1. Matter & Energy Give me matter and motion, and I will construct the
universe.
 Rene Descartes

2. ENERGY

3. It is important to realize that in physics today,
we have no knowledge of what energy is.
 Richard P. Feynman

4. When is expenditure of energy required?
* tossing a ball
* lifting a rock
* launching a rocket
When is expenditure of energy not required?
* Rocket coasting through space

5. Satellite orbiting
Earth requires no
expenditure of
energy.
Expenditure of energy seems to
require motion and force.

6. Some Varieties of Energy
* Kinetic Energy (Energy of Motion)
> Thermal (heat) energy
* Potential Energy (Stored Energy)
> Elastic energy
> Gravitational energy
> Chemical energy
> Electrical energy
> Magnetic energy
> Mass-energy
* Radiative Energy

7. Kinetic Energy (KE)
Mass (m)
Speed (v)
* KE  m
* KE  v2

8. Heat & Temperature
Higher Temp Lower Temp.

9. Conservation of Energy
Energy neither appears nor disappears. It may be
converted from one kind to another, in which
case the total amount of energy is unchanged.

10. Conservation of Energy + Mass
* Einstein: mass and energy are interchangeable
mass
(speed of light)2
* Total of mass + energy is what’s really conserved!

11. equivalent to detonating
0.1 kg mass  Energy
equivalent to detonating
1 million tons TNT
(1 ‘megaton’)

12. MATTER

13. ATOMS When it comes to atoms, language can be used
only as in poetry. The poet, too, is not nearly
so concerned with describing facts as with
creating images.
- J. Bronowski

14. Old Picture:
Electrons
orbit
Nucleus:
larger orbit
more
energy
(‘Bohr Atom’)

15. New Picture
Electron ‘cloud’

16. Probability of Finding Electron
Distance from Nucleus

17. In 3-D
lowest energy
next lowest energy or or
next lowest
energy

18. Hydrogen
Energy
Levels
(1 electron)
Excited States
Ground State

19. Sodium
Energy
Levels
(11 electrons)

20.  Atoms are usually neutral:
# protons = # electrons
 Ions: atoms with one or more electrons added and/or removed
 A chemical element consists of atoms with equal numbers of protons

21.  Isotopes consist of atoms of an element with a different number of neutrons
#protons #neutrons
e.g.,Hydrogen 1 0
Deuterium
Tritium
 Atoms can bind together in molecules
 A molecule is the smallest unit of a compound
e.g., CO2, H2O, etc

22. Phases of Bulk Matter
Solid
Liquid
Gas
Plasma

23. Fully Ionized
Plasma
(Avg. Kinetic Energy)
Temperature
Gas
Liquid
Solid