Monday 13 April 2015

RENEWABLE AND NON-RENEWABLE ENERGY SOURCES

We can classify the main energy sources into two groups:

Renewable energy sources. These sources will never run out. We can use them again and again, for example, the Sun, water and wind.


ENERGY

We need energy for everything we do.

There are many different forms of energy:
  • Electrical energy is the energy that makes machines in our homes work.

Monday 16 March 2015

SIMPLE MACHINES

Machines help us to save time and energy. They make work easier.

Machines with no or few moving parts are called SIMPLE MACHINES.

Some examples:

A wheel is a solid disk that turns on an axle. We use wheels to move things from one place to another.


Sunday 15 March 2015

PROPERTIES OF MATERIALS

When we make something, we choose materials according to their properties. A material can be:
  • Strong: It can support a lot of weight and force, for example, iron.

MATERIALS

Materials can be natural or man-made.

Natural materials are found in nature. They come from plants, animals, minerals and rocks. Wood, leather, cotton, wool and sand are all natural materials.
 
Cotton

Monday 9 March 2015

THE PHASES OF THE MOON

The Moon is a non-luminous body like the Earth. It reflects light from the Sun.

We can only see the part of the Moon that is illuminated by the Sun. This is why the Moon seems to change shape at different times of the month.

THE SEASONS

The Earth orbits the Sun. This causes the four seasons.

In the Northern Hemisphere the seasons are:


THE EARTH´S MOVEMENTS

ROTATION: The Earth continually rotates on its axis. It takes 24 hours, or one day, to make one complete rotation.

This movement causes day and night.

The Earth rotates anticlockwise on its axis. This means the Sun rises in the east and sets in the west.

THE EARTH

To study the Earth, we can use world maps. They show that most of the Earth´s surface is covered in water. The rest of the Earth consists of large masses of land separated by oceans, called continents.

There are six continents: Africa, America, Asia, Europe, Oceania and Antarctica


Tuesday 17 February 2015