ENERGY S8P2. Students will be familiar with the forms and transformations of energy. Explain energy transformation in terms of the Law of Conservation of Energy. Explain the relationship between potential and kinetic energy. Compare and contrast the different forms of energy (heat, light, electricity, mechanical motion, sound) and their characteristics.

What is Energy? In science, energy is the ability to do work or cause change. Work is done when a force causes an object to move in the direction of the force.

The Law of Conservation of Energy Energy CANNOT be created or destroyed, but it CAN change forms.

Types of Energy There are 2 main types of energy: Potential Energy (stored up energy) and Kinetic Energy (moving energy) **************************************** All forms of energy fall into one of these two categories.

There Are Seven Major Forms of Energy

Mechanical Energy Mechanical energy is the potential energy and the kinetic energy added together.

Sound Energy Sound energy is caused by an object’s vibrations. When an object vibrates, its vibrations transmit through the air so that we can hear it from another location.

Chemical Energy Chemical energy is the energy of a compound that changes as its atoms are rearranged.

Electrical Energy Electrical energy is the energy of moving electrons.

Light Energy Light energy is produced by the vibrations of electrically charged particles. Like sound vibrations, light vibrations cause energy to be transmitted.

Thermal Energy Thermal energy is all of the kinetic energy due to random motion of the particles that make up an object. Heat is thermal energy.

Nuclear Energy Nuclear energy, the energy that comes from changes in the nucleus of an atom. Fission is when the nucleus of an atom is split apart. Fusion is when the nucleus of two atoms are joined or “fused” together.

Kinetic Energy Kinetic energy, the energy of motion. An object has to be moving to have kinetic energy. The two factors that affect kinetic energy are: mass and speed.

Kinetic Energy To calculate Kinetic energy, use the formula: Kinetic Energy = ½ mass x velocity2 (where mass is in kg and velocity is in m/s) K.E. = ½ mv2

Kinetic Energy To calculate Kinetic energy, use the formula: Kinetic Energy = ½ mass x velocity2 (where mass is in kg and velocity is in m/s) K.E. = ½ mv2 Example: What is the kinetic energy of a 120kg object moving at a velocity of 2m/s?

Kinetic Energy To calculate Kinetic energy, use the formula: Kinetic Energy = ½ mass x velocity2 (where mass is in kg and velocity is in m/s) K.E. = ½ mv2 Example: What is the kinetic energy of a 120kg object moving at a velocity of 2m/s? K.E. = ½ x 120 x 22 K.E. = ½ x 120 x 4 K.E. = 240 Joules

Kinetic Energy 1. What is the kinetic energy of a 2000kg object moving at a velocity of 4m/s? 2. What is the kinetic energy of a 4kg bowling ball moving at a speed of 3m/s?

Potential Energy Potential energy is the energy stored in an object due to its position or condition. The factors that affect gravitational potential energy are: mass and height. A moving object can have potential energy as well as kinetic energy.

Potential Energy To calculate Graviatational Potential energy, use the formula: Gravitational Potential Energy = mass x height x gravity (where mass is in kg, height is in m and gravity is 9.8 m/s2) G.P.E. = mhg

Potential Energy To calculate Gravitational Potential energy, use the formula: Gravitational Potential Energy = mass x height x gravity (where mass is in kg, height is in m and gravity is 9.8 m/s2) G.P.E. = mhg

Potential Energy To calculate Gravitational Potential energy, use the formula: Gravitational Potential Energy = mass x height x gravity (where mass is in kg, height is in m and gravity is 9.8 m/s2) G.P.E. = mhg Example: What is the gravitational potential energy of a 2 kg vase resting on a shelf 3 meters high?

Potential Energy To calculate Graviataional Potential energy, use the formula: Gravitational Potential Energy = mass x height x gravity (where mass is in kg, height is in m and gravity is 9.8 m/s2) G.P.E. = mhg Example: What is the gravitational potential energy of a 2 kg vase resting on a shelf 3 meters high? GPE = 2 x 3 x 9.8 GPE = 6 x 9.8 GPE = 58.8 Joules

Potential Energy 1. What is the gravitational potential energy of a 5 kg book resting on a desk 12 meters high? 2. What is the GPE of a 100kg man standing on top of a hill 80 meters high?

Also known as light energy.

ENERGY TRANSFORMATIONS S8P2. Students will be familiar with the forms and transformations of energy. d. Describe how heat can be transferred through matter by the collisions of atoms (conduction) or through space (radiation). In a liquid or gas, currents will facilitate the transfer of heat (convection).

Thermal Energy or Heat Heat is energy that moves from an object at a higher temperature to an object at a lower temperature.

REMEMBER…the less molecules (mass) in a given space (or volume) the less dense it will be. Density=mass/volume

Conduction Conduction is the transfer of thermal energy from one substance to another through direct contact.

Convection Convection is the transfer of thermal energy by the movement of a liquid or a gas.

Some Examples of Convection Radiator Heater Convection Oven Ocean Currents

Heat Rises!

Convection Currents The vertical movement of air or liquid currents due to temperature variations.

Example of Convection in Nature Tempest in a Teapot: How Convection Brews a Storm - YouTube

Radiation Radiation is the transfer of energy by electromagnetic waves, such as visible light and infrared waves.

The Electromagnetic Spectrum