1. Energy Review Notes

2.  Energy is what makes matter MOVE or CHANGE. We call this the ability to do WORK.  We studied 7 types of energy this year:  Mechanical  Radiant  Sound  Chemical  Electrical  Nuclear  Thermal  Energy can change from one form to another (chemical to electrical, electrical to light or heat…) What is Energy??

3.  Mechanical energy is the energy of moving parts  Moving things have energy. This is how running water or blowing wind can be captured and changed to electricity.  Potential energy is stored energy –no motion. (A rock at the top of a hill has potential energy).  Kinetic energy is energy from an object moving (the rock is rolling down the hill).  Remember the 6 simple machines –lever, wedge, screw, wheel & axle, pulley, inclined plane. Mechanical Energy

4.  Light energy allows us to see.  Plants use light energy to make food.  Transparent objects let all light though (like a window)  Translucent objects let some light through and will seem blurry (like wax paper)  Opaque objects do not let any light through (people are opaque –can’t see through us!)  We see colors because objects absorb some colors of light and reflect other colors. We ONLY see the colors that are reflected (a red shirt absorbs all the colors but reflects red, so we say that it is red).  Black absorbs more than white Radiant Energy (Light Energy)

5.  Reflection –When light BOUNCES off a smooth surface, like a mirror, we see a reversed image (just like math class!)  Refraction –When light BENDS as it goes through a substance like water or a lens. We see an image that is bigger, smaller, broken, or bent. Eyeglass lenses, telescopes, or cameras refract light. Light Energy – Important Terms Refraction Through A Lens Refraction

6.  Sounds is the energy of vibrations. Sound travels in waves.  A vibration is a fast back-and-forth movement.  An object must be vibrating to make sound.  To stop sound, stop the movement –when the vibration stops the sound stops!  Sound travels fastest through solids and slowest through gas. Sound cannot travel through space because there is no matter in space for sound to travel through. Sound Energy

7.  Chemical energy is energy created from chemical reactions.  Digestion is how the food we eat is changed into energy that our bodies use. This is chemical energy!  A battery uses stored chemical energy. The chemical energy changes to electrical energy when the battery is used. Chemical Energy

8.  Electricity travels in a closed circuit. A circuit must be CLOSED to work. A circuit has parts:  Energy Source (battery)  Energy output (light bulb, buzzer, hot plate)  Energy connectors (wires, conductors)  On/Off Switch (opens and closes the circuit)  Electrical energy can be transformed into other forms of energy like heat, light, sound, etc…  Conductors (like metal) keep electricity moving. Insulators (like plastic or rubber) stop electricity from moving. Electrical Energy

9. Types of Circuits Closed Circuit Series Circuit Parallel Circuit

10.  Thermal energy is also called heat energy.  Heat is the energy of moving particles.  Heat always travels from a hotter object to a cooler object.  Heat travels in 3 ways:  Conduction –when objects touch (a pot touching a hot stove will become hot)  Convection -heat through currents of air or water (hot air or water rises and creates moving heat)  Radiation –when heat travels through space (the Sun, a campfire) Thermal (Heat) Energy

11.  A force is a push or pull that causes an object to:  Start moving*Stop moving  Change direction*Or change speed  Some forces are invisible. Remember these:  Gravity –an invisible force that pulls everything to the ground  Magnetism –an invisible force that pulls iron or steel objects toward a magnet.  Friction –an invisible force caused by two objects rubbing together. It makes moving things slow down or stop. Smooth surfaces (ice) have less friction and rough surfaces (carpet) have more friction. Force and Motion

12.  The Sun is the most important source of energy for Earth. Without the Sun’s energy we would not have:  A water cycle  Wind  Food chains REMEMBER