Types of Energy and Waves

1. Types of Energy and Waves Mr. Hollander’s 8th Grade Science Class

2. What is Energy??? • Energy is defined as the ability to do work or cause change • Work is done when a force causes an object to move in the direction of that force • Examples: Pushing a book off of the table is work and energy allows this work to take place • Energy is all around us all of the time being harnessedand expressed in different ways

3. Kinetic and Potential Energy • Kinetic energy is the energy of motion and/or movement • This is dependent on the mass and speed of an object • Note: Speed has more of an effect • Potential energy is energy that is stored and has the potential to do something • There are three types of P.E. • Elastic – Rubber band pulled back • Gravitational – Raising an object off of the ground (height & mass) • Chemical – A log being placed on a fire

4. Types of Energy • Mechanical – The total kinetic and potential energy of motion and position of an object • Thermal– The kinetic energy due to random motion of the particles that make up an object (Temperature and Number of Particles) • Chemical– The potential energy of a compound that changes as its atoms are rearranged • Electrical– The potential or kinetic energy of charged electrons • Sound– The kinetic energy caused by an object’s vibrations • Light– The kinetic energy caused by the vibrations of electrically charged particles • Nuclear– The potential energy caused by changes in the nucleus of an atom

5. Conservation and Conversion of Energy • Conservation of Energy is the idea that energy is not created or destroyed, but it can only change forms • Energy conversion explains this change from one form to another and happens all around us…everyday…all the time!!! • Example: A car uses chemical energy in a battery to create electrical energy to power an electric starter motor. This motor uses the electrical energy to create mechanical energy to start a vehicle. The vehicle converts chemical energy into mechanical energy to make the vehicle go.

6. What are Waves??? • Waves are a disturbance which transfer energy from one point to another with little or no transfer of matter • There are several parts of a wave: • Crest – The section of the wave above the undisturbed portion • Trough – The section of the wave below the undisturbed portion • Amplitude – The positive and negative amount of energy due to the disturbance • Wavelength – The distance between any two corresponding positions • Crest to Crest, Trough to Trough, Cycle to Cycle • Cycle – Start of the crest to the end of the trough • Period – The time of one complete cycle

7. Mechanical & Electromagnetic Waves • Mechanical Waves • Require a material medium to travel (air, water, ropes, etc.) • Three types of M.W. • Transverse; Up and Down (Pebble in a Pond) • Longitudinal; Side to Side (Sound) • Surface; Both transverse & longitudinal (Earthquakes) • Electromagnetic Waves • Do not require a material medium to travel (Light, Radio, Gamma)

8. Summing It All Up!!! • Energy is defined as the ability to do work or cause change • Kineticenergyis the energy of motion and/or movement (mass and speed) and potentialenergyis energy that is stored • The conservation of energy is the idea that energy cannot be created or destroyed but can only change forms • There are several types of energy; mechanical, thermal, chemical, electrical, sound, light and nuclear, this is constantly being converted from one form to another due to energy conversion • Wavesare a disturbance which transfer energy from one point to another with little or no transfer of matter • Mechanical waves require a medium in which to travel and an electromagnetic wave does not require a medium