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HEAT AND TEMPERATURE Temperature  quantity that tells “ how warm or how cold” a body is with respect to some standard scale.  It is the average kinetic.

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Presentation on theme: "HEAT AND TEMPERATURE Temperature  quantity that tells “ how warm or how cold” a body is with respect to some standard scale.  It is the average kinetic."— Presentation transcript:

1 HEAT AND TEMPERATURE Temperature  quantity that tells “ how warm or how cold” a body is with respect to some standard scale.  It is the average kinetic energy of all the particles in an object.  Particles at a high temperature have a great amount of KE, particles with low temperature have less KE.

2  Higher temperatures mean that the molecules are moving, vibrating and rotating with more energy.

3 Heat  a form of energy transferred from one body to another body because of a temperature difference between bodies. Heat vs Temperature  Heat is energy while temperature is not.  Heat can be transferred from one body to another while temperature cannot be transferred  Heat depends on the size or type of object while temperaturedoes not.

4 Temperature Scales & thermometers In the early years of the eighteenth century, Gabriel Fahrenheit, German scientist (1686-1736) created the Fahrenheit scale. He set the freezing point of water at 32 & the boiling point at 212 . These two points formed the anchors for his scale. He invented the alcohol thermometer in 1709, and the mercury thermometer in 1714.

5 Later in that century, around 1743, Anders Celsius, Swedish astronomer (1701-1744) invented the Celsius scale. He determined the freezing temperature for pure water to be 0  and the boiling temperature 100 . The Celsius scale is known as a Universal System Unit Celsius temperature scale is also referred to as the "centigrade" scale. It has 100 degrees between the freezing point (0 C) and boiling point (100 C)

6 Lord William T. Kelvin said: “There is a limit to how cold something can be”. The Kelvin scale is designed to go to zero at this minimum temperature. At a temperature of Absolute Zero there is no motion and no heat. Absolute zero is where all atomic and molecular motion stops and is the lowest temperature possible. Absolute Zero occurs at 0 degrees Kelvin or -273.15 degrees Celsius or at -460 degrees Fahrenheit. All objects do not have heat when they have a temperature of absolute zero.

7 Anchor Points Celsius (  C )Fahrenheit (  F ) Kelvin ( K ) Freezing pt. of water Boiling pt. of water Normal Body Temp. Room Temp. 0  C 100  C 37  C 20  C 32  F 212  F 98.6  F 68  F 273K 373K 310K 293K Comparison of Temperature Scales

8 THERMOMETERS Typical thermometer Digital thermometer http://images.search.yahoo.com/search/images?_adv_prop=images&imgsz=all&imgc=&vf=all&va=thermo meter&fr=FP-tab-web-t500&ei=UTF-8

9 Conversion of Temperature Scales Converting C  F F = 9/5 C + 32 Converting F  C C = 5/9 (F – 32 ) Converting C  K K = C + 273 Converting K  C C = K – 273

10 1.Example 1: The body temperature of a child is 104F. Will a nurse give him a medicine for fever? Example 2: The temperature reading during one summer day is 27C, how much is this in F?

11 Example 4: The innermost layer of the earth is believed to be approximately 1000 C, how much is this in K? Example 3: A nurse in a hospital measured the body temperature of a child patient. She got 313 K, would the nurse give the child a sponge bath? Conversion of Temperature Scales

12 What Is Fever?  Fever occurs when the body's internal "thermostat" raises the body temperature above its normal level. The thermostat is found in the part of the brain called the hypothalamus.brain The hypothalamus knows what temperature your body should be (usually around 98.6  F, or about 37  C) and will send messages to your body to keep it that way.

13  Most people's body temperatures even change a little bit during the course of the day.  It's usually a little lower in the morning and a little higher in the evening and can fluctuate as kids run around, play, and exercise. Sometimes, though, the hypothalamus will "reset" the body to a higher temperature.

14 What causes fever?  Infection: Most fevers are caused by infection or other illness. Fever helps the body fight infections by stimulating natural defense mechanisms. Why does the hypothalamus tell the body to change to a new temperature? Researchers believe that turning up the heat is the body's way of fighting the germs that cause infections and making the body a less comfortable place for them.

15 What causes fever? Overdressing: Infants, especially newborns, may get fevers if they're over bundled or in a hot environment because they can't regulate their body temperature. Immunizations: Babies and children sometimes get a low- grade fever after getting vaccinated. Although teething may cause a slight rise in body temperature, it's probably not the cause if your baby's or toddler's temperature is higher than 100 degrees Fahrenheit (37.8 degrees Celsius). http://coolcosmos.ipac.caltech.edu/cosmic_classroom/light_lessons/thermal/index.html

16 EXERCISE: TEMPERATURE 1. The body temperature of an infant is 42C. Find the temperature in: a) F b) K 2. The temperature of the day is 33 C. Find the temperature in (a) K (b) F 3. The innermost layer of the earth has an approximate temperature of 1000 C. Find its equivalent in (a) F (b) K 4. The temperature of a boiling liquid is 175 F. Find its equivalent in: (a) C (b) K 5. The melting temperature of a solid is 140 F. Find its equivalent in: (a) C (b) K 6. The temperature of an adult patient is 110 F. Find its equivalent in: (a) C (b) K 7. The temperature of a substance is 300K. Find its equivalent in (a) F (b) C 8. The temperature scale of a star is 1273K. What is its equivalent on the C? 9. A Fahrenheit thermometer reads 68 F. What is its equivalent in Kelvin? 10. A patient has a fever. His temperature is 108 F. What is this in the C? #1 – 1, 4, 8 #2 – 2, 3, 9 #3 – 4, 7, 10 #4 – 5, 6, 8


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