2Types of energy Nuclear Mechanical Electromagnetic (Solar/Light) PotentialKineticElectromagnetic (Solar/Light)ElectricalChemicalThermal (Heat)
3NuclearNuclear energy is created from reactions in the nucleus of the atom:
4Nuclear Fusion – Atoms combining into one atom Fission – An atom splitting apartRadioactivity - an atom decaying (losing part of its nucleus)
5Energy relating to the motion or position of an object Mechanical EnergyEnergy relating to the motion or position of an objectMechanical Energy has two forms: Kinetic & Potential
6Potential 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 motionEnergy that is actively doing work.
7Examples of Mechanical Energy: Wind – Molecules of air moving and colliding with objects.Sound – molecules of air hitting your ear drum causing it to vibrate.Hydroelectric – Water pressure causing a turbine to spinFriction – rubbing objects together creating heat.
8Electromagnetic (Light) Waves of energy that travel through space from the sun and starsDifferent wavelengths carry different amounts of energyWe only see a small portion of the spectrum
9ElectricalMovement or flow of electronsElectrons carry a charge
12Special type of chemical reaction: Combustion! Hydrocarbon + oxygen carbon dioxide + waterBurning natural gas:CH4 + O2 CO2 + H2OBurning propane:C3H8 + O2 CO2 + H20Burning gasoline:C8H18 + O2 CO2 + H20
13Endothermic and Exothermic Reactions Breaking bonds between atoms uses energy– this is an Endothermic processMaking 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.
14Most Chemical reactions need something to get started – Activation Energy
16Heat (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.
17Heat (thermal) 90 degrees Celcius 40 degrees Celcius Which has a higher temperature?Which has more heat? (Hint – which will warm you up more?)
18Heat transfer Conduction Convection Radiation Heat transferred through direct contact between substancesConvectionHeat transferred by currents moving in a gas or liquidRadiationHeat transferred by electromagnetic waves