Presentation on theme: "Energy!Energy! The ability to do work. Types of energy Nuclear Mechanical –Potential –Kinetic Electromagnetic (Solar/Light) Electrical Chemical Thermal."— Presentation transcript:
Energy!Energy! The ability to do work
Types of energy Nuclear Mechanical –Potential –Kinetic Electromagnetic (Solar/Light) Electrical Chemical Thermal (Heat)
Nuclear Nuclear energy is created from reactions in the nucleus of the atom:
Nuclear –Fusion – Atoms combining into one atom –Fission – An atom splitting apart –Radioactivity - an atom decaying (losing part of its nucleus)
Mechanical Energy Energy relating to the motion or position of an object Mechanical Energy has two forms: Kinetic & Potential
Potential and Kinetic Potential: stored energy –It has the potential to do work, but it is not in the action of doing any work. Kinetic: energy of motion –Energy that is actively doing work.
Examples of Mechanical Energy : Sound – molecules of air hitting your ear drum causing it to vibrate. Hydroelectric – Water pressure causing a turbine to spin Friction – rubbing objects together creating heat. Wind – Molecules of air moving and colliding with objects.
Electromagnetic (Light) Waves of energy that travel through space from the sun and stars Different wavelengths carry different amounts of energy We only see a small portion of the spectrum
Electrical Movement or flow of electrons –Electrons carry a charge
Chemical Energy stored in the form of chemical bonds
Special type of chemical reaction: Combustion! Burning natural gas: CH 4 + O 2 CO 2 + H 2 O Burning propane: C 3 H 8 + O 2 CO 2 + H 2 0 Burning gasoline: C 8 H 18 + O 2 CO 2 + H 2 0 Hydrocarbon + oxygen carbon dioxide + water
Endothermic and Exothermic Reactions Breaking bonds between atoms uses energy– this is an Endothermic process Making bonds between atoms releases energy– this is an Exothermic process. In a chemical reaction, bonds are both made and broken. Sometimes the net result will be endothermic, and sometimes it will be exothermic.
Most Chemical reactions need something to get started – Activation Energy
Heat (thermal) Movements of atoms in a substance
Heat (thermal) Heat vs. Temperature –Temperature is the average speed of the molecules. The faster the molecules move, the higher their temperature. –Heat is the energy that flows due to temperature differences. –The Amount of the substance will affect heat but not temperature.
Heat (thermal) 40 degrees Celcius 90 degrees Celcius Which has a higher temperature? Which has more heat? (Hint – which will warm you up more?)
Heat transfer Conduction –Heat transferred through direct contact between substances Convection –Heat transferred by currents moving in a gas or liquid Radiation –Heat transferred by electromagnetic waves
Energy Transfer Energy is constantly converting from one form to another
Energy Transfer Law of Conservation of Energy: Energy is neither created nor destroyed – it is converted. Nothing is 100% efficient
Here electrical energy is being converted to: ____________ But what other conversions are happening?
Here electrical energy is being converted to: ________________ But what other conversions are happening?