Transcript Document
ENERGY is… the ability to do WORK or cause change Name 2 things that ARE energy or that HAVE energy WORK is… when a FORCE moves an object a FORCE is… a push or a pull There are two main kinds of energy… POTENTIAL ENERGY STORED energy or Energy that is NOT being used Examples: KINETIC ENERGY Energy in MOTION or Energy that IS being used Examples: Write a “P” or a “K” under each picture on your paper to tell whether the pictures are showing POTENTIAL or KINETIC energy. zzzz K P K K P Gravitational Potential Energy Gravitational Energy is the energy of position or place. A rock resting at the top of a hill contains gravitational potential energy. Hydropower, such as water in a reservoir behind a dam, is an example of gravitational potential energy. Gravitational Potential Energy Gravitational Energy is the energy of position or place. A rock resting at the top of a hill contains gravitational potential energy. Hydropower, such as water in a reservoir behind a dam, is an example of gravitational potential energy. DIFFERENT FORMS OF ENERGY Both potential & kinetic energy come in many forms. Six of the most common ones are: Sound Energy Energy of virbrating particles THERMAL (HEAT) ENERGY Energy of the heat IN an object CHEMICAL ENERGY Energy in chemical bonds of food, gas, batteries, burning wood etc. DIFFERENT FORMS OF ENERGY (continued) ELECTRICAL ENERGY Moving electrical charges ELECTROMAGNETIC ENERGY (light/radiant) Light energy, X-rays, radio waves NUCLEAR ENERGY Stored in the nucleus of an atom & released when atoms are split or joined together, nuclear reactors, atomic bombs, stars, sun Sound energy is the energy produced by sound vibrations as they travel through air, water, or any other space. This type of energy is a form of mechanical energy. Most people and animals can register this sort of energy with their ears and it’s fairly easy to identify. SOUND ENERGY Thermal energy is the energy that comes from heat. This heat is generated by the movement of tiny particles within an object. The faster these particles move, the more heat is generated. Stoves and matches are examples of objects that conduct thermal energy. THERMAL ENERGY The energy that results during a chemical reaction is called chemical energy. It is a type of potential energy. Chemical energy is stored within the bonds of the atoms and molecules that make up a substance. Once chemical energy is released from a substance, the substance is transformed into a new substance. CHEMICAL ENERGY Electrical energy is energy that is caused by moving electric charges. Since the electric charges are moving, this is a form of kinetic energy. The faster the electric charges are moving the more electrical energy they carry. ELECTRICAL ENERGY The potential for light to perform work is called light energy. Light energy is the only form of energy that we can actually see directly. Light energy can also be converted into other forms of energy. ELECTROMAGNETIC (LIGHT) ENERGY 1.The energy released by a nuclear reaction, especially by fission or fusion. 2. Nuclear energy regarded as a source of power. Also called atomic energy. NUCLEAR ENERGY ENERGY CONVERSIONS (ENERGY TRANSFORMATIONS) Energy can be converted (transformed or changed) from one form to another. For example… 1) Food has POTENTIAL CHEMICAL energy. 2) When you eat it, the bonds in the atoms are broken and the energy is released to your cells. 3) Your body CHANGES the chemical energy to KINETIC MECHANICAL ENERGY when you run, jump, write, walk. 4) Finally, your body creates THERMAL (HEAT) ENERGY you can feel because the molecules inside you are moving! Think about the energy conversions taking place with a flashlight. Use the flow chart in your notes to show each form of energy that occurs. Batteries CHEMICAL ENERGY Wires ELECTRICAL ENERGY Lightbulb ELECTROMAGNETIC (Light)ENERGY Label the ENERGY CONVERSIONS in your notes. ELECTRIC PENCIL SHARPENER WIRES electrical energy GEARS & BLADES mechanical energy HEATING PAD WIRES electrical energy HEAT thermal energy PLANT SUN PHOTOSYNTHESIS Plant changes sunlight and water into sugar (food) for plant! electromagnetic (light)energy chemical energy Energy Transformations Conversions Between Forms of Energy A change from one form of energy to another is called energy conversion. Most forms of energy can be converted into any other form. Ex. Toaster converts electrical energy to thermal energy. Your body converts chemical energy in the food you eat into the mechanical energy you need to move your muscles. Usually heat energy is also formed in an energy conversion. Electrical Energy into Thermal Energy Chemical Energy into Mechanical Energy DO NOW With your elbow buddy: I will pass out an index card. Keeping the fold up, use two hands to pull the ends out to flatten out the card. Predict what will happen to the card as you let go. Test and then explain your prediction. Use the terms potential and kinetic energy. CONSERVATION OF ENERGY P.E K.E. P.E. K.E. … Is energy lost? No! Energy is converted! Law of Conservation The law of conservation of energy states that when one form of energy is converted to another, no energy is destroyed in the process. Energy cannot be created or destroyed, so the total amount of energy is the same before and after any process. All energy is accounted for. Conserving Energy When you hear or read about conserving energy, don’t get confused with the law of conservation of energy. Conserving energy means saving energy, or not wasting it! In Science, energy is always conserved because its total quantity does not change. http://tonto.eia.doe.gov/kids/energy.cfm?p age=about_home-basics LAW OF CONSERVATION OF ENERGY Energy can be neither created nor destroyed. The total energy in a “closed” system is always the same. The energy may be in different forms, but the amount will be equal. Energy Conversion in a Waterfall The water at the top of the falls has gravitational potential energy because it is higher than at the bottom. As the water falls, its height decreases, and loses its potential energy. At the same time, its kinetic energy increases because its velocity (speed) increases. The potential energy is converted into kinetic energy. Gravitational Potential Energy Kinetic Energy Qu i c k T i m e ™ a n d a T I F F (U n c o m p re s s e d ) d e c o m p r e s s o r a re n e e d e d t o s e e t h i s p ic t u re . CONSERVATION OF ENERGY Thermal Energy produced by friction is not useful energyWhy? It IS NOT used to do work. PERPETUAL MOTION A machine that would run forever without the addition of energy. Some energy is wasted due to the thermal energy produced, so perpetual motion is not possible. So How does the “drinking bird” work?