Appendix 2: Teacher notes - outputs of the lesson

Task 1

All students will have the same choice of foods. The initial weight of each type of food will be slightly different for each student (+ 0.02 g).

The initial and final weight include the mass of the crucible; students are only interested in the difference between these values:

Mass of food burned = Initial weight – Final weight

The initial temperature of the water is 21.1 + 0.2^oC

The table below summarises expected experimental data of mass of food burned and increases of water temperature:

Food	Mass burned / g	ΔT / oC
Coconut peanuts	0.81	3.8
Plantain chips	0.65	2.7
Puff Puff	1.15	2.9
Fufu	1.48	3.2
Millet Porridge	0.81	0.6

Students should supply data from at least two replicates.

Due to lab safety issues and/or deviations from the procedure that could introduce experimental error, there are some alerts appearing in the application and advising students in various situations (e.g. opening the oxygen source before starting the water-jet pump, stirring the water before taking a temperature reading).

Task 2

The table below gives the expected set of experimental data for energy in food and the actual values on food labelling:

Food	Energy transferred   / kJ (exp data)	Energy per 100 g  / kJ (exp data)	Energy per 100 g / kcal   (exp data)	Energy per 100 g / kcal (food label data)
Coconut peanuts	16.1	1988	475	553
Plantain chips	11.3	1743	416	517
Puff Puff	12.1	1054	252	361
Fufu	13.4	904	216	319
Millet Porridge	2.5	310	74	37

Experimental data would be more reliable if greater masses of food were burnt (reducing uncertainty in weight and temperature measurements). Heat loss is also contributing to the error in this experiment.

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