8 ORGANISMS REQUIRE A SUPPLY OF ENERGY AND MATERIALS FOR WHICH THEY OFTEN DEPEND ON, OR COMPETE WITH, OTHER ORGANISMS

Task 9

WORKSHEET

Materials and tools for a working group:

  • empty packages of various food and beverages (see worksheet)

This activity is aimed at examining the energy value of food. The aim is not to explain the individual nutrients to the pupils, but to make them aware that each food provides us with a certain amount of energy.

At the beginning, the teacher asks pupils where one takes energy. The teacher then discusses topic of food with the pupils while paying appropriate attention to question why it is important to us. He writes the pupils‘ answers on a blackboard. Subsequently, the teacher will show the pupils pictures of various foods (waffles, cheese, oatmeal, nuts, chocolate, etc.). The task of the pupils will be to think about which food will give us the most energy. They write down their predictions and then discuss them together.

After the discussion, the teacher asks the pupils how they could find out how much energy we get from each food. Pupils can consult their group predictions and then suggest (write / draw) how they can verify their predictions.

Pupils present their proposals and, if possible, implement them. The teacher should ensure that pupils‘ suggestions determine exactly what they want to find out, and it has to be appropriately objective measurement. If the pupils have a problem with this step, the teacher will distribute the products to them (it is sufficient if they give them empty packaging). He will invite them to properly inspect the packaging and try again to propose a way to verify their predictions. He draws the pupils´ attention to a table on the packaging that provides nutritional information.

Each table of this kind contains data on macronutrients and vitamin content. In this activity, they focus only on the energy value of the food, which is indicated on the packaging in kJ and kcal. It is up to the teacher to determine the value (kcal is recommended). The pupils will note that this value is 100 g of food. Before determining the energy value of these foods, it is advisable for pupils to weigh 100 g of each food. This step is important for pupils to realize how much food has the indicated energy value.

The aim of the activity is to make the pupils realize that every food provides us with the energy that we can detect through food packaging. Subsequently, the pupils record the energy shown on the packaging in simple graphs in the worksheet. On the basis of these, they organize the foods according to the amount of energy they provide and compare the findings with the predictions.

Beverages may be used in a similar manner. Pupils can explore how much energy unsweetened mineral water, ice tea, cola drink, juice, etc. provides us. The aim is to realize that one also gets energy from various drinks, not just from food.