What is Energy?
Energy is the ability to do work ( to make an object move )
Examples of work:
- eating, digesting
We learned that kinetic energy can transfer from one object to another.
We practiced reading graphs to decide the speed and direction of travel.
We learned that the taller ramp provided the car with more potential energy, which meant that the car then had more kinetic energy for rolling.
Different Forms of Energy
- Heat (thermal) comes from the motion of tiny particles in matter. An oven or heater are examples of heat energy.
- Light (solar) comes from the the sun. Plants use it to make food. Lasers and suntans are examples of light energy.
- Sound energy comes from sound waves, like through speakers or your voice box. It often feels like vibrations.
- Electrical energy comes from the movement of charged particles. Electricity comes from power plants that burn fuels to make the electricity before sending it through wires to homes and businesses.
- Chemical energy comes from the breaking down of food, fuel, and other kinds of matter. Burning a log or digesting your lunch to get energy are examples.
- Nuclear energy comes from nuclear power plants that break apart tiny particles of matter.
- Mechanical energy comes from matter that is in motion. Wind and rushing water both have mechanical energy that we can collect.
Energy can change forms. For example, electrical energy changes to light energy when you turn on a lamp. Chemical energy changes to heat energy when you burn a log fire.
Heat Energy Transfer
Open and Closed Circuits
Closed circuits have all pieces connected. Closed circuits allow electricity to flow.
Open circuits have a break in the circuit. There is a hole, so electricity cannot flow.
Parallel and Series Circuits
Force and Motion
A push or a pull is a force. Forces can be big or small, like lifting a truck or pushing a button on a keyboard. Gravity is a huge force. Another important force is friction. Friction is force that acts between surfaces of objects that touch. Friction causes objects to slow or stop. Objects will stay moving until a force, like friction, stops them. Similarly, objects will stay still until a force causes them to move. This is called inertia.
Newton's first law of motion says that objects in motion will stay in motion until acted on by another force. Similarly, objects at rest will stay at rest until acted on by another force. For example, a soccer ball will stay still until a force, like a kick, makes it move. The same soccer ball will keep moving until a force, like friction, makes it stop.
Newton's second law of motion says that an object will move in the direction of a force. For example, if a soccer ball is kicked to the North, the ball will move in that direction. If it is kicked to the South, the ball will move in THAT direction. If a football player tackles an opponent while running downfield, the opponent will move in the downfield direction.
Newton's third law of motion says that every action has an equal and opposite reaction. This means that a stronger force will result in a bigger reaction. For example, if you bump into your friend while walking, they may stumble a little bit. If you bump into your friend while running, they will probably stumble a lot. Imagine the reaction that would result if the force (you) was even stronger (like, you were wearing a jet pack and traveling at 100 miles per hour)!
Renewable and Nonrenewable Resources
Natural resources are materials that people get from nature and use to live our daily lives.
Renewable resources are energy sources that cannot be used up.
Nonrenewable resources are energy sources that can be used up and will eventually run out.