“When your car crashes why does a fire start?” asks Ruby (8)

Ruby, I hope this answers your question. If you have some other thoughts you can make them in the Leave a Reply box below or ask another question.

 

Sadie (8) asked “How do batteries work?”

Sadie, many thanks for your question. I asked my friends to help me…

 

Yes I remember doing that, it wasn’t easy but I did get the led to light up.

Let’s start with a possible definition of a battery – It’s a device that converts chemical energy into electrical energy. If you are uncertain about what I mean by energy then have a look at this site.  

Now why do we have two different metals? Inside the squeezed lemon is a lot of lemon juice. There is a chemical reaction between the metals and the lemon juice. Because the metals are different they react with the lemon juice in different ways. The different reactions give the copper nail a positive charge and the iron nail a negative charge.

Connecting the two nails together with a wire will give you a flow of electrons in the wire from the iron nail to the copper nail. This will continue until the chemical reaction inside the lemon reaches completion.

Your normal battery is like the lemon but obviously made of different materials. Look at the diagram below.

Sadie, I hope you have found this useful. If you or any other reader would like to make a comment please fill in the Leave a Reply box below. And if you are uncertain about bits of the explanation please ask another question.

Additional note …copper nails are difficult to get hold of so why not use a small piece of copper tubing. Also there is a small possibility that a battery was produced over 2500 years ago, see The Baghdad Battery. Ask your teacher about it. Or ask another question.

“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.

 

“Why do metals always feel cold when I touch them?” asks Chen (8)

My question is, are the metals colder or warmer than the things around them? We need to test this question. So how?

We need find out if other materials behave in the same way.  We therefore need to test it with other materials, for example, wood, plastic, china and glass.

To make the test fair (an important part of my experiment) we need to make sure that all of the materials are at the same temperature at the start of the experiment. We can test this by taping a thermometer to the materials, leaving it there for a period of time (maybe 5 minutes) before touching each of them. Do they feel hot or cold? Do they feel like they are at the same temperature that you are.

What did you find out? If the metal, or other material did feel colder, or warmer, than the others then why?  Let me know what you think by filling in the Reply box below and post your comment or ask another Question . Anybody can do this.

Ethan (8) asked “How can you hear things?”

 

Ethan. There are some other small experiments I would like you to try.

Find a ticking clock and a box that you can put it in.  Listen to the ticking with the lid on and the lid off. could you hear the ticking when the lid was on?  Now with the lid on get a cardboard tube (maybe one from a tube of kitchen roll) , put one end of the tube on the box lid and the other end over your ear. Listen. Is the sound of the ticking louder when you use the tube? Move your ear away from the tube. What happens to the ticking?

Ethan, lots of questions from me to you.  Maybe the experiments have created some more questions. Any reader can ask a question or leave a Comment in the Leave a Reply box below

Also see Clara’s question on sound.

“If I do a headstand will my brain get too much blood?” asks Susan (8)

Susan , I asked my friends about your question and this was their thoughts.

Thanks team, some interesting thoughts. Firstly let’s confirm that it is the heart that pumps the blood around our bodies. In a normal situation the heart is strong enough to pump the blood up to our head, so it might find it easier to pump the blood to our head when we are upside down. Any idea why? Think of gravity.

When you are doing a headstand the heart will not need to fight gravity to get the blood to your head, so it might find it a bit easier. It does however still need to get the blood to your feet (which are now above your heart) but it is strong enough to do this.

There might be some visible signs in the way the blood circulation changes. If blood has a little difficulty getting to the feet they might go a little pale. If the blood does not leave the head as quickly as usual, the face might go a little red. You might also get a change in the pulse rate if the heart has to work harder. These can all be tested with a healthy volunteer.

(edited 19/01/2017)

How strong is a thunderstorm? -asked Jessica (8)

thunderclouds

Many thanks for your comments team. Yes you are right, to create a thunderstorm you need a lot of warm water. It’s development goes by the following crude set of stages …

  • Lots of warm water evaporates (turns from a liquid state into a gaseous state.). Thunderstorms are therefore more common in the warmer regions of our planet.
  • The gaseous water is forced upwards by the warm sea. The warm sea warms the air close to it. This air expands and is therefore becomes ‘lighter’ and moves upwards carrying the water vapour (water vapour is the term used to describe gaseous water) with it.
  • As the gaseous water rises it gets colder (more distant from the warm sea) so it becomes water again (small drops of liquid water). A cloud begins to form.
  • The heat from the ocean continues to make the water and water vapour(clouds) rise.
  • It gets even colder and more of the water vapour turns back to water.
  • Some of the water droplets in the cloud turn into ice particles.
  • The ice particles separate some move to the top of the cloud others remain in the bottom.
  • This split causes an uneven distribution of electrical charge in the cloud.
  • The result is Lightning and Thunder.
  • Some of the frozen water falls away from the cloud. this causes all sorts of down draughts and strong winds are created.
  • Some of the ice does not melt as it falls through the air – this forms hailstones.

