Primary 6 Science Energy Conversion 1. Where does our energy comes from? Most of our energy come from the ___________. (a) The sun gives off heat, light and other forms of energy. (b) Some of the heat and light reach the Earth. (c) Human and animals rely on the energy stored in food to keep us alive and to do work. (d) We also rely on energy stored in fuels to drive our machines in homes, schools and factories. 2. What are the different forms of energy? (a) Kinetic (movement) energy (b) Potential (stored) energy (c) Light (radiant) energy (d) Electrical energy (e) Sound energy (f) Heat (thermal) energy 3. What is kinetic energy? Kinetic energy is the energy ___________________ have. (a) Speed of object increases (b) Mass of object increases kinetic energy ____________. kinetic energy ____________. (c) Examples: Wind and moving water. 4. What is potential energy? Potential energy is the energy that is stored. (a) Object may gain potential energy if its ______________________. Example: A ball lifted from the ground has potential energy. (b) Higher an object is from the ground, __________ potential energy it has. (c) Greater the mass of an object, _________ potential energy it has. (d) An object may gain potential energy when its ___________________. Example: A squeezed ball and a stretched rubber band have potential energy to spring back to their original shapes. (e) Food and fuels contain potential energy. Example: Petrol, rice and bread. 5. What is light energy? Light energy is an energy that travels in the form of ____________________. (a) Light energy enables us to see an object when the object ____________ light into our eyes. (b) Our most important source of light is the __________. (c) Plant use light energy from the sun to carry out __________________. (d) Light can also be produced by using _______________ and _______________. 6. What is heat energy? Heat energy can be produced by electric current, a chemical reaction or friction. It is also produced by the sun. (a) Temperature is a measure of how hot or cold a substance is. (b) Heat flows from a warmer place to a cooler place. 7. What is electrical energy? Electrical energy is an invisible energy produced by the movement of electrons. (a) Electrons are tiny particles. (b) Electrical energy can be produced in ________________ and ________________. (c) Chemical reaction in a battery generate electric current. (d) Generators at the power stations provide most of the electricity used in homes and industries. 8. What is sound energy? Sound energy is produced by ________________________. (a) Sound travels in the form of ___________. (b) When sound travels through a material, the particles in the material vibrate and they collide. When they collide, energy is passed on from one particle to the next. (c) Sound is _____________ when it hits a soft surface. (d) Sound is _____________ when it hits a hard and flat surface. (e) An echo is a sound that is reflected from an object. (f) The louder the sound, the more energy the sound waves carry. 9. Conversion of Energy (a) Energy can be converted from one form into another. (b) The Law of Conservation of Energy states that energy can neither be created nor destroyed. (c) When an object gains or loses energy, the energy is transferred from one place to another or it is converted into a different form. (d) During photosynthesis, light energy is converted to potential energy. (e) In a simple electrical circuit, potential energy in a battery is converted electrical energy which is then converted to light, heat, sound or kinetic energy. (f) When electrical energy passes through electrical appliances, electrical energy is converted to light, heat, kinetic energy or a combination of different forms of energy.