Title: Is it possible to change the shape of solids?

Lesson plan elaborated by: Zyta Sendecka

Target Group

Pupils of the 4th grade of primary school (new curriculum)

Core Curriculum

The general aim of education

Students learn about the properties of substances.

Criteria for success

• you will explain what the properties of substances are;

• describe a substance as being brittle, plastic or elastic;

• provide examples of brittle, elastic and plastic substances and discuss their applications.

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, work with the text, direct observation, indirect observation, brainstorming.

Individual work, group work and frontal work.

Teaching aids

• abstract;

• interactive or traditional board;

• tablets/computers;

• various substances: crystal sugar, flour, citric acid, water, glass, thin wire, chalk, plasticine, clay, eraser, sponge, spring, metal rod and others with differing physical properties like colour, state of matter, smell;

• work sheet (Appendix 1).

Lesson phases

Introduction

1. 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 presents various materials (crystal sugar, flour, citric acid, water, glass, thin wire, chalk, plasticine, clay, eraser, sponge, spring, metal rod with differing physical properties like color, state of matter, smell). Asks pupils to observe them using their senses of sight and smell, and then complete the work sheet (Appendix 1), specifying the physical state of the substance, their color and scent. Students present their observations, the teacher corrects possible mistakes.

2. The teacher instructs students to write in their notebooks the definition of the concept of substance properties, using abstract if necessary.

3. The teacher divides the students into three‑person groups. Each team performs observations of the substances shown by the teacher, checking what happens to them when attempting to change their shapes. Members of the group collectively determine the names of these properties of the substance (brittleness, plasticity, elasticity) and write them in the blank headings of the table in the work sheet. Then they fill in the next columns.

4. The teacher asks group representatives to present the results of the work and assesses the accuracy of their work.

5. The teacher introduces a movie entitled „How is a glass tile formed?” and explains the experiment presented in it. He instructs the pupils to set a research question and a hypothesis regarding the plasticity of the substance. Students write them in the form provided in the abstract. The lecturer displays the video and the students record their observations and conclusions. The teacher assesses their accuracy.

Summary

1. Students independently perform an interactive exercise.

2. The teacher asks students to write „Recommendation 2.1” in writing and defines the criteria for assessing the task performed:

• presentation of three correct arguments – very good;

• presentation of two correct arguments – good;

• presentation of one correct argument – okay.

The following terms and recordings will be used during this lesson

Terms

Texts and recordings

Is it possible to change the shape of solids?

Each substance has specific properties, i.e. a set of constant, invariable characteristics (eg colour, smell, hardness) that allow it to be distinguished from other substances.Thanks to its different properties, one substance can be used to create completely different objects. For example, the substance called silicone is resistant to high temperatures, that's why it is used to make baking moulds. Another property of silicone, water resistance is used in the production of paints containing this substance.

We already know that every substance has characteristic features and properties. Solids can also be classified according to how they behave when trying to change their shape.They may break when bent (brittle substances), change their shape permanently (plastic), or return to it’s previous shape (elastic).

Substances can be divided into brittle, elastic and plastic – depending on how they react to changes in shape. Each of these features means that individual substances are used for various purposes. For example, clothes would slide off of you, if not for the elasticity of the cuffs. Elastic materials are used in many sports equipment. Due to the plasticity of different materials, wires can be rolled. Brittle substances also have many applications. Despite the name, they are not always fragile. For example, a concrete slab is brittle, but you certainly wouldn’t be able to break it. One use of brittle substances is in construction.

Imagine a house made of plastic or elastic material. Would it be possible to live in it comfortably? Justify your answer.

• Substances can be divided due to their susceptibility to deformations, like; brittleness, elasticity and plasticity.

• Brittle substances are those that can burst (break) under the pressure.

• Plastic substances change shape under pressure but do not return to their former form.

• Elastic substances change shape under pressure and return to their previous form.

• Knowledge of a substances properties is used in the manufacture of objects used by us in everyday life.

• Among the substances, metals can be distinguished. They are characterized by such properties as: good thermal and electrical conductivity, ductility and malleability and metallic gloss.