“If all living things were in one food chain, what would be at the top?” asks Chelsea and Ashli (10)

Thanks team. I found a nice little revision site on food chains that you might like to try, find it at Food Chain Game.

Now to your question. Firstly it might be a little difficult putting all living things into one food chain. Secondly do you think it would be humans?  Ecologists (They are scientists who specialise in studying the living environment) rank species by their diets using a metric*  called the trophic level scale. Plants, which produce their own food, are given a rank of 1. Herbivores, which eat only plants, are ranked 2. The fiercest of meat-loving predators, such as killer whales, are rated at 5.5. Humans are rated at 2.5 which is the same level as a pig.

If you want to make a comment please use the box below or you could ask another question.

* metric as a noun means a standard scale of measurement so you could call a temperature scale a metric or any other standard scale of measurement a metric.

(updated 13/9/17 -changed metric to measurement)
(updated 15/9/17 – ‘measurement’ back to ‘metric’ after realising it was the correct word in the context in which it was presented, added addendum explaining it’s use as a noun)

“Why do volcanoes erupt?” asks Silas and Zakk (10)

 

Thank you Silas and Zakk for your question. My team are correct it’s all about pressure. All volcanoes have a thin ‘lid’ of solid rock which which is solidified magma. Underneath the lid is lots of molten magma which is heated by the Earth’s central core.

Things can happen to this magma. Some of it could cool, and solidify. You could also get convection currents like you do in any hot liquid. These can increase the pressure (push) on the volcano lid, break it and the pressure is released like the liquid in a bottle of fizzy drink.

Want to make a comment, please make it in the box below. Not sure about something …ask another question.

(revised 13/9/17  Magna misspelling and added support text)

Alice, Daisy, Eliza (10) asked “What chemical makes objects glow in the dark?”

Thanks team. I think we will start by looking at the meaning of the words that end in the term ‘escence’.

Fluorescence is the the almost instantaneous emission of light by a chemical that has absorbed light or some other form of energy and  then re-emits it.
Chemiluminescence is used to describe the production of light from a chemical reaction.
Bioluminescence is used to describe the production of light from a living organism. It is a form of chemiluminescence as it is chemicals within the organism’s body that produce the light.
Incandescence is the emission of light from a hot body. A heated piece of iron will glow.
Phosphorescence is the slow emission of light from a compound that has absorbed some energy, in some form…might be radioactive energy.

Note all of them involve , at one time gaining energy and then re-emitting it or chemicals moving from one state to another where the final state is of lower energy.(If you want to find out a little bit more on energy go to this Science Master Special)

If you have access to a low intensity UV torch ( check with an adult) you can look at at the compound Quinine for an example of fluorescence. Quinine is a compound in Tonic Water. In a dark room shine the torch (a UV torch produces BLACK light) on the bottle of tonic water and watch what happens. You can then make some ice lollies using the tonic water and again see if they are fluorescent.

Thanks for the question. If you want to make a comment feel free to do so in the box below…or maybe…you have a further question?

(Revised 13/9/17 – added energy link)

Liam (10) asks “Why does electricity go around a circuit?”

 

Thanks for that team , a very informative introduction. It’s usually the furthest electron that is involved in moving the electrical energy around the circuit.

I have tried to create a small animation to show how this might happen. The ‘pipes’ are the copper metal wire. the dots are the outermost electron attached to the numerous copper atoms. The battery is the ‘motor’ that makes the electrons move. To find out a bit more about how the battery work have a quick look at Sadies question.

Electrons are negatively charged particles so the negative terminal of the battery is ‘pushing’ the electrons while the positive terminal of the battery  is ‘pulling’ the electrons SO when the switch is closed all the electrons in the circuit start moving together.

Who do you think discovered that opposite charges attract and negative charges repel?

Now what about the filament in the bulb. Any idea why that starts producing light? Any thoughts on both these questions, let me know in the ‘Leave a Reply ‘ box.

 

 

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 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.

Science Master Special – Energy

Thanks team. I would like to add a few things.

Firstly the list of different types of energy is not complete. If you can think of some more then ‘Leave a reply’ in the box below.

Secondly it is interesting how the energy conversions can take place. For example a microphone converts sound energy into electrical energy and a loudspeaker does the reverse process, it converts electrical energy into sound energy. Can you think of other examples?

Any reader can leave a Comment in the Leave a Reply box below

Mattheiu (Yr 4) asked “If sound can’t travel through vacuums, why are they so loud?”

 

This is an excellent question. We are told that sound travels through the air to us by the vibrations of the air molecules between speaker and listener. But how does is get to us from a very distant speaker? Or through a vacuum? The magic formula is that one form of energy can be converted to another form of energy, as my team have explained.

If we can convert one form of energy to another then why not convert sound, which is moving air and therefore kinetic energy (the energy of movement) to electrical energy that can be passed down a wire or through a vacuum as an electromagnetic wave to a listener a long way away. When it is received the reverse conversion process can take place where the electrical energy can be converted back to kinetic energy, via electromagnetics and loudspeakers and not forget ears and brain.  Then by controlling the input to the conversion process we can control the loudness. Magic but real.

See my Science Master Special on Energy

Any reader can ask another question or leave a Comment in the Leave a Reply box below