vacuum flask

living seeds

cotton wool

thermometer

dead seeds

What happens and why?

Flask A Flask B

Method

• The experiment was set up as follows.• In flask A seeds were boiled for 10 minutes,

allowed to cool and then soaked in disinfecting solution for 10 minutes.

• In flask B seeds were soaked in disinfecting solution.

• The flasks were left in the same place.• After two days the temperature inside the flasks

was recorded.

Results

Temperature Flask A (oC)

TemperatureFlask B (oC)

Day 1 24 24Day 2 23 29Day 3 23 33

Discussion

• 1. Why were the seeds in flask A boiled?• 2. Both sets of seeds were soaked in disinfectant.

Why is this necessary?• 3. How can you explain the difference in

temperature between the two flasks?• 4. Why was it necessary to use insulated

(vacuum) flasks for the experiment? • 5. What factors were controlled to ensure the

experiment was a fair test?