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Chapter 1 Review

Chapter 1 Review. Heat, Energy, and Temperature. Chapter 1 review:. It turns out that a long time ago people thought heat was a fluid, made of atoms, like air or water . They thought it had weight and mass and was a “Thing” . They called this substance “caloric” .

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Chapter 1 Review

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  1. Chapter 1 Review Heat, Energy, and Temperature

  2. Chapter 1 review: • It turns out that a long time ago people thought heat was a fluid, made of atoms, like air or water . They thought it had weight and mass and was a “Thing”. They called this substance “caloric”. • But, it turns out that heat is NOT a thing, not made of atoms, not a substance at all. But the name stuck…heat was caloric. • So when we talk about calories we are talking about energy today and the amount of energy we are taking in to our body. We must USE that energy we have taken in OR our bodies will convert it to the storage form of energy…FAT. • Fat is simply the body’s way of saying…don’t want to use that energy now? OK. I will save it for you for later. Don’t worry about me……I have LOTS of ENERGY!!

  3. Chapter 2 Measuring Temperature

  4. Chapter 2: Remember there is a difference between heat and temperature…. HEAT TEMPERATURE • Heat is energy (thermal energy), it can do work • is the total amount of energy of the particles in an object. • Heat is measured with an instrument called a calorimeter • Heat is measured in Joules • Temperature is a man-made scale indicating whether heat is going into the system, temperature rising or is heat leaving the system, temperature declining • defined as the average kinetic energy of the particles of an object. • Temperature is measured with a thermometer • Temperature is measured in degrees

  5. Think About This? A thimble of water at 100oC and a bathtub full of water at 100oC. Which is warmer (temperature)? Which has more thermal energy? • The temperature is the same but the total amount of energy is different. The bathtub has more energy…….but why? • Because there is more water in the tub…..more MASS!! • MORE MASS = GREATER ENERGY

  6. Chapter 2: Measuring Temperature • Early man only had two ways to tell themselves how hot or cold something was. • They had to use their sense of…. • TOUCH (feel the temp. of an object) • SIGHT (color of material giving off heat) Me wonder if that hot or cold?

  7. BIG PROBLEM!!! Me wonder if someone can help? That not accurate! That not reliable!

  8. Chapter 2: The Scientists • Galileo (1564 – 1642) • Invented the first thermometer around 1600 • It was called an air thermometer • Only told if the air was getting warmer or colder • Was not very accurate….no scales to go by

  9. Gabriel Fahrenheit (1686–1736) • made the first reliable mercury thermometer in 1724 • The temperature scale he originated is named after him – FAHRENHEIT Degrees • In the briefest terms, Fahrenheit took a glass tube and graduated it…made marks, 1,2,3 etc. He used water and mercury. • We often do use water as our standard for things, it is cheap and plentiful and easy to get. • He froze some water and the mercury in the tube dropped to the mark he had made…32 degrees. When water boiled the mercury in the tube rose to 212 degrees.

  10. Anders Celsius (1701–1744) • When Celsius investigated the subject of temperature he did something a little differently. • He did not mark off the glass tube. He simply put it into frozen water and where the mercury landed he called that 0 degrees. • When water was boiling and the mercury rose and leveled off he called that 100 degrees. • Used most around the world today to tell temperature.

  11. William Thomson, a.k.a. - Lord Kelvin (1824–1907) • in science we use a third thermometer when dealing with extreme temperatures. • Lord Kelvin wondered, what would happen if there was a condition of NO HEAT. At “absolute zero” what would the conditions be? • At zero Kelvin, at absolute zero, all motion would cease • since temperature is an indirect measure of the motion (energy) of molecules, if there was no heat there would be no motion and thus no temperature

  12. We can convert from one temperature to another via these equations…. F = (1.8 x C) + 32 K = C + 273 C = (F – 32) ÷ 1.8

  13. Chapter 2: Interesting Facts • Are there any conditions under which boiling and freezing points can change? • As a matter of fact, there are two conditions that can affect boiling and freezing points… • Pressure • High pressure can cause ice to melt below 0 oC • Ex. – weight of glaciers (move glaciers move despite being frozen • Low pressure enables water to boil at a temperature below 100 oC • Ex. - On top of Mt. Everest, water boils at 69 oC • Impurities • Matter and materials add to a substance can also affect freezing and boiling points • Ex. – salt to icy roads

  14. Chapter 2: More Interesting Facts • Coldest Temp in Canada and North America: • Snag, Yukon ……. -62.8 oCon Feb. 3, 1947 • Warmest Temp in Canada: • Midale and Yellowgrass, Sask……. 45 oCon July 5, 1937 • Warmest Temp in North America: • Death Valley, California, USA……56.7 oCon July 10, 1913 • Coldest Temp in the World: • Vostok Station, Antarctica….. -89.2 oCJuly 21, 1983 • Warmest temp in the World: • Al 'Aziziyah, Libya………57.8 oCon Sept. 13, 1922

  15. Chapter 2: Other Ways to Measure • Sometimes it is necessary to record temperatures that normal thermometers cannot handle or were not designed for. • Thermometers that are used for measurements have 3 basic parts… • Sensor – a material affected by change • Signal – provides information about the temp. • Responder – indicates the data with a mechanism using the signal

  16. Some different types of temperature measuring devices are… • Thermocouple • Two wires of different metals are used • When heat is applied to one end an electric current is produced…….amount of current depends on the temperature • Used to measure large temp ranges…up to 2300 oC !! • Cannot measure low temperature accurately

  17. Bimetallic Strip • Two wires of different metals are fused together • These metals will expand and contract at different temps • Used in clocks, thermostats, electrical devices, etc LOOK!!!! Can you describe what is happening here?

  18. Recording Thermometer • Records temperature change over a period of time • Uses a bimetallic strip • Very similar to a seismograph

  19. Infrared (IR) Thermogram • Records the IR of an object • The IR heat signature is displayed through a colored image • Color indicates the temperature

  20. Volcanic Lava: • Ranges from 700 oC to 1600 oC • Depends on the depth of the magma before eruption

  21. Liquid Nitrogen: • Boils at -196 oC • Freezes at -210 oC http://www.youtube.com/watch?v=5j02WUaIF1E&safe=active

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