Ella (10) asks “Was there ever any life form on Venus?”

Many thanks for the question Ella. At the present time there is no evidence that there has been any form of life on the planet Venus. Venus is quite close to the Sun, it is the second planet. Because of it’s closeness to the Sun it is a very hot planet.

It would be brilliant if we did find evidence of life on the other planets of our solar system. It would be evidence that at one time life on Earth was not alone in our Universe. If that was the case we could assume that life could exist on other planets in our Universe.

The planet that is closest to the Earth is Mars. At one stage during its existence Mars had a lot of water on its surface. As life on our Earth originated in it’s oceans any life on Mars might have started in its oceans.

I’ll let my friends continue the conversation.

There are plans to build a new Space Station that will allow humans to go to Mars. Meanwhile there are several mechanical ‘rover’ devices on the surface of Mars which at this very moment are looking for evidence wether life, did once, exist on Mars.

Is slime a solid or a liquid? asks Taya (11)

In development.

Hello Taya, many thanks for your question.  Slime is a fascinating substance and the best way of producing it is to mix a substance called Borax, with a substance like PVA with some water. There are other ways to do it but this is the traditional way. Is slime a liquid or solid?  How do we measure how ‘liquid’ something is. We use a measure of the way a liquid pours, or if you drop something (a small metal ball) into it …how quickly it falls through it. This property of liquids is called it’s viscosity. Like most scales of measurement there are usually two extremes  and something in the middle can have a little bit of both of the properties of a solid and a liquid – the slimes.

The Viscosity Scale was established by Newton in (would you believe it 1770 -almost 250 years ago). Slimes are registered as a Non-Newtonian fluids .

Why Borax and PVA? PVA is a substance called a polymer. A polymer is a long molecular particle of repeating units. Polymers usually quite happily slide over each other (not very viscous). Add borax and it’s molecules attach themselves to the PVA polymers and stop the easy sliding. Thus a slime is produced.

Uncertain about things in this answer. Please ask more. You can also look at this previous answer to a similar question.

If pressure on a gas is increased what will happen inter-particle force?” asks Prince (13)

Prince.  An initial answer.

You have to think of how you are going to increase the pressure of a gas.

I can think of two methods …..imagine the gas in a Coke tin. The gas particles are rapidly moving around, bouncing of each other and the sides of the container. We can increase the pressure by

(1) decreasing the volume of the coke can ….the particles therefore will hit the sides more often (increasing pressure) or (2) increasing the amount of gas in the can which again increases the number of gas particles that hit the side of the can, again increasing pressure.

In both these cases the intermolecular forces are quite small. Most gas particles are fairly inert , they have intermolecular forces but they are slight. Water H2O and NH3; (ammonia) are probably exceptional.

HOWEVER as you increase the pressure further the gas molecules have less room to move and they get closer to each other …the intermolecular forces increase UNTIL they are so strong (because there are so many molecules in the small space) that the gas becomes a LIQUID. This is helped if you reduce the temperature at the same time (molecular movement is temperature dependant).

 

 

 

 

Science Master

“Why does soft serve ice cream increase in volume in a milkshake as it’s melting?” asked Tim (13)

Thanks for your comments team. I’m afraid you are wrong. My research suggests that Soft Serve has less fat than ordinary Ice Cream. The real difference is the amount of air in the ice cream and the temperature at which it is stored. In my view it is the amount of air that is crucial.  When Soft Served is warmed I would suggest that the air in the fat which makes up the ice cream makes the ice cream expand to a greater extent than the ordinary ice cream.

You could try a little experiment to confirm this. Take two equal samples of ice cream (soft serve and ordinary) of the same weight (use kitchen scales). Let them warm up. Allow the ordinary ice cream to reach the same temperature as the soft serve (ordinary ice cream is usually kept at a lower temperature than soft serve). Make sure that the two samples are in the same kinds of containers. Do they expand to the same degree?

What do you think the role of the air is in this process?

I hope that this gives you a clue to any differences that you see.

Tiago (?) asked “Why are beach sands so different in colour and size?”

I asked my friends about this but they were more interested in investigating sandcastles than trying to answer the question.

It most certainly is something to do with the water. Water wet’s most things.There are some things that water doesn’t wet. Things which are wetted by water are called hydrophilic while those that are not wetted by water are called hydrophobic.

Sand is hydrophilic so water can act as a sort of glue between sand particles, holding them together. It’s not a very strong ‘glue’ but it is enough to stop the sand particles falling apart in the sand castle. For more on this look at this previous question. Some scientist have done some research and found that you need between 1% of the mixture to be water to keep the sand together. T

There is, however, the small problem of the type of sand. There are lots of different types of sand. Sand comes from broken rocks and animal skeletons. Different rocks and skeletons change the colour of the sand. The most common sand is from quartz rock (SiO2) 

Black sand comes from eroded volcanic material such as lava, basalt rocks, and other coloured rocks and minerals, white sand was once the skeleton of animals, shells or coral reefs.

Sand is formed by the action of the sea on the rocks, constantly moving the rocks and breaking them. It is thought that the flatter the beach the smaller the particles of sand are. For steep beaches the sand particles are larger. It is something to do with wave motion.

