Sources of Electricity

Dry cells

Accumulators

Dynamos

Satellites get their electricity from solar cells.

Hydroelectric power station

Water Resources

Water is important to all living things. There are several uses of water at home such as:

                                                                     washing

                                                                             drinking

                                                                             bathing    

Water is also used as raw material in the food industries.

Water is home to many living things.

Water is needed to carry out many life processes such as transporting minerals in plants. Water is used by plants to make food.

Phases of the Moon

From the earth, the Moon looks like it is changing its shape. Actually it does not. It is caused by the different positions of the Moon that we see from the Earth. This is called the phases of the Moon. There are four major phases of the Moon. There are four major phases of the Moon

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Renewable or Non-renewable?

The energy we use every day comes from various resources. These resources are divided into renewable and non-renewable energy.

Renewable energy

Solar

Wind

Biomass

Water

Non-renewable energy
Natural gas

Nuclear reactor

Petroluem

Coal

Yeast is used to help dough to rise in making bread.

Bacteria and fungi cause dead organisms to decay to form natural fertilizers.

Fungi are used to produce antibiotics.





Here some harmful effects of microorganisms.

Eating food contaminated with microorganisms can cause food poisoning.

Bacteria act on the food remains between the teeth. This produces acid which causes tooth decay.

Food turns bad because of bacteria and fungi.

The Unseen Life

There are different types of microorganism. They are bacteria, protozoa, fungi and virus.

Bacteria exist in different shapes, sizes and colours.

                                           bacteria                                          

Most protozoa are found in ponds, lakes and rivers. Some of them eat other microorganism as food.

                                                                         protozoa

Fungi can be found on mouldy bread, rotten food, trees and forest floors.

 Virus is the tiniest microorganism. It can be found living in some bacteria, fungi, protozoa, animals, plants and humans.

                                                                             virus

Water Pollution

River is our source of drinking water. When it is polluted, the quality of drinking water becomes poor. The water contains harmful substances and bacteria that affects our health. The oil spills cover the water surface. This prevents oxygen in the air from dissolving in the water. Living things in the water will have less oxygen to breathe. How can we keep our resources clean? Avoid throwing rubbish into the river. Treating the sawage from houses, industries, and agricultural lands, and then releasing it into the river. Build factories far from river.

water pollution

Energy in Action

Energy is found in different forms. The batteries in a toy car produce electrical energy to move it. Objects that move have kinetic energy.

A burning candle gives off light energy and heat energy.

A stretched rubber band has potentiai energy.

A ringing telephone produces sound energy.

Changing States

When ice is left at room temperature, it will slowly melt. This process is called melting.

If we put water in the freezer, the water will turn into ice. This process is called freezing.

Boiling is a process that changes water into water vapour at a certain temperature.

When water is heated, the water at the surface changed into water vapour. The process is called evaporation.

The water droplets are formed when water vapour in the air turns into water as the side of glass is cold. This process is called condensation.

Starry, starry night

Big Dipper is a group of seven bright stars that form a pattern of a handle and a bowl. Orion and Big Dipper show the North Pole.

Scorpion can be seen clearly with its head, long body, tail and stinger between June and August.

Orion can be seen clearly as a hunter with a belt and sword between December and February.

Southern Cross can be seen as a brilliant cross in the southen sky. Southern Cross shows the South Pole.

  

Plant survival

These fruits are dispersed by water. They are covered with waxy skin.It prevents water from entering the fruit. Air spaces in the husk help the fruit to fruit.

Examples: coconut 

                

                                                pong-pong

These seeds and fruits are dispersed by wind. They are small, light, dry and have wing-like structure or fine hair. These characteristic help them to be flown for far away easily.

Examples: angsana  

      kapok

These seeds and fruits are dispersed by animals. Most of these fruits are brightly coloured, fleshy, edible and have smells. The seeds are usually hard.

Examples: mango 

       watermelon

Some fruits have hooks that can be attracted to animals.

Examples: mimosa 

          

These fruits disperse their seeds by explosive mechanism. They dry up and burst to push the seeds to push the seeds out from the fruits.
Examples: balsam

               

                 rubber seeds