Physical Science Chapter 3
The process of heat transfer from one said object to another through direct contact (like when you touch a hot pan)
conservation of energy
The principle that energy is never created or destroyed, only changed from one form to another.
The process of heat transfer by molecular motioning fluids. As fast molecules mingle with slower molecules, they collide and energy is transferred from the faster molecules to the slower molecules. Occurs in fluids (liquids AND gases).
A substance that will flow; a liquid or a gas.
Energy that is being transferred as a result of temperature differences (from a warm body to a cooler one), by means of infrared radiation, thermal conduction, or convection
When energy is transferred from a warm object to a cooler one by means of infrared radiation, thermal conduction, or convection.
The sum of all the kinetic energies in a particle.
Einstein’s theory (1905) that mass and energy are different forms of the same thing, that amounts of mass and energy may each be expressed in terms of the other; Formula used to express this –
mechanical equivalent of heat
The theory that heat and kinetic energy are different forms of the same thing – energy, and may be converted from one for to the other.
Electromagnetic waves. In heat transfer, refers specifically to electromagnetic waves in the infrared region of the electromagnetic spectrum. (light and heat from the sun)
A state when two objects (or an object and its environment) are at the same temperature and there is no heat flow
A mechanical process whereby energy is transferred from one object to another by a force pushing through a certain distance
What is “caloric”?
a gas scientists used to think existed that would travel from hot objects to cold ones and vice versa
State the law of conservation of energy.
energy can be neither created nor destroyed, only change form
Make up three of your own examples, different from the ones in the text, that demonstrate the law of conservation of energy.
a roller coaster reaching the top of a hill and stopping, a frog jumping then stopping, and a steam powering a turbine
When friction is present on a moving object, how does this affect the amount and forms of energy present in a given situation?
it slows the object and heats it
Where does the energy come from in the fission reactors we use to produce electricity?
when an atom splits apart it makes smaller pieces, and energy is formed from the subtraction
What does mass-energy equivalence mean?
there is an equivalent amount of energy for all mass
Why is it incorrect to say that an object has heat in it?
heat means energy that is still in transit not temperature
What is thermal equilibrium?
when two objects are the same temp so no heat flows between them
How does conduction work?
when something is hot it vibrates, and in metal and other conductors, the material vibrates easily
How does convection work?
when a fluid is hot, the atoms in it are moving very fast, so when it comes in contact with something cold, the atoms begin to collide
Make up four examples of your own that illustrate one machine or person doing work on another.
digging a hole, lifting weights
If you press as hard as you can against a brick wall until you begin breathing hard and sweating, did you do any work on the wall? Explain your answer.
No work on the wall since the wall gained no energy. (For work to be done on something energy must be transferred.)
What are the three ways heat is transferred?
Infrared Radiation, Thermal Conduction, and Convection
Write a paragraph explaining how we can determine the surface temperature of an object by sensing the infrared radiation the object is emitting.
Consider again the glass of ice water in the previous question. Does the idea of thermal equilibrium apply at all here? Explain your answer.
Energy that is store and can be released by conversion into a different form of energy.
What are the contributions of Albert Einstein and Benjamin Thompson to the field of thermodynamics.
What are the 2 ways in which energy can be added to a system.
You can add energy to an object by adding heat to it or by doing work on it and you can’t tell which mechanism was used to give it that energy.
Explain how friction opposes motion and results in heat being released.
Friction is a force that acts in an opposite direction to movement resulting from the contact of two surfaces. It produces heat which is released into the environment.