“How, where or when we’re magnets found or made?” asks Sam (11)

Thanks for the question Sam. Magnets and magnetism was first discovered about  9000 years ago. A long time ago. It was found in rocks and called ‘lodestone’. Lodestone is a naturally occurring compound of iron. It is thought that it was magnetised by lightning strikes.

We will make our own magnets by using a slightly weaker form of electricity.  Here are my team.

Firstly let us try to make a magnet (without using lightning)

You will need a battery and a length of wire and some paperclips. The a collection of nails. Try and find as many different nails as you can. Wrap the wire around the nail and sellotape the bare wire ends to the terminals of the battery. See the diagram below. See how many paperclips you can pick up? Are some nails better than others?

DO NOT USE MAINS ELECTRICITY. IT IS VERY DANGEROUS. 

You might have found out that only certain metals can be made into magnets. These metals are called ferromagnetic metals.

Included in this group are the metal iron and the alloys of iron with the metals cobalt, nickel.

It is thought that in these metals (including iron) have some electrons called ‘free electrons’ (not sure what an electron is, then go to Science Master Special – Atoms and Atomic Structure). It is these ‘free electrons’ that are involved in magnetism. In the alloys the  ‘free’ electrons align themselves with the magnetism of the external magnet, making a (for the alloys) a permanent magnet.

Look at the short video I have made below. In the ferromagnetic metal (iron alloy) crystal domains you will see free electrons. In the metal these will be moving freely. As they begin to interact with the external magnetic field, they begin to align themselves, making a permanent magnet.

Liam (10) asks “Why does warm air go up?”

 

Thanks team. You are quite right we have to start at the beginning to really understand why warm air goes up. Let’s start by looking at what is air?

Air is a mixture of small gas particles (called molecules) of nitrogen, oxygen, carbon dioxide and some other gases. The image below could be a picture of what it would look like, if you could see it. What do you notice about it?

The red molecules are the oxygen, the blue the nitrogen and the others water and carbon dioxide. Imagine them moving around (I am trying to make an animation). Because they are moving they have energy.

If we heat the air, we are giving the molecules in it more energy. This makes them move faster and they move further apart.

The ‘thicker’ cold air surrounding the warm air drops into the space under the warm air and doing so pushes up the warm air which rises.

You can see this happening in a beaker of heated water.

Viper Astra (9) asks “What makes earthquakes happen?”

Viper, to answer your question it might be useful if we go back to the beginning. By the beginning I mean 4.6 billion years ago when the planet was first formed. Then it was a ball of molten lava. (1 billion is 1,000,000,000 or one thousand, million)

Over the next billion years the planet cooled and bits of crust formed on its surface. We call these bits of crust tectonic plates (the word ‘tectonic’ comes from the ancient Greek word for ‘building’ ……the crust is ‘building a surface’). These bits of crust got bigger, sometimes sunk into the molten sea they were floating on, but slowly covered the Earth.

Because they floated, the ‘plates’ of crust would have constantly experienced the movement of the molten ‘sea’ below them, so they moved and bumped into each other, and they are still doing that today. It is the movement and the, bumping into each other that causes earthquakes.

Watch this short video. It explains the different types of earthquake that can occur.

Thanks for the question Viper. Not sure about something then ask another question.

What natural phenomenon made the Mariana Trench? asks Sabine (9)

The Mariana Trench ….. I have been thinking about this and I think, worked out a way of explaining the answer to your question.

Firstly

Our planet, the Earth, is an interesting planet. It has a solid surface (we call the crust) that surrounds a molten (liquid) inside, called the mantle. Like a boat on water the surface floats on the molten liquid interior. Look at the image below:

Many millions of years ago the planet was just a hot molten sphere. Slowly the crust began to form. It didn’t all form at the same time so it became a little like a cracked egg shell with each bit floating and moving on the molten mantle. These pieces were the tectonic plates. The image below shows you the present positions of the tectonic plates.

You might be able to see what tectonic plate you are living on.

These plates are constantly moving (very, very slowly). When they bump into each other they can cause lots of problems, like earthquakes. The Philippine Plate and the Pacific Plate bumped into each other many millions of years ago  and this made the Philippine Plate sink below the bigger Pacific Plate …. and the result the Mariana Trench. See the diagram below.

Where is the Mariana Trench?

I hope this makes sense Sabine. Feel free to ask another question.

Mason (7) asks “Why is water wet?”

Thanks team. Let us start with a investigation. Let us look at the way water interacts with different materials.

 

Let us now look at the properties of water drops. Firstly let me define ‘cohesion’ and ‘adhesion’. The term ‘hesion’ means  … to stick. Cohesion is is the attraction and sticking together of the same things while adhesion is the attraction and sticking together of different things.

Look at the image of the water drop below. Each water particle is attracted to the other water particles around it , this is cohesion. Now add a different surface and the water particles are attracted to that rather than each other, this is adhesion. When adhesion occurs we get the spreading of the water drop and wetting,  providing the adhesive forces are greater than the cohesive forces.

So what about your investigation? Is there any evidence of cohesion or adhesion?

Here is a thought. it has been suggested that water is ‘wet’ because you can feel it’s wetness.

Maybe another little experiment.

You could let me know by clicking on the ‘Reply’ box below.