ENERGY Bill Nye Energy https://www.youtube.com/watch?v=C4pnVGko0zU - PowerPoint PPT Presentation

ENERGY Bill Nye Energy https://www.youtube.com/watch?v=C4pnVGko0zU

What are kinetic and potential energy? CHAPTER 15 LESSON 1 Chapter Introduction • pages 554-557 Write Vocab terms • page 557 #1-5 Do the Investigate with • a partner pgs 558-559

ENERGY VOCABULARY CHAP15 LESSON 1 Energy - the ability to cause change in matter or do work Kinetic Energy - energy of motion Potential Energy - energy an object has because of its condition or position Energy transfer – movement of energy from one place or object to another Law of conservation of energy – energy can never be made or destroyed but it can change form

THE LAW OF CONSERVATION OF ENERGY • Energy can be neither created nor destroyed by ordinary means. • It can only be converted from one form to another.

THE LAW OF CONSERVATION OF ENERGY Potential energy is converted to kinetic then to mechanical or other forms. POTENTIAL ENERGY => KINETIC ENERGY => MECHANICAL ENERGY

THE LAW OF CONSERVATION OF ENERGY Sunlight (heat) is used by plants for Photosynthesis (to make food). It is converted to chemical energy. HEAT ENERGY => CHEMICAL ENERGY

THE LAW OF CONSERVATION OF ENERGY Oil and gas are burned in power stations to produce heat energy. It is used to turn turbines which produce electricity (electrical energy) HEAT ENERGY => ELECTRICAL ENERGY

THE LAW OF CONSERVATION OF ENERGY In an automobile engine, fuel is burned to convert chemical energy into heat energy. The heat energy is then changed into mechanical energy. CHEMICAL ENERGY => MECHANICAL ENERGY

Kinetic Energy energy of motion Potential Energy Stored energy https://www.youtube.com/watch?v=BWiYah08buI

POTENTIAL ENERGY ● The higher an object is, the more potential energy it has ● You can think of potential energy as kinetic energy waiting to happen.

KINETIC ENERGY • The faster an object moves, the more kinetic energy it has. • The greater the mass of a moving object, the more kinetic energy it has. • Kinetic energy depends on both mass and velocity.

ENERGY VOCABULARY CHAP 15 LESSON 2 page 570-574 Solar Energy - energy from the sun. Light Energy - energy in the movement of light particles Chemical energy – energy that is released by a chemical reaction (burning) Mechanical energy – combination of all the kinetic and potential energy that something has Electrical Energy - energy that flows through a circuit Nuclear Energy – energy that is released during nuclear fission to generate electricity

FORMS OF ENERGY The five main forms of energy are: Heat Chemical Electromagnetic Nuclear Mechanical

HEAT ENERGY ✓ Heat is a form of energy created by the movement of molecules ▪ substances change form when heated (solids, liquids, and gases) ✓ Heat energy can be produced by friction. ✓ If an object becomes hotter, it has gained heat energy.

CHEMICAL ENERGY ➢ Chemical Energy is required to bond atoms together. ➢ When chemical bonds are broken, energy is released. ➢ Fuel and food are forms of stored chemical energy.

MECHANICAL ENERGY ➢ When work is done to an object, it acquires energy. ➢ When you kick a football, you give mechanical energy to the football to make it move. ➢ When you throw a bowling ball, you give it energy, then energy is transferred through momentum.

ELECTROMAGNETIC ENERGY ➢ *EM waves can carry energy through places with or without any matter. ➢ *The Sun is the main source of EM energy on Earth. Part of this energy, light, is used by producers to make food. ➢ energy ➢ EM is carried by X-rays, radio waves, (R O Y G B I V) 22

➢ The nucleus of an NUCLEAR atom is the source ENERGY of nuclear energy. ➢ When the nucleus splits (fission), nuclear energy is released in the form of heat energy and light energy. ➢ Nuclear energy is the most concentrated form of energy.

