Energy in Earth Processes Earth Science Mr. Cloud
Energy Energy: is the capacity or ability to do work. The capacity to make a change. Energy comes in many forms: Chemical Energy Radiant Energy Solar Energy Thermal Energy Mechanical Energy Nuclear Energy Electrical Energy Energy is expressed in units of work Joules (kJ,J) or Calories (kcal, cal)
Energy Thermodynamics: the study of energy and its transformation 3
Energy 1st Law of Thermodynamics – Law of Conservation of Total Energy energy can change forms, but is not created or destroyed Where does the energy to light your home come from? Using you knowledge of the 1st Law of Thermodynamics, arrange the following forms of energy in the proper order. Discuss how one form transforms into another.
Potential vs. Kinetic Energy Stored Energy Energy of Motion 5
1st Law of Thermodynamics Forms of Energy: Kinetic energy Potential energy electrical energy mechanical energy heat energy electromagnetic energy
Temperature v. Heat What is the difference between temperature and heat? Use your review books to figure it out. 2009 Edition: Topic 5
Temperature A measure of the average kinetic energy of the particles of a body of matter. Thermometer: instrument that measures temperature How does temperature relate to the amount and type of electromagnetic energy radiated from a body of matter? Three temperature scales: Celsius, Kelvin, Fahrenheit
Heat Energy Transfer of energy from regions of high temperature to areas of lower temperature. SOURCE SINK Low Temperature ! High Temperature!
Heat Calculation: Enthalpy Q = m . c . Δ T specific heat (J/g . oC) change in temperature (oC) Heat (Joules) Mass (g)
Heat Calculation A student uses a Bunsen Burner to heat a test tube filled with 25 g of liquid water. The temperature of the water increases from 10 oC to 15 oC. How many joules were absorbed by the water? 25g . 4.18 J/g. oC . 5 oC 522.5 J
How many joules were released from the sample? Heat Calculation A student cools a 36g sample of granite from 200 oC to 125 oC. How many joules were released from the sample? 2133 J
Types of Energy Transfer Conduction Convection Radiation
Conduction: ‘Touch’ Energy transfer by molecular or atomic collision Metals are the best conductors of heat energy
Convection: ‘Density’ Heat transfer driven by differences in density Heat transfer within fluids
Radiation Energy transfer via electromagnetic waves No medium required Sunlight radiates towards Earth at various wavelengths