Title: How to warm up in the winter?

Supplementary material for use in lessons in the group of natural sciences (nature, biology, chemistry, geography, physics), additional classes, science clubs. It can serve as a resource for expanding knowledge, preparing students for science competitions.

Lesson plan elaborated by Zyta Sendecka

Target Group

Students of the 7th grade of primary school (physics).

Core Curriculum

Grade VII – physics

IV. Thermal phenomena. Student:

7) describes the phenomenon of thermal conductivity; distinguishes materials with different conductivity; describes the role of thermal insulation.

The general aim of education

Students identify substances that are good and poor conductors.

Criteria for success

• you will discuss examples of good and poor heat conductors;

• you will observe the heat transfer process;

• you will describe examples of uses of good and poorly conductive materials.

Key Competences

• Communication in the mother tongue;

• Communication in foreign languages;

• Mathematical competence and basic competences in science and technology;

• Digital competence;

• Learning to learn;

• Social and civic competences.

Methods/forms of work

Talk, working with text, working with film, indirect observation, technique of traffic lights.

Frontal work and individual work.

Teaching aids

• abstract;

• interactive or traditional board;

• tablets/computers;

• electronic thermometer;

• three eggs;

• single‑burner electric stove;

• pot;

• water;

• containers of the same volume: Styrofoam, metal and plastic;

• student flip‑board.

Lesson phases

Introduction

1. The teacher asks students which substances are conducive to heat and which are not.

2. The teacher gives the subject and the purpose of the lesson in a language that the student understands as well as the criteria for success.

Realization

1. The teacher instructs the pupils to read the section entitled „Disappearing heat” and explains its title.

2. Students perform interactive exercise no. 1.

3. The teacher introduces a film illustrating thermal conductivity. He asks the pupils to write down the research question and the hypothesis in the form provided in the abstract. Then displays the movie. Students record the substances studied in the film and rank them according to the increase in their ability to transmit heat. They formulate conclusions and the teacher checks their accuracy.

4. Students independently perform interactive exercise no.2.

5. The teacher places one hot, boiled egg in each of the three containers: Styrofoam, metal and plastic. Students formulate a hypothesis. After 10 minutes, using an electronic thermometer, they measure the temperature of the eggs and verify their assumptions.

6. The teacher asks pupils to look at the pictures posted in the gallery („Gallery 1”) and discuss ways of using conductors and heat insulators.

7. Students independently perform interactive exercise no. 3 and interactive exercise no. 4.

Summary

1. The teacher asks pupils to assess the level of their knowledge gained during the course using the technique of traffic lights. Students raise colored sheets on their flip‑boards, where:

• green means that the students understand everything;

• yellow is a sign that they have some doubts, so they should read the selected sections of the abstract once again;

• red means that the students have not understood most of the information discussed in the lesson and must therefore read the whole of the abstract.

The following terms and recordings will be used during this lesson

Terms

Texts and recordings

How to warm up in winter?

Remember what happens when you take a warm bath – your body warms up. However, when you make a snowball in the winter, your hands freeze. Why is this happening?

Items warm up or cool because they take or give away heat. Heat flows (moves) from an object with a higher temperature to an object with a lower temperature.

The ability of a substance to conduct heat is called thermal conductivity. The substances that conduct heat well, we say that they are good heat conductors. All metals belong to this group, e.g. copper, silver. Materials that poorly conduct heat are called insulators. These include, for example, wood and polystyrene. All substances in the form of liquids and gases conduct heat poorly.

We know that heat can flow and that some substances protect against this process, while others - on the contrary - are good at it. Now look for answers to the question: How is heat transferred?

Heat flows from a warmer object to a colder one until their temperatures are even. Of course, the speed of this process depends on what materials these objects are made of. The better the heat conductors, the faster the temperatures will even out. It is easy to check by pouring warm water into Styrofoam and metal cups. As you already know, the water in the metal cup will cool down quickly, and in the Styrofoam will cool down slowly, because the polystyrene is a thermal insulator.

In Poland, we have to heat homes in winter. To reduce heat losses in buildings, materials that are poor heat conductors, eg mineral wool, Styrofoam, are used to insulate them. Insulated walls in the winter retain heat inside the building. In the summer, on hot days, the same materials ensures the heat from the outside does not get inside and the house is cooler. Similarly with clothes. In winter, we wear „layers”, that is, we put on many layers of clothing, between which there is air acting as an insulator. In the summer, we wear light, airy clothes that easily let heat through.

• Heat is transferred between materials (objects) that have different temperatures.

• The heat is transferred between the objects until their temperatures become even.

• Some substances conduct heat very well, we call them heat conductors (eg copper). Others conduct heat very poorly – they are heat insulators (eg polystyrene).