# Cheyanne (11) asked “What is the total charge of 7 electrons”

Cheyanne

I am a little confused  by your question. I asked my team for an answer……and here it was

Firstly the electron is a very, very small particle, it has a radius of 0nly 2.8×1015 m.   It is very, very small. That is an unimaginable small size.  Associated with this very small particle is an actual , very small electrical charge of about  1.6x 1019 volt (V).

So in reality when you are talking about the total charge of seven electrons you are only talking about  7 x 1.6x 1019 volt (V).

Sorry for this answer. I think it complicates things …stick to what my team member says. In reality when you are talking about the charges on seven electrons as 7- you are talking about the total charge that about  7 x 1.6 x 1019 electrons will give you .

# Lachlan(12) asks “How does a trebuchet work?”

Lachlan – my first question is what is a trebuchet?

Simple answer …It’s a type of catapult.

Here is an image of  a very early trebuchet

Here is an image that may help your understanding and give you some clues on how the trebuchet works. When the mass 1 is released it begins to accelerate towards the ground. In doing so a force is applied to the beam pulling it down. That force is then applied, via the beam to the mass 2. What do you think will happen to Mass 2?

The support for the beam, the fulcrum, is in a particular position. Any thoughts on that? You could create a see-saw and investigate the application of forces when the fulcrum  changes position ……altering d1 and d2.

# What happens to your eyes when you die? asks Olivia (12)

You did suggest Olivia that the eyeball might explode when a person died.  This is very unlikely. Look at the eye image below and try to identify the muscles in the eye. they will be attached to the two things that are constantly changing in the eye.

There are muscles attached to the lens and the iris.

When you die, your muscles relax. This causes the iris muscle contracts when this happens the eye is said to dilate ….like the image below

This is probably what your eye would look like  when you are asleep. Thanks for the question.

# Ellie (12) asks “What are the damages of hurricanes?”

Great question Ellie. I was going to ask my team to tackle this, however for some reason the question was left unanswered so to apologize I think I will try to answer it myself.

How is a hurricane created?

Air is made up of tiny molecules. When molecules are heated, they move faster. As they move faster they become become spaced farther apart, which makes the air less dense – meaning that there are fewer molecules in a given volume. This also means that the air has a lower overall pressure – pressure is the push of the gas on it’s surroundings. In comparison, cold air is made of more tightly packed molecules, and so it is denser and has relatively higher pressure.

The warmer, lower pressure air begins to move upwards and therefore it creates space below it which is filled by the colder higher pressure air. The warmer air ‘floats’ on the colder air. It also carries with it water vapour – water that has evaporated and contains lots of energy. A wind begins to be created. The hotter the air near the surface of the sea, the lower the pressure and the faster the rise.

As this warm air gets higher it begins to cool and also the water vapour that would have risen with it begins to turn back to water. A cloud begins to form. The energy of the condensing water vapour is given to the cloud.

The cloud of colder air and water vapour begins to move in circles (because the Earth is rotating). It meets other storm clouds. The hurricane is forming and is being fed by the warm air close to the warm sea.

What are the damages of the hurricane?

The strong winds of a hurricane can push water up and onto land. This water can cause major flooding and damage to homes, cars, and boats. Heavy Rains – Hurricanes can cause heavy rains that flood places inland and away from the center of the storm.

This video will help explain the formation of the hurricane.

# “What is the Earth orbit speed?” asks Joselo (12)

Joselo I would be interested in why you asked this question.

It is about 108,000 km/h. That is very, very fast,  Think of a fast car..it would be going at about 100km/h. The orbit around the Sun takes 365 days and the distance travelled is 970 million kilometers. Quite big figures.

I would be interested to know why I don’t feel that I am travelling at such a speed?  Why doesn’t the Earth lose its atmosphere?

Feel free to ask another question.

# “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.

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)

# Lara (12) asked “Do plants have brains or nervous systems?”

Great question Lara.  No, plants do not have brains or a nervous system BUT they may have something similar.

The brain and the nervous system are defined by science as consisting of special cells called neurons which pass messages to the brain and the neurons in the brain then process these messages. Plants do not have neurons in their structure. So if a plant can feel, communicate and maybe solve problems it is achieved by something other than the brain.

Lots of scientists have/are looking at plants and their behaviours. There is good evidence that plants can communicate with each other, trees (and maybe other plants) even have their own internet. Not a conventional network but an internet of fungi. It has been discovered that the fungi ‘roots’ called mycelium (they are not really roots …they are the main part of the fungi, the thing we see is just the ‘fruit’) create a network of filaments in the soil stretching great distances and connect to other plants around them. Researchers  have found that trees communicate information on food, insects and other dangers to each other using this network..

