Thermal Energy
Heat Energy transfer occurs when two objects are at different temperatures Energy flows naturally from to . Energy transfers until the two objects are at the same temperature
Kinetic Energy Molecular Theory Matter is made up of particles. Particles are always in motion. bodies have particles that move faster than cool bodies, therefore they have higher energy than cool bodies.
Thermal Energy - Sum of KE and PE of the particles that make up an object. bodies have more thermal energy than a cool body. bodies have more KE and PE than cool bodies. Total amount of energy in body varies directly with the number of particles in the body.
Three Ways to Transfer Heat Conduction- transfer by contact (occurs in solids) 2. Convection – transfer of heat by movement of particles due to a difference in temperature. (occurs in liquids and gases) 3.Radiation – transfer of heat by electromagnetic waves. (occurs from the Sun to the Earth)
Temperature Temperature is a quantity that measures the average Kinetic energy of the particles independent of the size of the body. Ex. 1 kg of steel at 50oC and 2 kg of steel at 50oC Are they the same temp? Do they have the same KE of the particles? Total amount of KE of the particles?
Specific Heat Specific heat is a physical property of matter. All matter has a temperature associated with it. The specific heat is the amount of heat per unit of mass required to raise the temperature by one degree Celsius.
heat added = mass X specific heat X change in temperature The relationship between heat and temperature change can be expressed by: Q = m X c X ∆T heat added = mass X specific heat X change in temperature This relationship does NOT apply if a phase change is encountered, because the heat added or removed during a phase change does not change the temperature. Water has a specific heat of 1 calorie/gram °C = 4.186 joule/gram °C which is higher than any other common substance.
Heating Curve of Water
47. Heat convection occurs in gases and liquids 47. Heat convection occurs in gases and liquids. Heat convection does not occur in solids because solids are unable to — a. absorb heat by vibrating b. transfer heat by fluid motion c. emit radiation by reflecting light d. exchange heat by direct contact
47. Heat convection occurs in gases and liquids 47. Heat convection occurs in gases and liquids. Heat convection does not occur in solids because solids are unable to — b. transfer heat by fluid motion
50. In which container is the substance unable to transfer heat by convection? a. c. b. d.
50. In which container is the substance unable to transfer heat by convection? d.
51. Container P and Container Q each were filled with 0 51. Container P and Container Q each were filled with 0.5 liter of water. The water was heated to 90C. The table shows the temperatures after both containers were allowed to cool for 3 minutes. Compared to Container Q, Container P is a better — a. conductor c. radiator b. absorber d. insulator
51. Container P and Container Q each were filled with 0 51. Container P and Container Q each were filled with 0.5 liter of water. The water was heated to 90C. The table shows the temperatures after both containers were allowed to cool for 3 minutes. Compared to Container Q, Container P is a better — d. insulator
52. The transfer of heat by the movement of air currents in Earth’s atmosphere is an example of — a. conduction c. radiation b. convection d. fusion
52. The transfer of heat by the movement of air currents in Earth’s atmosphere is an example of — b. convection