Warm Up: Copy this slide in notes How does heat Move? 3 Ways: 1. Conduction 2. Convection 3. Radiation
Conduction transfer of thermal energy by direct contact Example: 1. You touch a hot piece of metal 2. The hotplate touches the glass beaker Unfortunately for someone, after being touched, the heat will transfer from the iron to the hand. What are some other real-life examples where heat is transferred by conduction?
Conductors and Insulators substances that conduct thermal energy well Insulators substances that do not conduct thermal energy well they delay heat transfer What are some common conductors and insulators? Melting Blocks
Convection transfer of thermal energy through fluids (liquids or gases) by means of up and down movements called convection currents As the air gets heated by the flame, the particles move faster and spread out. This increases the volume of the air inside the balloon, which lowers the density. This decrease in density causes the balloon to rise. Sea and land breezes result from uneven heating of the Earth’s surface and the resulting convection currents. Explain how this happens.
Radiation transfer of thermal (radiant) energy as electromagnetic waves, such as visible light or infrared waves Travels through empty space. Example sun energy. Notice how the visible light from the sun travels through space and heats the Earth.
Plickers quiz
Take out your data from yesterday Make sure that you have calculated the change in energy of the water for each trial. Qwater=(Masswater)(Δtwater)(Specific heat water) This Q value is the amount of heat given to the water by the metal that you dropped in.
Now calculate the Specific heat of the metals Rearrange the formula to solve for specific heat Q=(m)(Δt)(C) Now calculate the specific heat of your mystery metals. (Be carful!!!) Which masses and temps are you using?
Take a few minutes to finish your calculations Work neatly and show all work. Remember units.