· Theme: Investigating Materials
· Learning Area: Food Preservation
· Learning Objective: Synthesising the concept of food preservation
Pupils should be able to:
· describe ways to preserve food;
· give examples of food for each type of food preservation;
· give reasons why each way of food preservation is used.
· ways to preserved food;
· examples of food for each type of preservation.
· Observing, classifying, making inferences, interpreting data, making conclusions, comparing and contrasting.
Vocabulary/ New Words:
· food spoilage, microorganisms, pickling, pasteurising, smoking, waxing, vacuum packing
· Having an interest in and curiosity about the environment.
· Being diligent and persevering.
· Realising that science is a means to understand nature.
· Thinking rationally
· Analysing the things around us
Point(s) to Note:
Explain and give examples of each type of food preservation
Show video on breads that mould. Ask pupils to observe what will happen when bread is becoming bad. Explain to pupils that mucor is an example of fungi, which is a type of microorganism, Encourage pupils to give the conditions that allow microorganisms to grow.
Play the content component. Ask pupils what is the benefit of preserving food. Teacher explains that food is preserved to ensure that it lasts longer for future use. Explain that microorganisms cause food spoilage. Ask pupils why food can last longer when it is preserved. Explain that food preservation prevents or slows down microorganism growth.
Play the content component. Ask pupils to observe the different types of food. Ask pupils what the methods to preserve food and examples of the types of food are.
Play the content component. Teacher introduces vacuum packing. Ask pupils how vacuum packing works. Explain that air needs to be removed before sealing the bag and vacuum is thus created. Ask pupils the examples of food that can be vacuum packed. As mircoorganisms need air to live and grow, air removed due to vacuum packing can preserve food.
Play the content component. Teacher introduces pickling. Ask pupils how pickling works. Explain that food is kept in solution of vinegar, salt or sugar. Ask pupils the examples of food that can be pickled. As mircoorganisms cannot survive in acidic, highly salty or highly sweet conditions, pickling creates an unsuitable condition for microorganisms.
Play the content component. Teacher introduces pasteurisation. Ask pupils how pasteurisation works. Explain that food is heated, cooled down quickly and then packed in sterile containers. Ask pupils the examples of food that can be pasteurised. As mircoorganisms live in room temperature, they are destroyed in high temperature during pasteurisation.
Play the content component. Teacher introduces smoking. Ask pupils how smoking works. Explain that food is dried with smoke, where there is a flameless fire with emission of smoke only. A regulated heated is required. Ask pupils the examples of food that can be smoked. Smoking forms a protective coat on the food. Explain that smoking food slows down its spoilage.
Play the content component. Teacher introduces waxing. Ask pupils how waxing works. Ask pupils the examples of food that can be waxed. Ask pupils what are benefits of waxing. Explain that the food would last longer and look better. It helps the colour of fruit skins look more vivid. Wax prevents microorganisms from growing on the food.
Play the content component. Teacher recaps the methods of preserving food and the benefits they bring.
Play the activity component. Match the types of food preservation correctly. Drag and drop to match the correct answer.
There are five questions in this component covering the learning outcomes. Questions 1 to 3 are objective questions. Q4 is a drag and drop activity. Pupils drag and drop the correct answers for the questions. Q5 consists of true or false questions. Pupils need to identify whether the statements are true or false.
Use evaluation sheets to assess the pupils’ understanding of this lesson.
Conduct a study on how ancient people preserved and stored their food for future use. Give ways on how ancient people preserved their food. They kept the food in dry place. They used salt, sugar and vinegar to preserve food. They put certain kinds of dry leaves to absorb the moisture in containers.
Conclude the lesson by playing this component to further reinforce understanding of the lesson. Help pupils to describe ways to preserve food. Give examples of food for each type of food preservation. Emphasise that some methods of food preservation are used because of certain reasons.