Remember, as a member of the Science Bus Club you can ‘Ask Albert’ a question about any of the topics. So if you’re not already a member join today!!
Some Useful Words For You To Remember
Reversible - This is where a substance can change from one form to another. Think of water. It can go from solid to liquid to gas and back again. Think what reversing means. It means going backwords. That’s’ how I remember it/ Can you think of another way to think of it.?
Irreversible - That means exactly the opposite of reversible. Did you ever see a bonfire? Well, fire or burning is an example of an irreversible reaction. Once you light a piece of paper and it burns you can’t make it back into a piece of paper.
Soluble - That means a substance dissolves in a liquid. Try this , fill a glass with water and add two teaspoons of salt. Stir it. It dissolves in the water.
Insoluble - That means exactly the opposite of soluble.
Filtration And Evaporation
An insoluble substance like sand in water can be separated by filtration. In other words you put up a barrier that will allow only one of the substances to pass through. Did you ever see you Mum or Dad using a kind of sieve to drain off the water in your dinner vegetables. Well that’s filtration.
You can try it with sand. Here is what you do.
Get some sand and put it in a cup. Now pour in some water.- To separate the liquid and solid get an empty cup and put a tea towel over it.
- Now slowly pour the mixture into the towel.
- The liquid will go into empty glass and the sand will remain in the towel.
Cool, eh?
Evaporaton is when a liquid in an open space loses some of its molecules to the air. The energy in the water molecules allow some to escape. Did you know that in some countries they trap seawater and let the water evaporate off, leaving just the salt and other important materials?
Making New Materials
Look around you…everything you see is made from joining materials together until they make something new. If you mix sand cement and water you get concrete. This is an example of an irreversible reaction.
Did you make Carbon Dioxide in class? If not here is what you do.
- Take some baking soda ( bicarbonate of soda) and put it in a plastic bottle.
- Now add some vinegar and quickly place a balloon over the neck of the bottle. Get an adult to help you if you struggle with this.
- A gas will be released and it will inflate the balloon. That’s carbon dioxide.
- Tie off the balloon. YOU JUST MADE A NEW MATERIAL.
Now look around again and see that everything you see has been made (reactions) from other materials.
Heating And Cooling Materials
Heating and cooling can cause things to change too.
Next time you see your parents fry an egg observe that it turns out completely different than it started. The heat has changes the egg in a reaction that cannot be reversed. The important thing to remember is that the egg hasn’t been burning : its just being heated. BURNING is a different reaction.
Cooling can change things too. Think of water, ice and steam.
Burning
When you burn something it changes irreversibly. For something to burn it needs Oxygen. Much of the products produced with burning are dangerous. Did you ever accidentally breath in smoke from a fire. Smoke is made up of very small pearticles of matter and some gases. Yuk!
Remember, as a member of the Science Bus Club you can ‘Ask Albert’ a question about any of the topics. So if you’re not already a member join today!!
