04. The composition of air

Why is the atmosphere made up of so few gases?

Outcomes:

- Be able to state which gases are in the atmosphere and what their relative percentages are.

- Be able to experimentally test some of these figures.

Activity: Which gases make up which percentages of the Earth's atmosphere?

Activity: Checking the percentage of oxygen.

If we repeat the experiment, can we:

• 1. Explain what is happening and why?

  2. Use this experiment to approximately confirm the percentage of oxygen in air?

Equipment:

• • tea light (candle)

  • petri dish

  • water with blue food colouring

  • 100 cm³ beaker

  • 100 cm³ measuring cylinder

  • 250 cm³ measuring cylinder

Method:

Come up with a plan, test it and then post your results in the Google Sheet.

Results:

Extension:

Answer the questions on Oxygen data analysis

Next lesson: Oxygen and oxides