Physical Science Test Chapter 14
Convection Current
Any movement of matter that results from differences in density; may be vertical, circular, or cyclical
Explain the difference between total and average molecular kinetic energy of a gas contained in a box.
As an average K.E. of the particles increases, the object's temperature increases. Total Kinetic Energy is the sum of energy.
If you wear dark clothing on a sunny day, the clothing will become hot after a while. Explain why by using the concept of radiation.
By radiation, the darker shirt absorbs more heat.
The type of energy transfer that takes place between objects in direct contact is...
Conduction
True or False: Desert Jackrabbits have large ears to keep them cool.
True, their ears radiate heat to keep them cool.
What is 100 K on the Celsius scale?
-173 degrees Celsius
The temperature at which particles of a substance would have no kinetic energy is...
0 Kelvin
What is -30 degrees C on the Kelvin scale
243 K
What is 9 degrees F on the Celsius scale?
35 degrees C
What is 16 degrees C of the Farenheit scale?
60.8 degrees F
Heat Engine
A Machine that transforms heat into mechanical energy or work.
Explain why a ceramic bowl will keep oatmeal hot longer than a stainless steel bowl.
A ceramic bowl is a good conductor of heat, and will put its energy towards the oatmeal, where as stainless steel will put its energy to the outsides of the bowl.
Explain why placing a damp towel over a fan will increase its ability to cool a room.
A damp towel will keep a room cool, because the towel will absorb heat.
Explain how a diesel engine is different from other internal combustion engines.
A diesel engine burns fuel/diesel by compressed air. Compression on diesel is higher than other internal combustion engines.
Explain how a liquid thermometer measure temperature.
A liquid thermometer expands when it's hot and becomes smaller in size when it's cold.
Entropy
A measure of the randomness or disorder of a system
What is a poor conductor of energy.
Air
True or False: Opening the door of the refrigerator will cool the kitchen.
False, because the hot air will come to the refrigerator, and the hot air will go to the refrigerator, making it warmer.
Explain why steam (gas) has a lower specific heat that water (liquid).
Gas has a lower specific heat than water, because all of the particles are flying around.
Predict what will happen if a block of hot iron is placed in a glass of cool water.
If a block is of hot iron is placed in a glass of cold water, the temperature of the iron will decrease, and the temperature of the water will increase.
Temperature is proportional to the average kinetic energy of particles in an object. Thus, an increase in temperature results in a(n)...
Increase in Average Kinetic Energy
Describe a method of insulation that can completely eliminate heat loss by conduction.
Keeping an air-filled space can completely eliminate it, because there is no conduction.
A material made of ___ would be a very good conductor of energy.
Metal
Use the differences between a conductor and an insulator and the concept of specific heat to explain whether you would rather drink a hot beverage from a metal cup or from a china cup.
Metal is a conductor with a low specific heat, where as the fine china has a high specific heat.
A type of energy transfer that can occur in empty space is...
Radiation
Explain which method of heat transfer can take place if two objects at different temperatures are places without each other in a vaccum.
Radiation will be the best method of heat transfer, because they do not touch.
Evaluate the following newspaper headline. Is it realistic? Explain. Scientists Create a Thermometer to Measure Temperatures Below 0 Kelvin.
That title is not realistic, because it can't be below absolute zero.
Radiation
The Energy Transferred as electromagnetic waves, such as visible light and infrared waves.
Thermal Conduction
The Transfer of energy as heath through a material
Second Law of Thermodynamics
The energy transferred as heat always moves from an object at a higher temperature to an object at a lower temperature.
Temperature in Terms of Kinetic Energy.
The temperature of a substance is proportional to the average Kinetic Energy of the substance's particles.
Determine which is the best type of skillet. Some people prefer a heavy cast iron skillet while others prefer a thin stainless steel one.
The heavy cast iron skilled because it has better insulation that a thin stainless steel one.
Explain why a metal door should not be built to fit tightly to the frame of a door, especially in a region where the weather gets hot.
The metal door will increase, because the particles will move around more, expanding the door, and then you can't open it.
convection
The movement of matter due to differences in density that are caused by temperature variations
Specific Heat
The quantity of heat required to raise a unit mass of homogenous material 1 K or 1 Degree Celsius in a specified way given constant pressure and volume.
Describe the method of heat transfer involved when you mix hot water with cold water to make lukewarm water.
There is thermal conduction, because the hot water is moving to cold water by contact.
First Law of Thermodynamics
Total energy used in any process is conserved, whether that energy is transferred as a result of work, heat, or both.
True or False: Shivering when you are cold actually warms you up.
True, because you are moving and not sitting still.
The amount of usable energy decreases...
Whenever energy is transferred
