Energy Basics

Energy The ability to do work or cause change Either potential or kinetic

Potential Energy Energy that is stored. The snow on the mountain top represents potential energy.

Potential Energy Potential energy is highest when the object is at a higher point, like this roller coaster on the top of a hill. The higher the hill the greater the potential energy.

Potential Energy The more mass something has the greater its potential energy. In the picture below the man holding the weight above his head is holding a lot of potential energy.

Kinetic Energy The energy of motion

Kinetic Energy The faster the motion the greater the kinetic energy. When the roller coaster starts down the hill it has kinetic energy. The point where the car is going the fastest is where the kinetic energy is the greatest.

Forms of Energy Energy can be found in many forms Can be converted from one form or another Conversion can be both man made and a natural process Forms include chemical, thermal, elastic, radiant, mechanical and nuclear.

Chemical Energy Stored in chemical bonds holding the atoms of compounds together Food, wood, batteries, fossil fuels

Chemical Energy When a chemical reaction takes place energy is used. If energy is pulled in from the surrounding area during a chemical reaction, the area gets cold and the reaction is endothermic. Commercial ice packs for injuries work this way.

Chemical Energy When a chemical reaction takes place and releases energy it can increase the temperature. We call this an exothermic reaction.

Chemical Energy Plants can make their own energy through a process called photosynthesis. They are the bases for a food chain. All other living things that cannot carry on photosynthesis depend on plants for their energy.

Energy Transformation In photosynthesis radiant or light energy from the sun is changed to chemical energy in the leaf.

Chemical Energy Other living things can get energy from eating plants or eating things that eat plants.

Chemical Energy The energy we eat is stored as potential chemical energy until we need it. When we use the energy through an activity then it becomes kinetic mechanical energy.

Chemical Energy Plants make food through the process of photosynthesis. When we use the energy from the chemical energy we store we break it down through a process called respiration. These are opposite energy reactions.

Electrical Energy Energy of moving electrons Invisible but most useful form When the electrons are separated from positive charges and then forced along a closed path in a conduction material ex: copper

Energy Transformation Electrical energy can come from many different sources. The sources can be solar, nuclear, mechanical or generally chemical. In Texas most of our electricity comes from the burning of the coal, lignite. The energy transformation that takes place would be: Lignite (chemical)->moving turbines (mechanical)->moving electrons (electrical)-> our homes

Mechanical Energy Most familiar-involved with moving objects; atoms are moving and pushing each other Sound is an example-occurs when atoms in a media vibrate in a direction outward from the sound source. Sometimes, sound is classified as its own energy source.

Mechanical Energy When we move or work we are using mechanical energy.

Energy Transformations Automobiles use chemical energy (fossil fuels) which is converted to mechanical energy when they move.

Radiant or Light Energy Produced when atoms absorb energy from an outside source and release energy as electromagnetic radiation Most are invisible except for visible light UV rays, X-rays, radio waves

Radiant or Light Energy Our ultimate energy source is radiant energy from the sun.

Radiant or Light Energy In a light stick you have chemical energy stored in the vial. When you bend the stick and break it then light energy is released.

Radiant or Light Energy We use light energy in our homes. Many people have switched to compact fluorescent light bulbs over other light bulbs (incandescent) because they do not put out as much heat (thermal energy). The compact florescent bulbs are more energy efficient so they help in energy conservation.

Thermal Energy A special form of kinetic energy Energy of moving or vibrating molecules The faster the molecules vibrate the hotter they become When heat is produced we have thermal energy.

Thermal Energy Volcanoes can be a natural source of thermal energy. When we use the heat of the earth it is called geothermal energy.

Elastic Energy Energy stored in a solid object when it is either stretched or compressed. A stretched rubber band, compressed spring or jack-in-the-box

Nuclear Energy Energy stored in the nuclei of atoms Released by fission, the splitting of nuclei of heavy atoms Released by fusion-the combining of nuclei of light atoms

Nuclear Energy Einstein predicted the energy in a nuclear reaction before we had even split the atom in his famous equation: E = m c2 E=energy, m = mass and c2 is the speed of light. He is basically saying if we take the mass of an object and multiply it by the speed of light that will tell us how much energy it contains. This did not make a lot of sense at the time.

Nuclear Energy When the energy released from the splitting of an atom was discovered this made the equation make sense. There is an infinite amount of power in nuclear energy. This is what powers stars like our sun. Hydrogen is turned into helium. This process will continue until our sun runs out of hydrogen. This will be in about 4 billion years.

Nuclear Energy We are trying to harvest the power of the atom when we use nuclear energy.

Energy Basics There are many issues involved with energy. Renewable vs. Nonrenewable Energy Conservation Environmental Concerns Pollution These are just a few of the things you can study when studying energy.