Topic: Water - an amazing liquid

Target group

7th‑grade students of elementary school

Core curriculum

General aim of education

Students observe and distinguish between water concentration states.

Key competences

• communication in foreign languages;

• digital competence;

• learning to learn.

Criteria for success
The student will learn:

• describe the properties of various water concentrations;

• discuss the importance of water for living organisms;

• recognize the states of water concentration in nature.

Methods/techniques

• activating

  • discussion.

• expository

  • talk.

• exposing

  • film.

• programmed

  • with computer;

  • with e‑textbook.

• practical

  • exercices concerned.

Forms of work

• individual activity;

• activity in pairs;

• activity in groups;

• collective activity.

Teaching aids

• e‑textbook;

• notebook and crayons/felt‑tip pens;

• interactive whiteboard, tablets/computers;

• a camera or a mobile phone with a camera;

• glasses;

• cups;

• sets for building particle models;

• ice cubes.

Lesson plan overview

Before classes

• The teacher asks pupils to perform „Observation 1” at home and express their observations in the form of posters made according to jointly defined criteria.

Introduction

• The teacher asks the chosen student to answer the question: „Why are not water used to indicate temperature in thermometers?”.

• The teacher gives the topic, the goals of the lesson in a language understandable for the student, and the criteria of success.

Realization

• The teacher divides the class into four‑person teams. Members of each group compare their posters and choose the one that perfectly meets the requirements set out above. Groups hang out selected posters. Then the entire class assesses them and in accordance with the adopted criteria selects the winner. The teacher photographs the best poster, and his photo is sent by the charges.

• Students carry out the interactive exercises checking the level of knowledge learned during the lesson. The teacher initiates a discussion during which the correct solutions for all the exercises performed by the students are discussed.

• Students, working in groups, conduct „Observation 2”. After its implementation, the representatives of the groups in turn present the observations of the teams.

• The teacher presents and discusses the photo gallery. Students analyze the illustrations and answer the teacher's questions.

• The teacher asks volunteers to interpret the illustration „The amount of fresh water on Earth”. Students explain why water should be saved.

• The teacher announces a movie. He instructs his pupils to write a research question and a hypothesis in the form provided in the abstract. Then he plays the video and the students note their observations and conclusions. The teacher points the person who shares his insights and explains the reasonableness of the conclusions noted.

• The teacher gives groups the sets to build particle models and two mugs. Students present in their mugs the model of liquid water structure and the solid water structure model. The models are to consist of the same amount of water molecules. After completing the task, the students present their conclusions.

Summary

• The teacher asks students to carry out the recommended interactive exercise themselves.

Homework

• Listen to the abstract recording at home. Pay attention to pronunciation, accent and intonation. Learn to pronounce the words learned during the lesson.

The following terms and recordings will be used during this lesson

Terms

Texts and recordings

Water - an amazing liquid

Clean water has no taste, fragrance or color – only in large water reservoirs looks light blue. It is a liquid at room temperature. It freezes at 0°C and boils at 100°C. Many substances dissolve in it. In each state of matter it has its own separate name: in the solid state we call it ice, in the liquid state – simply water, and in the gas state – water vapor.

Properties of water may vary if it contains additives. We all know the term „salt water” – it is the water in the seas and oceans. Various substances, mainly salt, are dissolved in it. How, apart from the taste does sea water differ from „fresh water”, is it containing smaller amounts of salt? It is thicker, so that small objects can be kept on its surface. Maybe you've seen pictures from the Dead Sea, where you can see people floating on the sea surface effortlessly? This is due to the salinity – in the Dead Sea it is extremely large and amounts to 26% at the surface. For comparison, the salinity of the Baltic Sea is on average 0.7%.

Water occurs in our environment in all three states of matter. The fact that it exists in the form of liquid and ice, no one needs to convince us. But how to tell if there is water vapor around us? It's enough to cool it to condense.

Water plays a very important role in the life of organisms, including humans. It is necessary that various processes take place in our body, such as breathing or blood circulation, thanks to which we function properly. In our climate, an adult needs around 2.5 l of water a day. As a good solvent, this substance is also needed in many areas of human activity. During daily activities (eg. Washing, dishwashing), we consume up to 300 liters of water per day. Water is also used in industry (eg for the production of 1 kilo paper, 400 - 800 l of water is used) and agriculture – for watering crops.

Water, like all substances, reacts to changes in temperature – it therefore undergoes thermal expansion. However, in the case of water this phenomenon is different than in the case of other substances.

Usually density of the substance increases with the temperature drop. This means that if the temperature drops, the body with a given mass takes up a smaller volume. However, water has it’s highest density at 4°C. By lowering the temperature below this value, the water increases the volume again.

• In our environment, depending on the temperature, water can occur in three states – solid, liquid and gas.

• Water plays an important role in nature and in human life.

• Water has the highest density at about 4°C (it is the heaviest). Ice has a lower density (it is lighter) than cold water.