chapter 4 – energy. energy energy—the ability to cause change and the ability to do work 9 main...
TRANSCRIPT
Chapter 4 – ENERGY
EnergyEnergy—The ability to cause change and the
ability to do WORK
9 Main forms of energy:
– 1. Electrical: energy due to moving electrons
– 2. Chemical: energy stored in bonds between atoms
– 3. Thermal: energy from heat
– 4. Radiant = Light: 4. Radiant = Light: energy from the sun & light energy from the sun & light
– 5. Nuclear: energy stored in the nucleus of an atom
– 6. Sound: energy of vibrating sound waves
– 7. Magnetic: energy of magnetism
– 8. *Mechanical: Energy due to position and motion • Kinetic + Potential= Mechanical
9. Elastic potential Energy: Energy that is
stored in something that
stretches or compresses,
such a rubber band or
spring.
Kinetic Energy• KE is energy of motion. • KE = 1×m×v2
• 2
– m = mass (kg)– v = velocity (m/s)
• SI Unit for Energy is Joule (J)–Joule = kgxm2/s2 (This is NOT an equation—just
another way to write the unit)
Calculating Kinetic Energy
• What is the kinetic energy of a 44 kg cheetah running at 31 m/s?
• KE = 1 m v2
• 2
• KE =
https://www.youtube.com/watch?v=AO117teuR2Q
• Bill Nye Energy:
• On the back of your paper:
• Name as many examples of energy as you can from the video.
• Name examples of energy changes in the video.
Potential Energy (PE)• PE is energy that is stored in an object. 4 types of PE:
1. Elastic PE– Energy due to a stretch (rubber band) or compression
(spring)2. Chemical PE – Energy in the bonds between atoms (foods & fuels)
3. Gravitational PE– Energy due to an elevated position– GPE = m×g×h
• m = mass (kg)• g = gravity=9.8 m/s2 (on Earth)• h = height (m)
4. Nuclear energy: Energy stored in the nucleus of an atom.
Calculating Potential Energy
• A 65 kg rock climber ascends a cliff. What is the climber’s GPE 35 m above the base of the cliff?
• GPE=
https://www.youtube.com/watch?v=AO117teuR2Q
• Bill nye energy 22 min
• Bozeman science KE PE
• https://www.youtube.com/watch?v=BSWl_Zj-CZs
Law of Conservation of EnergyL.o.C.o. Energy--• Energy can not be created or destroyed, it
just changes form.
• Rollercoaster
• mass and spring
Mechanical Energy• Energy can be converted from Potential to
Kinetic, but the total energy doesn’t change
• Total Mechanical Energy = Kinetic + Potential
• ME = KE + PE
Nuclear Energy
• There are two types of nuclear energy• Fission and Fusion • Both forms energy are stored as mass in the
atoms of certain elements. This mass can be changed into energy under the proper conditions according to Albert Einstein's famous equation:
• nuclear fission • nuclear fusion• http://www.pbslearningmedia.org/search/?
q=fission&selected_facets=• Scroll down to fusion
Fusion & Fission • Fusion atoms are "fused"
together• In fusion lighter elements
form heavier elements• Uses
– The middle of stars• Fission the 2nd form of nuclear
energy
• The exact opposite of fusion.
• In fission atoms are broken apart.
• In fission heavier elements form lighter elements.
• Uses
– Hydrogen Bomb
– Nuclear Energy Plants
Rube GoldbergUnbelievable Rube Goldberg Machine - Google Video
•