All matter is made of moving particles I. Kinetic Theory of matter all particles in matter are constantly in motion a. Kinetic Energy is motion energy b. Therefore all particles in solids, liquids and gases have kinetic energy. 1
C. Temperature is a measurement of the average kinetic energy of all the particles in a substance. D.The faster the particles are moving the more kinetic energy they have, and increase the temperature. E. All particles in a substance are moving but not at the same speed and the speed can change. (phase chages) 2
Temperature can be measured I. 3 temperature scales: Celsius ( 0 C), Fahrenheit ( 0 F), and Kelvin (K) II. Absolute zero 0 K, and 273.15 0 C, is the temperature where there is no particle movement. III. Thermometers measure temperature: Alcohol expands when heated (liquid moves up the tube as it expands) and contracts when cooled (liquid moves down the tube as it contracts). 3
Heat is DIFFERENT from temperature I.Heat, temperature, and thermal energy are similar but not the same. II. Temperature: average kinetic energy of particles in a substance III. Heat: flow of energy from a warmer substance to a cooler substance. When energy is transferred the thermal energy of both substances changes IV. Thermal Energy: the total kinetic energy of particles in a substance. 4
Measuring Heat I. The most common units of heat measurement are the CALORIE and the JOULE. II. A calorie is the amount of ENERGY NEEDED TO RAISE THE TEMPERATURE OF 1 GRAM OF WATER 1 0 C III. A joule is the STANDARD SCIENTIFIC UNIT FOR MEASURING ENERGY. 5
Some Substances change temperature more easily than others I. SPECIFIC HEAT: the amount of energy that is required for 1gram of a substance to increase in temperature by 1 0 C. II. The more MASS an object has, more ENERGY is required to produce an increase in temperature (get hotter). 6
III. The more MASS an object has, more ENERGY must be released to produce a decrease in temperature (get cooler). Section 4.3: The Transfer of Energy as Heat can be Controlled 7
Energy moves as heat in 3 ways I. Conduction: ENERGY TRANSFERRED THROUGH PHYSICAL CONTACT (OBJECTS MUST BE TOUCHING). Particles of a warmer object collide with particles of a cooler object and some of their energy is transferred to the cooler object. 8
II. CONVECTION: a. Only occurs in LIQUIDS and GASES b. Caused by differences in densities, which are caused by differences in temperatures. i. Hotter=less dense Colder = more dense C. LESS dense liquids and gasses will FLOAT while MORE dense liquids and gasses SINK to the bottom; creating a convection current. 9
D. Cycles of convection cause the CURRENTS in the ocean, and WINDS in the atmosphere. Sea breeze Land breeze. III. Radiation: ENERGY THAT TRAVELS AS ELECTROMAGNETIC WAVES 10
A. All objects radiate at least a small amount of energy B. Electromagnetic waves: visible light, x rays, microwaves, radio waves, gamma rays, ultra violet rays. C. Unlike conduction or convection, radiation can move through empty space (the universe, or a vacuum). 11
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Different materials are used to control the transfer of energy. I. CONDCUTORS are objects that transfer energy easily. For example: metals (copper, iron, magnesium etc..) II. INSULATORS are objects that do not transfer energy easily. For example: wood, paper, plastic foam, anything with lots of trapped air 13