ENERGY VOCABULARY CHAP15 LESSON 3 Heat – transfer of thermal energy between objects with different temperatures Conduction - transfer of heat from one object D irectly to another Convection – transfer of heat through the movement of a gas or liquid Radiation – transfer of heat from one place to another through light, sound, heat, or x-rays Reflection – bouncing of heat or light off an object

ENERGY VOCABULARY CHAP15 LESSON 3 Electromagnetic waves - waves of energy and light moving around us in many forms (solar, TV, radio, gamma, x-ray, heat) Conductor - materials that electricity or heat can easily flow through Insulators - materials that electricity or heat cannot easily flow through

HEAT TRANSFER ❖ Heat always moves from a warmer place to a cooler place. ■ Hot objects in a cooler room will cool to room temperature. (tea, coffee) ■ Cold objects in a warmer room will heat up to the room temperature. (butter, ice)

HEAT TRANSFER ❖ HOT objects expand, COLD objects contract ➢ Bridges expand on hot days and contract on cold days ➢ Wood expands when heated then contracts when cooled ❖ If an object: ➢ cools down, it means it has lost energy. ➢ If an object becomes hotter, it has gained heat energy.

Heat transfers in three ways: 1. Conduction 2. Convection 3. Radiation

ConDuction Con D uction is D irect contact, for example: ✓ warming your hands on a coffee mug ✓ cooking on a stove ✓ candy melting in your hands When you heat a metal strip at one end, the heat travels to the other end. As you heat the metal, the particles vibrate, these vibrations make the adjacent particles vibrate, and so on and so on. The vibrations are passed along the metal and so is the heat.

CONVECTION ➢ It is the way in which particles in a GAS or LIQUID move upwards, carrying heat with them ➢ Think about when you boil water, the bubbles move upwards ➢ Or think of a gas heater in the room, the heat rises around the room

Cools at the surface Cooler Convection water current sinks Hot water rises

ense Cooler, more d____, fluids sink through armer w_____, less dense fluids. In effect, warmer liquids and gases ise r___ up. ink Cooler liquids and gases s___.

CONVECTION: ATMOSPHERE ✓ Convection in the oceans and atmosphere helps to move thermal energy around the Earth. ✓ Hot air rises and cool air falls, causing a circular motion to create wind!

1. Why does hot air rise and cold air sink? Cool air is more dense than warm air, so the cool air ‘falls through’ the warm air. 2. Why are boilers placed beneath hot water tanks in people’s homes? Hot water rises. So when the boiler heats the water, and the hot water rises, the water tank is filled with hot water.

Radiation How does heat energy get from • the sun warming your body the Sun to the Earth? • a campfire warming your body • a light bulb causing heat There are no particles between the Sun and the Earth so it CANNOT travel by conduction or by convection.

Why are houses painted white in hot countries? White reflects heat radiation and keeps the house cooler. Why are shiny foil blankets wrapped around marathon runners at the end of a race? The shiny metal reflects the heat radiation from the runner back in, this stops the runner getting cold.

•Shiny materials - reflects heat • • •

REFLECTION AND ABSORBTION Two containers were filled with warm water. They were placed in direct sunlight. • The __________ container would reflect heat the most. shiny metal dull black • The __________ container would be the warmest after ten minutes Shiny metal Dull black radiation because its surface absorbs heat _______ the best (sun’s energy). shiny metal • The _________ container would be the coolest because it is the poorest at absorbing __________ heat radiation.

CONDUCTION VS. INSULATION

WHAT DO YOU THINK?

CONDUCTORS/INSULATORS ✓ If a substance easily allows heat to move through it, we can say it is a good conductor of heat. (metals) ✓ If a substance does not allow heat to pass through it easily we can say it is an Insulator. (wood, plastic, glass) ✓ Why do many sauce pans have plastic handles?

Conductors Insulators ➢ Wood ▶ Gold ▶ Platinum ▶ Water ➢ Styrofoam ▶ Silver ▶ Metal ▶ People and ➢ Glass Animals ▶ Copper ▶ Trees ➢ Porcelain ▶ Aluminum ➢ Plastic ➢ Rubber

Think about this! WHY DOES METAL FEEL COLDER THAN WOOD, IF THEY ARE BOTH AT THE SAME TEMPERATURE? ▪ Metal is a conductor…..it conducts heat away from your hands. ▪ Wood is an insulator…it doesn’t conduct the heat away from your hands as well as the metal, so the wood feels warmer than the metal.

CONDUCTOR OR INSULATOR? Wood? insulator Gold? conductor insulator insulator Plastic? Glass? Water? conductor Trees? conductor insulator Rubber?

ENERGY SOURCES AND ALTERNATIVE ENERGY