2 Types of energy Nuclear Mechanical Electromagnetic (Solar/Light) PotentialKineticElectromagnetic (Solar/Light)ElectricalChemicalThermal (Heat)
3 NuclearNuclear energy is created from reactions in the nucleus of the atom:
4 Nuclear Fusion – Atoms combining into one atom Fission – An atom splitting apartRadioactivity - an atom decaying (losing part of its nucleus)
5 Energy 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
6 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 motionEnergy that is actively doing work.
7 Examples 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.
8 Electromagnetic (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
9 ElectricalMovement or flow of electronsElectrons carry a charge
12 Special 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
13 Endothermic 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.
14 Most Chemical reactions need something to get started – Activation Energy
15 Heat (thermal)Movements of atoms in a substance
16 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.
17 Heat (thermal) 90 degrees Celcius 40 degrees Celcius Which has a higher temperature?Which has more heat? (Hint – which will warm you up more?)
18 Heat transfer Conduction Convection Radiation Heat transferred through direct contact between substancesConvectionHeat transferred by currents moving in a gas or liquidRadiationHeat transferred by electromagnetic waves