Billie and Zali (10) asked “How does the activator form slime?”

Sorry team.  You have provided some good background material. The important thing about making SLIME is that all the ingredients in it’s making (The Activator, the PVA and water)  have something in common, lots of O-H chemical bonds. It is these that make the SLIME a reality. Look at the diagram of a PVA molecule and count the number of O-H bonds. Remember this is a Polymer so the image below is just one bit of a much bigger molecule of PVA.

So what is it about the O-H bonds that make them so important.

Look at the following short video ….



It’s all due to Hydrogen bonding. Everything is attracted to everything else by the Hydrogen bond environment that is introduced when you put all of the ingredients together. SLIME becomes the reality.

Think about it. Make a comment or if you don’t understand a complicated bit then please- Ask another Question

(revised 13/9/17 – PVA is polyvinyl acetate not polyvinyl alcohol, Diagram of PVA included and last paragraph revised)

“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)

Elizabeth (9) asked “How doesn’t stainless steel stain?”

Elizabeth I would like you try an experiment. Gather together some different nails. If you can, find a stainless steel nail, steel nail, iron nail and as many different nails that you can. Try and get two of each. Find two jam jars and put one set of clean nails in one jar and the other set of clean nails into the other jar. Why do I suggest cleaning the nails?

Fill the first jar with tap water and the second with water that has been boiled and cooled. Cover both with cling film and leave for about 7 days. What happens ?????

Relook at what you did at the start. What did  you see in the tap water that you added? How did this compare to the boiled water? What did you see when you boiled the water?

Most of the stains on metals are caused by interactions with water and oxygen.

When steel and iron are attacked on their surface by the oxygen from the water you get  things called oxides created as the oxygen (a very reactive gas) reacts with the metals surface. For most metals the compound (oxide) that is formed is fairly ‘soft’ and is washed away creating new sites for oxygen attack. With stainless steel it is the chromium in the stainless steel that reacts with the oxygen creating an invisible layer of Chromium Oxide and this is such a hard substance that no other substance can stain the steel.

If you rub the stainless steel implement hard with a scraper you might get rid of the strong oxide and create a stain by attacking the surface of the steel with another substance. Try it (with permission).

Elizabeth and others, quite a detailed answer. If you want to ask further questions please ask.

Donna (7) asks “Where do clouds come from?”

Donna, many thanks for the question. Before trying to answer it I thought I would ask my team a question.

Donna, what do you think about the puddles question? Think about how you would answer it and then go to my answer to a previous question.

Now to your question. Firstly I have created a little animation to show how the puddle disappear. You have to imagine that the shapes are water particles (molecules is the proper word). In the puddle they are all moving around. Most of them like being with the other particles BUT some are just moving around a little bit too fast and manage to escape from the puddle. When the Sun begins to warm the puddle it makes more water particles move around faster and more escape. This goes on until the puddle disappears.


The water particles are very small and are are lifted by the air up into the sky. High above the ground the air is quite cold so the water particles ‘slow down’. When they are moving ever so slowly if they meet another water particle they join up with each other and form droplets of water. This is how a cloud begins to form.

At home look at the steam from a kettle, BE VERY CAREFUL AND CONSULT AN ADULT.  At the exit of the kettle spout you can see nothing, BUT just above this the hot water particles begin to cool down and slow down and reform clouds of water.

(revised 21/4/17)

“Why can heavy things float”? ask Aiden (10)


Aiden, great question,a difficult answer. I hope that you have investigated which things float and which things sink. You should be able to look around you and say ‘That floats’ and ‘That sinks”. Think about this – when something sinks it seems to be breaking the surface of the water. What is it breaking? I pass this back to my team.

The attractive forces between water molecules are called intermolecular forces. Look at this post to find out more.  When the much bigger metal boat hits the water, because of it’s design (spread out) there are lots more water particles that push on the boat and keep it floating.  Squash the boat up into a small lump of metal  and drop it into the water. What do you think will happen? Let me know what you think by leaving a comment in the ‘Leave a Reply’ box below.



A question “How does the world work”

Some time ago a well known scientist (James Lovelock) suggested that the Earth (our planet) was special. He claimed that the Earth itself was a living thing and had control over its environment. He gave the Earth the name Gaia (a Greek name for the goddess of the Earth) and suggested that the planet’s objective was to support life on it, at all cost.

It has been argued, by those who support this idea, that there is a lot of evidence from investigating the Earth’s history over the last 3 billion years, that suggest the idea is valid. Below are some of those arguments. What do you think?

The Gaia idea is something called an hypothesis (an idea). It has yet to be proven. If proven it can then be called a theory.


“When you shake a fizzy drink that is full when you open it and it explodes?” asked Ruby (8)

When you open the bottle you should hear a gentle fizz. When you pour the drink into a glass you get a bigger fizz and lots of bubbles. If you had ice in the glass you would get even more bubbles. This is because the surface of the glass and the ice cubes are full of little gullies and points. The gas bubbles that were hidden in the liquid attach themselves to the gullies and start to get bigger, (bubbles grow by being joined by other bubbles) and bigger and then when they are big enough, because they are lighter than the liquid, they rise to the surface.

Here is a little experiment for you to try —put the ice cube in your mouth and get your tongue to smooth it, for a few minutes. Think about what I have said and try and predict what the outcome will be when you pour a new bottle of drink over it. Now add the carbonated drink and test your prediction.

Now what happens if you shake the bottle before opening it. This is where you get the explosion!  Here is my possible explanation……. look at the bottle of drink.

(1) There is an empty space at the top of the bottle. It’s not empty, it is full of Carbon Dioxide gas.

(2) When you shake the bottle that gas mixes with the liquid and because bubbles attract other bubbles the gas in the liquid becomes more bubbly.

(3) The bubbles that were hidden in the liquid join the new shaken bubbles. Undo the top and these new bigger bubbles all escape at the same time pushing the liquid before it – the  explosion.

Look at this previous post.


Sadie (8) asked “How do touch screens like iPods work?”

Sadie, I and my team  have already answered this question. See this answer to Rainnie.

To check on whether a question has already been asked go to the right hand column there is a SEARCH THE SITE  box. Type a keyword , like ‘Touch’ into the box and then click enter on your computer. It will lead you to the answer I have connected you to .

Sadie, thanks for the question. It shows how important it is to Search First.

If  you are uncertain about some bits of the answer then please feel free to Ask Another question.

“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.


“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.