Include:

∙ A concise, testable hypothesis, explained by an introduction.

∙ Full experimental details including control of the experimental variables, and number of replicates.

∙ Risk assessment (scalds, cuts, electrocution, slipping, mercury in thermometers).

∙ A table for the collection of raw results.

∙ An outline of how the results will be processed (table 2 and graph) to determine whether the hypothesis should be accepted or rejected and an assessment of error (range, standard error or semi-interquartile range). A statistical test could be used, e.g. Mann-Whitney ‘u’ test to compare the significance of a difference between two groups of data (p = 0.05). See the statistics folder for this.

∙ Evaluation – discuss variability, trends, explanation involving conduction, convection and radiation, improved methods and further work.

## Null Hypothesis

Vessel size will not affect the rate of heat loss.

(For example, you could compare the rate of heat loss from 500 cm3 and 250cm3 conical flasks). You will need to be able to calculate the surface area and volume of the vessels (at least approximately). Both types of vessel will need to be plugged with cotton wool through which a thermometer can be placed. Six replicates of each data set allow the Mann-Whitney test to be done.

Variables include: volume; surface area; glass thickness and type; surface on which the flasks are standing (conduction); air movements; air temperature; starting temperature; type of bung in flask opening; method of temperature measurement and how close together the flasks are.

Use the Assessment Criteria Sheet to ensure that all points are adequately covered!