Mycelium

There is a lot we do not know about plants.

A question. Suppose you had access to ten trees and a mycelium network. What experiment would you setup to test the ideas about the trees communicating  and helping each other.

Hope this helped. Need further help then please ask another question or make a comment.

Science Master

(Anyone reading this post who wants to ask a question or make a comment please feel free to do so)

Revised 9/9/17 Added  ‘A question.’ Last para.

# “How do you measure the distance to the Sun and stars?’ asked Julian (12)

Julian, quite a challenging question. I will only be trying to answer the first part – the Sun-Earth distance and the Earth-Stars distance.? Even then as my team suggests, I might be introducing mathematical terms that you have not met yet, but I have included links to other sources of help.

To answer the first question I recommend you read a Universe Today article   It is an excellent historical review of the problems that the early scientists had in determining the Earth-Sun distance. The answer finally came from observations of the movement of the planet Venus across the face of the Sun. In it the writer refers to a Nasa document that tries to explain the methods used. In present times the distance to the Sun is measured by ‘bouncing’ a radar pulse of of it.

Determining the distance to the other stars becomes possible once the Earth-Sun distance was known. It uses a technique called parallax.  I would like to illustrate this with a question which tackles a simpler problem. ‘How far is my finger away from my nose?’

Try this little experiment, put a finger in an upright position in front of your nose. Now close one eye and note the position of the finger. Close that eye and open the other one. The finger moves! Now suppose, with help, you could measure the amount of movement. You could end up with diagrams like those below. Did you make a note of the position of your finger relative to your nose? No – you can now see how you could work this out.

Now let’s do a little geometry and add an axis

We can then measure the angle of the apparent movement

You end with a right angled triangle ABC, knowing the angle x AND the distance between your eyes you should be able to do a bit of trigonometry using TAN x = opposite/adjacent (Tan x = AB/BC) and work out the distance of your finger from your face. For an introduction to trigonometry please look at this site.

Amazingly this is (in a crude way) the same process by which astronomers can measure the distance to the stars. Instead of using the distance between your eyes they use the orbit of the Earth. They look at a star and make a note of it’s position and then do the same thing 6 months later when the Earth is at the opposite side of the Sun. They therefore have AB (the distance between the Sun and the Earth and they have the angle through which the star has apparently moved.

This gives the route to determining the distance between the Earth and a Star.

(revised 14/05/17)

# “If I was sucked into a black hole what would make me die?” asked James (12)

It is thought that a ‘black hole’ is produced when a rather large star comes to the end of it’s life. It collapses in on itself and forms an object of incredibly concentrated matter. As ‘gravity’ is a property of the quantity of matter (see my answer to Ernie’s question) the collapse causes an immense increase in the gravity from the  smaller collapsed star.

It is unlikely that our Sun would end in this way as it is classified as a smallish star. It is likely to become something called a ‘Red Dwarf’ star.

The ‘black hole’ is explained by the fact that this concentration of gravity ‘pulls’ light into it, thus the ‘hole’.

Now if you were close to the collapsed star in your spaceship you would also be pulled into it and unfortunately be added to the mass of the collapsed star. Sorry, you will be crushed.

(slightly revised 20/4/2016)

# Akshita (12) asks “In a circuit of 5 light bulbs and 2 batteries why do all of the light bulbs come on at the same time when you switch the switch?”

Thank you team. You are right metals are much more important than the plastic coating. You could replace the plastic coating with paper or rubber or cloth BUT the metal has to be a metal. Why. It’s all to with things called electrons. Most elements

• An element is a group of atoms that all have the same number of protons (positively charged particles) in their nucleus. Oxygen is the most abundant element on the Earth, Iron is the most abundant metal element.

have electrons that are tightly held by the nucleus but metals are different. The outer electrons of metals are rather loosely held by the nucleus and are free to move around within the metal structure. So if we looked at a circuit which was not connected to a battery (switch is Off) and looked closely at a small section of the wire you would see something like this …

The little red dots depict the outermost electrons of the metal atoms (the element nuclei are the positive circles).  You have to imagine that the electrons are constantly moving around within the metal structure and probably keeping quite close to their parent atom.

Now close the switch.

The battery is now pushing the electrons around the wire (- to +). This push is a bit like a long chain being pushed or pulled. All the electrons in the wire experience the push simultaneously (like the links in the chain) so when the switch is closed all the lights in the circuit will experience the ‘push’ and the electrons in the vicinity of the bulb filament will give up some of the energy of the push to the filament which will be converted to heat energy and create a hot filament which is then partly converted to light energy.