August 24, 2017 Warm-Up: Complete the specific heat formula sheet – you may use a calculator Step 1 – determine what you know & for which variable you are solving Step 2 – plug your known quantities into the correct formula Step 3 – solve the equation HOMEWORK: Quiz tomorrow! Review chapter 10. Study Quizlet flashcards. USA Test Prep due Friday.
Quiz tomorrow – know the following: Thermal energy, temperature, and heat transfer (definitions, differences, examples) Convection, conduction, radiation (definitions, differences, examples) Conductors & insulators (definitions, differences examples) Specific heat – how to use the formula and solve problems
What is heat? What is temperature?
Thermal Energy, Temperature and Heat Transfer The terms heat and temperature are often confused by people… Thermal energy is the TOTAL kinetic energy of the particles that make up a substance Temperature is a measure of the average kinetic energy in an object Heat transfer is how thermal energy moves from an object of higher temperature to an object of lower temperature
Remember… Heat likes to go from high to low until it has nowhere else to go! We call that EQUILIBRIUM
…something which has a higher temperature than another does not necessarily contain more heat energy…
Coffee Pot or the North Sea Which is hotter? (temperature) Which contains more energy? (heat) You need to be able to explain your answer http://www.brainpop.com/science/energy/heat/
Iceberg or a glass of water Which is hotter? (temperature) Which contains more energy? (heat) You must be prepared to explain your answer http://www.brainpop.com/science/energy/temperature/
Temperature Temperature is a measure of the average kinetic energy of the particles of a substance. Fahrenheit, Celsius, and Kelvin are three temperature scales. Absolute zero (0 K, or –273ºC) is the lowest possible temperature. Thermal expansion is the increase in volume of a substance due to an increase in temperature.
Heat Heat is energy transferred between objects that are at different temperatures. Thermal energy is the total kinetic energy of the particles that make up a substance. Thermal energy will always be transferred from higher to lower temperature. Transfer of thermal energy ends when two objects that are in contact are at the same temperature.
Conductors and Insulators Thermal conductors allow heat to transfer easily Examples include metals such as iron, copper, or aluminum Thermal insulators do not allow heat to transfer easily Examples include plastic, wood, and glass
Heat Transfer Conduction, convection, and radiation are three ways thermal energy is transferred.
Penguin Convection!
Specific Heat Specific heat is the amount of energy needed to change the temperature of 1 kg of a substance by 1ºC. Energy transferred by heat cannot be measured directly. It must be calculated using specific heat, mass, and change in temperature.
Specific Heat Formula Q = Energy in Joules M = Mass in grams C = Specific Heat Capacity in Joules/goC T = Temperature Change in OC
Example: How much energy is needed to heat a cup of water to make tea? Heat (J) = 4,184 J/kgOC x 0.2 kg x 55OC 4,184 x 0.2 x 55 = 46,024 Joules Kilograms and Celsius degrees cancel out!
August 24, 2017 Warm-Up: Complete the worksheet HOMEWORK: Quiz tomorrow! Read chapter 3, section 3. USA Test Prep due Friday.
States of Matter Poster Four boxes for the 4 states of matter: solid, liquid, gas, plasma Draw arrows to and from each box for phase changes In each box have a 2-D model of the particle arrangement (a picture) Describe shape, volume, energy, and spacing of molecule