Diffusing Particles

particles of perfume diffuse through the air

Diffusion in Gases

Patty wears a lot of perfume. As her body heat warms up the perfume small particles leave her skin and bounce around with the gas particles that make up the air.

The perfume particles behave in the same way as a gas: they are constantly moving. Near Patty the perfume particles are more concentrated (there are more of them) but the particles soon diffuse away from her and become less concentrated (there are less of them).

Remember, Patty would have put liquid perfume onto her skin - but her body heat will cause the the perfume to change state to form a gas ... which is what you smell.

Now answer these questions ...

  1. Is the perfume Patty puts on a liquid or a gas ?
  2. Patty's body heat turns the liquid perfume to what ?
  3. What other gas particles are around Patty ?
  4. The perfume particles are constantly doing what ?
  5. Are the perfume particles near Patty more or less concentrated ?
  6. Are the perfume particles away from Patty more or less diffuse ?
  7. What sort of energy does the perfume need to change into a gas ?
  8. In what state (solid, liquid or gas) can you smell the perfume ?

You scored out of 8 on that test


Diffusion in Liquids

When you put some milk in a cup of coffee the two liquids don't stay separate - they mix together to form a light brown liquid

The particles of milk and the particles of coffee are both constantly moving around and bump into each other all the time. As they move about the milk particles start to travel around the coffee cup and the coffee particles do the same.

The hotter the coffee is the quicker the particles will mix together - this is because the hotter particles will have more energy and will move around more than cooler ones.

 

... and now these questions

  1. Will coffee and milk mix or stay seperate ?
  2. Is the coffee we drink solid, liquid or gas ?
  3. What are the coffee and milk particles constantly doing ?
  4. Will the milk particles stay in one place ?
  5. Will the coffee particles stay in one place ?
  6. If you give milk particles energy do they move more or less ?
  7. What sort of energy do you normally give coffee particles ?
  8. Will hot coffee diffuse into the milk quickly or slowly ?

You scored out of 8 on that test