Ashley Tisdale
8.2
Temperature, Thermal Energy, and Heat
Objective 1
1. Kelvin, degree Celsius, and degree Fahrenheit are the three temperature scales.
2. Thermal energy is all the energy an object has; kinetic, potential... THis is related to temperature which is the measure of the average kinetic energy something has. It is measured in scales Fahrenheit, Celsius and Kelvin. This is related to heat because heat is the energy.
3.Specific heat is the amount of energy needed to raise one gram of a substance by one degree Celsius.
4.When one object has contact with another object that has more kinetic energy or a higher temperature, then some of that energy goes into the system and starts to make the molecules of the first object move faster until eventually they will overcome their molecular force and become a liquid. This is how an ice cube melts in your hand.
5.Some objects get hot more quickly than others because they are smaller in size and volume.
Objective 2
1. A thermometer is a man made object that indicates the direction heat/energy flows.
2. They are all degrees on a thermometer, but they have different freezing an d melting points.
3. 5.0 degrees C equals 41 degrees Fahrenheit.
4. 860.00° Fahrenheit is 460.00° Celsius.
5. 209,000J is the specific heat required to raise 5 kg of water to 10 k.
Objective 3
1. The three different types of heat transfer are conduction, radiation and convection.
2. Heat moves from an objective with a high temperature to an object with a lower temperature.
3. Conduction is when atoms get warmer they start to move faster and collide with one another, conduction is the energy created by theses collisions. Insulation prevents heat transfer from happening so quickly and it keeps the heat inside and object.
4. It would work better as a conductor because it is a type of metal and is cool to the touch.
5. If I were camping on a mountain I would build a tent and make a fire. To get warmer first I would build a fire and heat transfer would occur between me and the fire because of radiation. After that I would go in my tent which would act as an insulator for me.
Objective 4
1.heat transfer causes matter to change state as it causes the temperature of an object to go up. This will result in it overcoming its molecular force and the object will then change to the next state of matter.
2. As thermal energy increases an object will overcome its molecular force and will change states.
3. When matter is changing state the temperature does not change because the energy being put in to it is used to change state, the temperature rises when the energy is being put into it and it is not changing state, so it can not go into that process but the object itself.
4. Heat transfer causes an object to melt.
5. You poke holes in a potato before baking it because potatoes are mostly water and when in the microwave with radiation the water turns to a gas, pushing on the outside of the potato.
Objective 5
1. In a heat engine heat is transfered from the source and then to the body of the engine. During this process the temperature is used between the hot and cold source.
2.An external combustion engine performs conduction as it heats up a separate object as its work. Internal combustion engines work by radiation as they are fueled by the production of heat and light. They are similar though because they both are heat engines that turn heat energy into mechanical energy.
3.Internal engines are used more often in society today though as they can supply a great deal of power simply and they are much lighter in their mass and weight.
4.The refrigerator uses the evaporation of aliquid to absorb heat.
5. Inside a refrigerator there is convection in the air and it would stop this.
Objective 6 is on the copy from my lab notebook.
Bonus: Farmers spray water on there crops before the temperature drops below freezing because the water will freeze and the ice will insulate the crop. The ice traps the heat on the inside of the crop and this latent heat is enough to keep the plant warm. And when the spraying and freezing stops the ice will go back to normal temperature so you have to continue to spray it.
Cites
- http://www.bristolaggie.mec.edu/school/Velozo/Chapter6.htm
- http://wiki.answers.com/Q/Why_does_water_have_a_high_and_specific_heat_capacity
- www.csun.edu/~plb17038/files/ppt/Heat%20and%20temperature.ppt
- http://walking.about.com/library/cal/uctemp.htm
- http://chemistry.about.com/library/weekly/bltempconvert.htm
- http://home.howstuffworks.com/thermos1.htm
- http://en.wikipedia.org/wiki/Thermal_insulation
- http://www.wordiq.com/definition/Internal_combustion_engine
- http://wiki.answers.com/Q/Why_does_the_temperature_of_matter_remain_the_same_while_the_matter_changes_state
