Lesson 2.1 -
What is Energy?
What is Energy?
True or False: Chemical energy is a type of kinetic energy.
False: it is potential energy stored in the chemical bonds of an object.
True or False: Kinetic energy can transform to potential energy and back again multiple times.
True
Water freezes at ____degrees C and boils at _______ degrees C.
0 degrees/ 100 degrees
Which state of matter has definite shape and volume?
Solids
Energy is...
the ability to do work or cause change
Friction transforms some kinetic energy into
thermal energy
Describe the difference between a conductor and an insulator.
A conductor allows heat to move easily throughout the object (metal pan or copper wire) while an insulator slows or blocks the movement of heat (wooden spoon or a rubber mitt).
True or False: Energy can only be 100% efficient in solar-powered machines.
False
Energy can not be created nor destroyed; only transformed from one form of energy to another.
Compare the energy of a roller coaster at the top of a hill versus at the bottom of the hill.
The roller coaster at the top of the hill has the greatest gravitational potential energy while it has the greatest kinetic energy at the bottom of the hill.
Name the three types of heat transfer.
Conduction, convection and radiation
What scale uses absolute zero? What is absolute zero?
Kelvin Scale - it is the coldest temperature where matter physically stops motion.
What are the two types of potential energy? Give an example of each.
Gravitational Potential Energy - A book on a shelf, a person standing at the top of a hill, etc.
Elastic Potential Energy - A bow and arrow, a stretched rubber band, etc.
Name the energy transformation that occurs when you turn on a hair dryer. (4 transformations)
Electrical energy -> mechanical energy -> Thermal Energy + Sound Energy
Is there more thermal energy in a pool filled with 75 degree water or in a coffee cup with 125 degree coffee? Explain why.
In the pool of 75 degree water because thermal energy is the temperature of the object + how much matter is in the object. Even though the temperature is less in the pool of water, the amount of matter is much greater than the cup of coffee so it has more thermal energy.
Name two ways we can increase potential energy.
Increase the height of the object (gravitational potential energy) or increase the pressure on an object being stretched (elastic potential energy).
Name 5 types of energy we discussed in class. Give an example of each.
Mechanical energy, Thermal Energy, Radiant Energy, Nuclear Energy, Chemical Energy, Electrical Energy
What is the energy efficiency formula?
(Useful energy output / total energy input) * 100 = Energy efficiency (%)
Describe a convection current.
A convection current is a transfer of heat in a fluid (liquid or a gas). A heated fluid's particles begin to move faster, spreading apart, causing it to lose density and rise. As it rises, it begins to cool and condense, making the fluid more dense which makes it sink.
Name an example of each type of heat transfer.
Conduction - Touching a hot stove, sitting on a warm bench, holding hands
Convection- Boiling water, water cycle
Radiation - The sun, the heat felt from a fire, a space heater