You could look at this question http://www.sciencemaster.co.uk/2016/11/18/elizabeth-9-asked-a-question-on-lightning/

 

Any questions, please leave them in the `Reply Box’

Jessica(8) asked several great questions about the Solar System

Jessica. I have asked my team to answer the information based questions. I will try to help you with the other questions.

Jessica asked about Dwarf planets, the temperature of the Sun, The Earth’s layers and the size of Jupiter. Here are the comments from my team.

solarsystem1solarsystem2

 

I was interested in your question about Venus having an opposite spin to that of Earth. Earth has (if you are above the North Pole) a Counter (Anti) Clockwise spin while Venus (if you are above Venus’s North Pole)has a Clockwise spin. Most of the other planets spin in the same direction as the Earth. Here is a little experiment…..

Pick up a pencil and holding it upright begin turning it in a clockwise direction,  now still turning the pencil, turn the pencil through 180 degrees. Which way is the pencil now rotating, clockwise or anti clockwise?  It is thought that close to the beginning of the Solar System a close encounter with another large object caused the axis of Venus to move through 180 degrees. Is that a theory or a hypothesis?

To your question about the position of Mercury – I have no idea why it is the nearest planet to the Sun. At the beginning of the Solar System you have the Sun surrounded by orbiting space dust. This dust slowly collects together and the planets begin to be formed. The closest ring of dust to the Sun formed the closest planet (Which we call Mercury).

“What is the earth made out of” – asks Ruby (8)

Ruby, many thanks for the question. Now let’s think about what it means. Does it mean the ‘earth’, like the soil that we have around us OR does it mean the ‘Earth’, the planet that we are living on. I say on my front page  that science is all about asking questions, but asking them is not always an easy task, so well done you. I shall get my friends to try and answer the ‘earth’ question and I shall then give you an answer to the ‘Earth’ question. We might even find something for you to do!

earth-or-earth

 

So maybe you could find out something about how easy it is to break a rock up? How about making a small collection of some rocks. They are quite easy to find at Garden Centres, or on walks in the country, or on a stony beaches. Collect some and then try to scratch them. Can some rocks scratch other rocks? If they can which is the hardest? try to draw a picture of your hardest rock. It is most likely that it will be the softest rock in your collection that you will find in your ‘earth’.

Now Ruby let us look at the ‘Earth’ and the wonderful structure that you are standing on. This is where your rocks have come from.

I have built this small animated picture to show you the amazing ‘inside’, structure of the Earth.

Alka asked – Where do puddles go to?

Many thanks for the great question Alka. I put it to my friends and as usual they came up with some interesting thoughts.

puddles2
Many thanks team. What we need to do is set up some experiments that might help us find a possible answer. If we had a bowl of water how would we protect it from insects, and other animals drinking from it?  How would we prevent leaks into the ground? How would you stop the Sun grabbing it?

This could lead to lots of different experiments.

Try making some small puddles in a some bowls. Keep one bowl in a cupboard and one on a window ledge for a couple of days. Put one bowl outside and another outside with a cover over it to stop animals getting to it.  Maybe leave them both in a shady spot so they cannot see the Sun. Create a puddle on some solid ground and another on some ground with some plastic between the puddle and the ground.  These are some possible investigations that you could carry out to find an answer to your question.

Fair testing is an important part of  investigations, it is difficult but amazingly rewarding. How do you make all those tests fair? does leaving them all for the same length of time make it fair? What about the amount of water? Would that influence the fairness of the test?

It maybe that for all real puddles a bit of everything happens.

Let us know your thoughts/answers by using the ‘Leave a Reply‘ section below. Unsure about something..then ‘Ask a Question‘.

Here is a little video of somebody else with the same problem. It uses a word that you might not understand ‘evaporation’. If you want help Ask a Question.