# Heat PowerPoint

29 de Jan de 2014
1 de 24

### Heat PowerPoint

• 2. HEAT   Heat is the total kinetic (moving) energy of all molecules.   Depends on the mass and energy of the particles!
• 3. If you have a cup of water the same temperature as the ocean, which has more heat energy?
• 4. How does heat flow?  Heat flows from hot to cold until the heat is balanced which we call equilibrium.
• 5. A metal cup containing water at 100F is placed in an aquarium containing water at 80F:   A) Which way will heat flow? Why?   B) When will the flow of heat stop?   C) What is it called when heat no longer flows?
• 6. How is heat measured?         It is measured in calories, joules, or BTUs A calorie is the amount of heat used to raise the temperature of one gram of water one degree Celsius. One calorie = 4 joules One Calorie (food)=1000 calories (4,000 J)
• 7. What is the difference between heat and temperature?   Heat is the total amount of kinetic energy available.   Temperature is a relative measure of the speed of the particles.   Temperature is measured in degrees.   Temperature and heat are not the same!!!!
• 8. What happens when a substance is heated?  The speed of the particles increases which causes the space between the particles to increase
• 9. How does heat affect volume?   Volume increases with more heat. More heat means that the molecules are moving faster (more kinetic energy), therefore they bump into one another and spread out.   Less heat means less volume!
• 10. What effect does heat have on density?   When a substance is heated, it expands, volume increases therefore it becomes less dense.
• 11. Temperature Scales  The 2 main temperature scales are Celsius and Fahrenheit.  Boiling point is 100 C & 212 F  Freezing is 0 C & 32 F
• 12. Kelvin Scale A third temperature scale used mainly for scientific purposes, where absolute 0 is the coldest possible temperature. It starts at 0 (which is absolute 0) Boiling 373 Freezing 273
• 13. Absolute Zero  Absolute zero is the temperature where there is an absence of heat. There is no motion of molecules. It has not been reached in real life or in a lab, but scientists have gotten very close.
• 14. ABSOLUTE ZERO  Absolute Zero = -460 F  Absolute Zero = -273 C  Dry Ice = -110 F  Coldest Place on Earth = -70 F
• 15. What is speciﬁc heat?   The amount of energy needed to raise the temperature of 1 kg of a substance by 1 degree Celsius.   The ability of a substance to absorb heat.   This property can help identify substances.
• 16. Example of Speciﬁc Heat   How much energy does it take to raise the temperature of 2 kilograms of water by 3°C (speciﬁc heat of water is 4,184 J/kg°C)   Solution: 2 kilograms x 3°C = 6 kg°C   4,184 J/ kg°C x 6 kg°C = 25,104 J
• 17. What are the 3 states of matter? Solid-has a defined volume and shape. Liquid-defined volume, takes the shape of its container. Gas-no defined shape or volume.
• 19. What is heat of fusion? The amount of energy used to melt one gram of a substance without changing its temperature.
• 20. What is heat of vaporization?  The phase change when a liquid becomes a gas.  The energy needed for one gram of a liquid to become a gas without changing the temperature.  The particles gain enough energy to permit them to escape the surface of the liquid and become a gas.
• 21. STOP HERE TAKE THIS QUIZ. SCORES WILL BE COUNTED. LOOK BACK THROUGH THE POWERPOINT AS NEEDED!  http://makeaquiz.net/eIAwte
• 22. CONDUCTION  Conduction is the direct transfer of heat.  Does conduction happen better in solids, liquids, or gases? Conduction works best through solids!
• 23. CONVECTION  Convection is when warmer less dense material rises and is replaced by cooler, more dense material. It then becomes heated and rises creating a current (or repeating cycle!).
• 24. RADIATION  Radiation involves the transfer of heat through the air or a vacuum! ALL objects radiate heat!