ENERGY

ENERGY? Energy drives our world. Energy drives our world. We put it in our cars, food in our stomachs, and batteries in our toys because everything in our world needs energy to make it happen. We put it in our cars, food in our stomachs, and batteries in our toys because everything in our world needs energy to make it happen.

Energy makes our world buzz with light, color, sound, and motion. Energy makes our world buzz with light, color, sound, and motion. Without energy, life would not be possible- nothing could grow, move or feel and the world would be a dark, cold and lifeless place. Without energy, life would not be possible- nothing could grow, move or feel and the world would be a dark, cold and lifeless place.

Where does it all come from? Most of our energy Most of our energy comes from the sun. Where did the sun get all its energy from? Scientists believe it came from the Big Bang Scientists believe it came from the Big Bang No more energy has been created since or will it ever be made in the future. No more energy has been created since or will it ever be made in the future.

Energy is Everywhere Everything in the world involves energy changing from one form to another. Everything in the world involves energy changing from one form to another. Water in a water bottle. Water in a water bottle. Sneakers on your feet. Sneakers on your feet. Muscles in your body. Muscles in your body.

How do we define ENERGY? Energy can be defined as the ability to do work. Energy can be defined as the ability to do work. If an object or organism does work (exerts a force over a distance to move an object) the object or organism uses energy. If an object or organism does work (exerts a force over a distance to move an object) the object or organism uses energy.

How do we measure energy? Because of the direct connection between energy and work, energy is measured in the same unit as work: joules (J). Because of the direct connection between energy and work, energy is measured in the same unit as work: joules (J). James Prescott Joule

Forms of Energy Energy is recognized in seven forms all of which a kinetic or potential Energy is recognized in seven forms all of which a kinetic or potential Thermal (heat) Thermal (heat) Mechanical (motion) Mechanical (motion) Chemical Chemical Nuclear Nuclear Electrical ( electricity, lighting) Electrical ( electricity, lighting) Radiant/ Electromagnetic (light, x-rays) Radiant/ Electromagnetic (light, x-rays) Sound (Motion) Sound (Motion) The Man Could Not Even Remember Snow!

Potential vs. Kinetic All forms of energy fall under two categories. All forms of energy fall under two categories. Potential energy is stored energy. Potential energy is stored energy. Kinetic energy is motion. Kinetic energy is motion.

Potential vs. Kinetic All forms of energy fall under two categories. All forms of energy fall under two categories. Potential energy is stored energy. Potential energy is stored energy. Kinetic energy is motion. Kinetic energy is motion. As a basketball player throws the ball into the air, various energy conversions take place. As a basketball player throws the ball into the air, various energy conversions take place.

Ball slows down Ball speeds up

Kinetic-Potential Energy Roller coasters work because of the energy that is built into the system. Initially, the cars are pulled mechanically up the tallest hill, giving them a great deal of potential energy. From that point, the conversion between potential and kinetic energy powers the cars throughout the entire ride.Roller coasters work because of the energy that is built into the system. Initially, the cars are pulled mechanically up the tallest hill, giving them a great deal of potential energy. From that point, the conversion between potential and kinetic energy powers the cars throughout the entire ride.

Radiant Energy Electromagnetic energy that travels in transverse waves. Electromagnetic energy that travels in transverse waves. Visible light Visible light X-rays X-rays Gamma rays Gamma rays Radio waves Radio waves

Thermal Energy The internal motion of the atoms is called heat energy, because moving particles produce heat. The internal motion of the atoms is called heat energy, because moving particles produce heat. Heat energy can be produced by friction. Heat energy can be produced by friction. The faster the molecules move, the more heat energy is produced. The faster the molecules move, the more heat energy is produced. Examples: Examples: Friction Friction Phase change Phase change

Sound The movement of energy through objects or substance in longitudinal waves

Chemical Energy Energy stored in the bonds that hold atoms together. Energy stored in the bonds that hold atoms together. When bonds are broken, energy is released. When bonds are broken, energy is released. Examples: Examples: Digesting food…bonds are broken to release energy for your body to store and use. Digesting food…bonds are broken to release energy for your body to store and use. Sports… your body uses energy stored in your muscles obtained from food. Sports… your body uses energy stored in your muscles obtained from food. Fire–a chemical change. Fire–a chemical change.

Nuclear Energy Energy stored in the nucleus of an atom. Nuclear energy is the most concentrated form of energy. When the nucleus splits (fission), nuclear energy is released in the form of heat energy and light energy. Nuclear energy is also released when nuclei collide at high speeds and join (fuse – “fusion”)

The sun’s energy is produced from a nuclear fusion reaction in which hydrogen nuclei fuse to form helium nuclei.

Stored Mechanical Energy Energy stored in objects or substances by the application of force. Energy stored in objects or substances by the application of force.

Gravitational Potential Energy The energy of place or position. The energy of place or position. A waterfall, a suspension bridge, and a falling snowflake all have gravitational potential energy. A waterfall, a suspension bridge, and a falling snowflake all have gravitational potential energy.

Energy Conversion All forms of energy can be changed from one form to another. Changes in the form of energy are called energy conversions. All forms of energy can be changed from one form to another. Changes in the form of energy are called energy conversions. The sun’s energy through solar cells can be converted directly into electricity. The sun’s energy through solar cells can be converted directly into electricity. Green plants convert the sun’s energy (electromagnetic) into starches and sugars (chemical energy). Green plants convert the sun’s energy (electromagnetic) into starches and sugars (chemical energy).

Other energy conversions In an electric motor, electromagnetic energy is converted to mechanical energy. In an electric motor, electromagnetic energy is converted to mechanical energy. In a battery, chemical energy is converted into electromagnetic energy. In a battery, chemical energy is converted into electromagnetic energy. The mechanical energy of a waterfall is converted to electrical energy in a generator. The mechanical energy of a waterfall is converted to electrical energy in a generator.

Energy Conversions In an automobile engine, fuel is burned to convert chemical energy into heat energy. The heat energy is then changed into mechanical energy. In an automobile engine, fuel is burned to convert chemical energy into heat energy. The heat energy is then changed into mechanical energy.

The Law of Conservation of Energy Energy can be neither created nor destroyed by ordinary means. Energy can be neither created nor destroyed by ordinary means. It can only be converted from one form to another. It can only be converted from one form to another.