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Investigating the Rate of Evaporation

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Fig 1: Dropper bottles are recommended for this practical
Fig 1


Pupils investigate which factors affect the rate of evaporation.


Evaporation happens when a liquid turns into a vapour without necessarily reaching a boiling point. This investigation allows pupils to see what factors affect the rate of evaporation of propanone.

Equipment required (per set):

  • Stopclock
  • Microscope slide
  • Propanone (highly flammable)
  • Pipettes or droppers
  • Used matchstick

Pupils investigate what factors increase or aid evaporation of the propanone. A drop of propanone is placed on the microscope slide and one of a number of conditions is applied while the pupil measures the time it takes. Results are taken and pupils use the data to decide which method is more effective.

Conditions may include:

  • Spread the propanol over the slide with a used matchstick
  • Blow warm air over the surface
  • Fan cool air over the surface
  • Warm the slide (in hands)
  • Cool the slide (pre cool the slide in a fridge or on ice)

The above conditions can be applied singly or combined for more variation.


 Highly flammablePropanol is highly flammable.

Ensure there are no ignition sources nearby.

Wear eye protection.

The contents of this page are for information only. Please refer to CLEAPSS or ASE safety advice and/or publications before undertaking any preparation, practical experiment or using any equipment featured on this site or any other.