Its various forms and how we respond to energy Energy Cont… Its various forms and how we respond to energy

Energy types There are many forms of energy! The most common forms are: Mechanical Sound Chemical Radiant Electrical Thermal (heat) Nuclear

Mechanical Energy The total amount of work an object can do because of the object’s kinetic and potential energies. ME = potential energy + kinetic energy Examples?? The total energy of motion and position of an object. ME can be all potential or all kinetic or some of both. Flying bird or running water

As a pin is juggled, its ME is the sum of it’s potential and kinetic energy at any point. ME of an object remains the same unless it transfers some of its energy to another object. Even if the ME of an object stays the same, the potential or kinetic energy can increase or decrease. Juggler is doin work on the pin with his hand but once of the pin leaves his hand the kinetic energy starts to change into potential. Kinetic energy is decreasing because the pin starts to slow down. Eventually all the pins kinetic energy changes to potential and it stops moving upwards.

Sound Energy Relates to the repetitive compression (squeezing) and rarefaction (letting out) of molecules in a substance (solid, liquid or gas). Sound energy is caused by an objects vibrations. Examples?? Guitar Buzzing bee horns

When you stretch a guitar string, the string stores potential energy When you stretch a guitar string, the string stores potential energy. When you let the string go this potential energy is turned into kinetic energy which makes the string vibrate. The string also transmits some of its kinetic energy to the air around it. The air particles also vibrate, and transmit this energy to your ear. When the sound energy reaches your ear, you hear the sound of the guitar.

Chemical Energy Related to the potential energy stored in the bonds between atoms in a compound. The energy of a compound changes as its atoms are rearranged. Chemical energy is form of potential energy because it depends on the position and arrangement of the atoms in a compound. Examples?? Food Glow sticks Matches Fossil fuels/burning wood

Glow sticks emit light when two chemicals are mixed Glow sticks emit light when two chemicals are mixed. The sticks consist of a tiny, brittle container within a flexible outside container. Each container holds a different solution. When the outer container is flexed, the inner container breaks, allowing the solutions to combine, causing the necessary chemical reaction. After breaking, the tube is shaken to thoroughly mix the two components.

Radiant (Light) Energy Produced by the vibrations of electrically charged particles that create electromagnetic waves that can travel through a vacuum such as space. Light energy is a type of kinetic energy with the ability to form types of light people can see as well as invisible waves. Light energy is very fast, and nothing travels faster!! Examples?? They do not require a presence of material medium to transmit their energy. Light bulb Microwave

Light energy that we can see and energy that we cannot see

Electrical Energy Related to the movement or flow of electrons which carry a charge. Since the electric charges are moving, this is a form of kinetic energy. The faster the electric charges are moving the more electrical energy they carry Electrons are the negatively charged particles of atoms. Examples?? Electrical outlet Generator

Electrons are flowing through these wires.

Thermal (Heat) Energy All matter is made up of particles that are always in random motion. Because the particles are in motion, they have kinetic energy. Thermal energy is all of the kinetic energy due to random motion of the particles that make up an object. Particles move faster at higher temperatures and slower at lower temperatures. The faster the particles move, the greater their kinetic energy and the greater the objects thermal energy.

Nuclear Energy Related to the potential energy stored in bonds between particles in the nucleus of an atom. Atoms store a lot of potential energy because of the position of the particles in the nucleus of the atoms. When 2 or more small nuclei join together, or when the nucleus of a large atom splits apart, energy is given off. Examples?? The sun

The sun’s energy is produced from a nuclear fusion reaction in which hydrogen nuclei fuse to form helium nuclei.

Energy Conversions Is a change from one form of energy to another. Any form of energy can change into any other form of energy. Often one form of energy changes into more than one other form. Give me examples!!!

Electrical energy in the wiring of a home gets converted to light energy and thermal energy when a light swtich is turned on.

Energy Conversion cont…. Trace the conversion of light energy from the sun to heat and mechanical energy in the body of an organism. The suns light energy is converted to chem energy by plants during photosynthesis. When an animal consumes a plant, the chem energy in the plant is converted to heat and mechanical energy during respiration. ?

Law of Conservation of Energy Energy cannot be created or destroyed. The total amount of energy in a closed system is always the same. The energy in energy conversions is always conserved!! A closed system is a group of objects that transfer energy only to each other.

Where does energy go?? If energy is conserved then why do we have to be pulled back up the rollercoaster? Friction: force that opposes motion. Energy must be used to overcome this force.

No Conversion without Thermal Energy Any time one form of energy is converted into another form, some of the original energy always gets converted into thermal energy. Machines will never be 100% efficient. Thermal energy is not useful energy Energy efficiency

How Do Organisms Sense Energy? The noise of a cheering crowd can be deafening! The light from the sun can be blinding! The heat from boiling oil can be incredibly painful! Important to be able to sense all this energy!!!

Energy is all around us! Energy in its many forms, surround us. Organisms need various ways to sense the energy that surrounds them. Plants sense light energy and grow towards it. Snakes pit organs sense thermal energy from prey. Worms can feel vibrations in the earth. Other examples?? Dogs ears can sense sounds that humans cannot hear.

Assistance for sensing energy Engineers have developed devices to help us sense various forms of energy. The telescope is a device to help us sense light. Examples? Much of what we have learned about space came from the assistance of a telescope. Seismographs sense energy released during earthquakes Eyeglasses focus light energy Hearing aids amplify sound energy