Can we see gas?

Gases are everywhere, we cannot always see them but there are some we can definitely smell! Some gases are poisonous and don’t smell very good. This is why the sense of smell is important, to detect things in the air that we cannot see that might be causing us harm.


Characteristics of a gas

The tiny pieces or particles that make up a gas have a lot of space between them. This lets gases move around freely and adapt to their containers. If we put air (a gas) in a balloon it will fill up all the space, this doesn’t happen with solids. Knowing the difference between solids, liquids and gases helps us know the best materials to use in each case.

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The three phases of matter: solid, liquid and gas

Matter is what makes up everything we see and touch; it comes in three main states which are solid, liquid and gas. Things can transform from one state to another by changing temperature or pressure. When it’s very cold water can turn into ice and when it’s very hot water can turn into gas.

Solids - The particles in a solid are held together really closely, this stops them from moving. This is what makes solids so hard and stops them from flowing.

Liquids - The particles in a liquid are also held together closely but not as much as solids! They have more space between them and this is why they can flow.

Gases - The particles in a gas are very far apart so they are always dancing around and filling as much space as they can.

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Interesting facts about gases

  • Gases cannot always be seen or smelt but they are a huge part of our everyday life.
  • Take a deep breath in…you could do that thanks to gas filling your lungs.
  • Gas is also used to fill balloons and to make drinks fizzy. 
  • Gases can expand or shrink to almost any size.
  • Some gas particles move about so quickly they are faster than the speed of sound.
  • Fire is a mixture of hot gases.
  • The air we breathe is made up of different gases, it is approximately 78% nitrogen, 21% oxygen, 1% argon, and a couple of other gases as well.
  • Natural gases are lighter than air, they are also odourless. Energy companies add a rotten egg smell to the gas so that people will be able to smell it if it leaks.
  • Gases that are usually liquids at room temperature are called vapour.
  • Heat makes gas expand.
  • Perfume is a gas that can be smelled.