Дистанційне навчання 2020

PACE WORK (Science)13/05

Тема: Стани речовини

Основна частина уроку

1.      Reading

T: Read the text, then match the pictures to the parts of the text.

Introduction of the new material

T: Match the words to their meanings:

1)      Solid                             a) запобігати                     

2)      Bound                           b) рух

3)      Phase of matter             c) твердий стан

4)      Prevent                          d) зв’язувати

5)      Movement                      e) об’єм

6)      Volume                            f) стан речовини

7)      Absent                              g) відсутній

Materials have a solid, liquid and gas form. Each of these forms is known as a phase of matter. In each of its phases the particles of a substance behave very differently. A substance can change from one phase to another through what is known as a phase transition. These phase transitions are mainly the result of temperature changes.

Solid

When a material is in its solid phase, molecules are bound together tightly. The shape and volume of a solid is usually fixed. The forces that attract particles to one another are particularly strong in solids, keeping them close together in specific positions. This helps to prevent a solid from breaking apart or being compressed. The density of solid material increases at lower temperatures. The colder the temperature, the weaker the vibrations of particles, making them pack together even tighter. Solids can be classified as crystalline, with particles arranged tightly in geometric patterns, or they may be classed as amorphous solids. The crystals in amorphous solids, such as clay, are arranged more loosely and randomly, allowing the shape of the material to be altered.

Liquid