? Where were they hidden in the water? You might not believe it, but in water and other liquids, there is quite a lot of space for the air to hide itself. Your fizzy drink had quite a lot of space to hide the gas particles that they put in fizzy drinks (carbon dioxide).

Let me tell you about how I devised an activity to explain how this space came about in solids, liquids and gases.

Imagine you are with a group of people and you are asked to imagine that each of you is a particle of a solid – let’s say ice. Because you are a solid you will not be moving (you might be vibrating slightly). You will probably be part of a lattice of non moving particles. They were non-moving because it was ‘cold’ and  they had been asked to put their hand on to a shoulder of the person next to them.  I then told them that things were getting hotter (getting hotter, means giving them more energy) and that the firm bonds were going to break BUT they still had to remain in some loose contact with each other. As it got hotter they were to move more quickly around the room but they still had to be touching somebody else all the time. It was just a touch, maybe one hand touching another, no holding and they could  move from person to person but always be in a situation where they were touching somebody. They were no longer a solid they were a liquid. I then asked them to STOP and look at the space they had created …..space for air bubbles, and fizzy drink bubbles, space for other solids to hide in. (revised 24/7/2016)

What do you think happens when things get even hotter and everyone  is moving a lot faster? What will the particles become?

Sorry for the long explanation. I hoped it helps in your own understanding.

Two questions on electrocution and why does my phone get warm?

…. a couple of interesting questions. Which I will answer.

Electrocution is the term used to describe death from an electric current.

If you are going to die from an electric current it has to have certain properties. The voltage (or push) of the current must be high enough and the amperage (strength of the current) must be high enough. The electric current must also travel through the body in such a way that it passes through the heart or brain because it is those two organs that are most easily damaged by electricity (they both operate using electrical signals produced by the body). Electricity also has to have a pathway to the ground so if your feet are covered with an insulating material it might burn you (at point of contact) but is unlikely to kill you. To electrocute you the voltage could be as low as 40 volts and the current 500mA. Remember a battery can only produce a push of 1.5 volts and provide a current of 2000mA so even though the current is high the push is very low.

Mains electricity has a push of 250volts  and can provide a current of 13,000mA so it is very, very dangerous. Never, never, play with mains electricity. 

Warm telephones are caused by your working battery. Your battery is pumping electricity around your phones circuits. That electricity is lighting up the screen, and converting your voice into electrical signals, and converting the electrical signals of the person you are talking to into sound energy and sending the signals. It’s doing a lot of work. You get hot when you are working and try to cool down, the battery gets hot and tries to loose that heat by warming up your phone.

I hope these comments answer your questions.