At the end of this unit, we will learn : •Example of where, when and why energy is used. •Various sources and forms of energy.•The examples of appliances that make use of energy transformation. •About ways of saving energy. •About ways of saving energy. •The reasons for the need to use energy wisely.
LESSON 1 : WONDER OF ENERGYLiving things carry out life processes. Energy is needed to carry outthese processes. •Living things need energy to breathe.
•Food produces energy for living things to grow•Living things need energy to move and do all kinds of work.
•Energy is also needed by non-living things. The energy is used to make them usable. The energy is used to move them. •The energy is used to change their state.
VARIOUS SOURCES OF ENERGY •The sun gives us heat and light energy. Plants use sunlight to make food. Humans and animals get energy from the food they eat. Their sources of food include plants and other animals. The sun’s heat dried the laundry.•Wind can be used to do work. A sail boat uses the wind energy to cruise.
•Fuel such as coal, petroleum and natural gas are sources of energy too.These fuels are formed from dead plants and animals that lived millions of years ago. •Dry cells can store energy for a long time.
LESSON 2 : ENERGY IN ACTION•Energy is found in different forms.•The batteries in a toy car produce electrical energy to move it. Objects thatmove have kinetic energy.
•A burning candle gives off light energy and heat energy.•A stretched rubber band in a catapult has potential energy.
CHEMICAL HEAT ENERGY LIGHT ENERGY ENERGY • Energy also can transformed from one another. A burning candle transforms chemical energy into light energy and heat energy. SOLAR ELECTRICAL LIGHT ENERGYENERGY ENERGY •Solar powered signal light uses sunlight as the sources of energy is transformed into electrical energy into light energy.
LESSON 3 : RENEWABLE OR NON- RENEWABLE•The energy we use every day comes from various resources. These resources are divided into renewable energy and non - renewable energy. •Renewable energy can be replenished when used up. SOLAR WIND BIOMASS WATER
•Non-renewable energy cannot be replenished when used up. NATURAL GAS NUCLEAR REACTOR COAL CHARCOAL PETROLEUM
WHAT CAN WE DO TO SAVE ENERGY?•Switch the lights and fan off when there is nobody in the room.
•Switch the computer or television off when you are not using them.
•Car pool or use public transport.•Develop new fuels for transport.