EducationPhase 3Portion size experiments

Introduction

Three experiments are available, designed to help you think about portion size and the impact it has on energy intake.

As well as this PowerPoint, there are pupil worksheets where you can record your answers. You may also need graph paper to display some of your experiment results.

Experiment 1: Investigating the difference between estimated and weighed portions of breakfast cereal

Equipment needed: •Weighing scales;•Breakfast cereal (same breakfast cereal for all class members);•Bowl (same size for all class members);

Method

Estimate how much the portion size of breakfast cereal you would usually serve yourself weighs. Record on your worksheet.

Place the bowl on the scales and set to zero. Pour into a bowl the portion of cereal you would usually serve yourself. Record the portion size weighed on your worksheet. Ask five members of the class to measure their own portion of cereal. Complete the questions on the worksheet.

Experiment 2: Investigating the difference between estimatedand weighed portion sizes of different breakfast cereal types

Equipment needed: •Weighing scales;•Breakfast cereal (three different types, e.g. bran flakes, rice puffs, granola, muesli, cornflakes, malt wheat, clusters);•Bowl (same size for all class members).

Method Choose three different cereals to measure. Estimate how much the portion size of each breakfast cereal you would usually serve yourself weighs. Record your estimated portion sizes on the worksheet. Place the bowl on the scale and set to zero (0g).Pour into the bowl the portion of cereal you would usually serve yourself. Record the measured portion sizes on the worksheet. Ask five other members of your class to estimate and then weigh their portion size for each of the cereals. Record the portion sizes in the table. Complete the questions on the worksheet.

Experiment 3: Investigating the impact of bowl size on weighed portion size of breakfast cereal

Equipment needed: •Weighing scales;•Cereal (same cereal for all class members);•Bowl (three different sizes – e.g small, medium, large).

Method

Place a small bowl on the scale and set to zero (0g). Measure into the small bowl the portion of breakfast cereal you would usually serve yourself. Repeat the process with a medium and large bowl. Ask five other people in the class to carry out this experiment. Record the answers in the table on the worksheet. Complete the questions on the worksheet.

What factors may affect portion size? Use the images below to help prompt you.

How can increasing our portion size affect the energy balance diagram shown below?

Energy in (food and

drink)

Energy out (activity)