• Becquerel discovers "radioactive" materials: namely uranium salts
• Gives Pierre and Marie Curie the job of isolating radioactive materials
• They share the Nobel prize for discovery of radioactivity and radium.
• Rutherford finds alpha and beta rays looking at "Becquerel rays"
• Villard finds gamma rays
  

• Alpha particles are helium nuclei -- 2 protons and 2 neutrons
  
• Beta decay depends on an electron either
  
• being produced when a neutron turns into a proton and then an electron must be spit out of the nucleus
• being absorbed, or captured, by a proton so that it turns into a neutron
• Gamma decay is a photon with very high energy
• 100s of KeV or Mev in energy
• compared to xrays in the 10s to 100 KeV
• compared to visible light in the 0.5 - 2 eV
• ²³³Pa ₉₁ has 91 protons, 142 neutrons, 91 electrons, and 233 nucleons.
  

• Number of nucleons is conserved
• Element may transform up or down the periodic table to a different element depending on the number of protons remaining after the decay
• Element may stay the same and just release energy from the nucleus (gamma decay)
• Charge is conserved

• The half-life of a radioactive material (one with unstable nuclei in it) is defined as the time it takes for half of the radioactive nuclei to decay to their decay products (called daughter or child products).
• For instance, if the half-life of helium-8 is 0.119 seconds, then if 50 grams of helium-8 decayed for 0.119 seconds, there would only be 25 grams of helium-8 left and the rest would be made up of the daughter material.
  

• Nuclear fission is the splitting of a large nucleus into two smaller nuclei with the release of neutrons and energy
• For a nuclear power plant, U-235 is struck by a neutron becoming U-236.  U-236 is unstable and undergoes fission.  It can break into a number of different daughter particles like:  1) Kr and Ba, 2) Xe and Sr, or 3) Pd and Pd for example.
• The neutrons which are released go on to create more unstable U-236 atoms for more fission to occur.
• The energy is used to heat water so it either turns to steam or is just really hot water under pressure.  This heated water then turns a turbine (remember these) and makes a coiil rotate in a magnetic field to GENERATE power !!
  

• Latest and Expected Applications for Nuclear Power Plants in the U.S. (2007-2009)
  
• First New Generation EPR Nuclear Plant Built in Finland -- to be finished in 2009-2011
  
• EDF (France -- EPR Nuclear Power Plant) Nuclear Power -- this website tells about the latest designs in power plants
  
• BBC News Website:  Guide to Nuclear Power -- use this website to explore the basics of nuclear power

• Scientific American Article, Sept. 2006 Issue:  "A Plan to Keep Carbon in Check."
• Scientific American Article, Sept. 2006 Issue: "The Rise of Renewable Energy."
• EDF (France -- EPR Nuclear Power Plant) Nuclear Power -- this website tells about the latest designs in power plants
• Alternate Energy in the News

Narrated by Erick Avari

Questions to Consider:

1.  What different alternate energies did the DVD explore

2.  Pick one and explain it

3.  What energy source was the most surprising to you?

4.  Which energy source is closest to being used heavily in the US

5.  Which energy source is furthest from commercial use?

6.  Which would probably be one of the best if it can be scaled up?

• Scientific American Article, Sept. 2006 Issue:  "A Plan to Keep Carbon in Check."
• Scientific American Article, Sept. 2006 Issue: "The Rise of Renewable Energy."
• EDF (France -- EPR Nuclear Power Plant) Nuclear Power -- this website tells about the latest designs in power plants
• Alternate Energy in the News
• Scientific American Article, Sept. 2006 Issue: "The Nuclear Option."

• Energy Flow Diagram for the U.S. from Energy Information Administration

• IPCC 2007 Report

• National Geographic Articles, March 2006 Issue:  "The high cost of cheap coal."

• http://science.howstuffworks.com/global-warming.htm

An Inconvenient Truth: A Global Warning !

With Al Gore and www.ClimateCrisis.net

1.  List 5 important points that were presented on the DVD, and explain them in one sentence

2.  What was the most surprising thing you learned from this presentation?

Second time, same as before:

1.  List 5 important points that were presented on the DVD, and explain them in one sentence

2.  What was the most surprising thing you learned from this presentation?

Thermal Energy Examples à Greenhouse Effect à Global Warming

Any calculations should include equations and show all work with units

1.  If you were building a road of steel reinforced concrete, what worries would you have about the effects of temperature variation with seasons?   If a(concrete) = 18 x 10^-6/C and a (steel) = 12 x  10^-6 /C, how different would the expansion be for a steel rod 16 m long versus a 16 m long length of concrete from winter at 10C to summer at 40C?

2.  In the winter, an Al metal signpost which is 30 m high will change its length by how much when the temperature drops 45C.  a (aluminum) = 24 x  10^-6/C

 3. If you shake sugar, it will get warmer.  How much work would you have to do to increase a 2Kg bag’s temperature by 3C if c(sugar) = 0.35 KJ/KgC?

4.  If you were to weight lift strenuously for 30 minutes, raising a 30 kg bar over a distance of 0.5m each minute, how much would your 75 kg body’s temperature increase? c(body) = 0.85 kJ/kgC

5.  Draw the earth and the atmosphere above it.  Then draw the sun.  Add the sun’s rays in such a way as to illustrate the Greenhouse Effect and describe in a few phrases.

6.  List what gases you think are partially responsible for the Greenhouse Effect and Global Warming with sources for them if possible.

Phy101:  Thermal Energy Experiments

Mechanical Energy à Thermal Energy

Test 1:  Use a rubber band from the kit.   Put it on your top lip and feel how warm it is.  Stretch it 20 times.  Put it back on your lip. 

What has changed? 

Test 2:  Use a hammer and nail and a board (provided up front).  Hammer a nail part way into the board and then pull it out.

Describe how the nail feel before/after and why.

Thermal Energy

Test 3:  Name 3 energy transfer mechanisms

b

c

Ask for help if you cannot remember them.

Test 4:  Describe why a floor tile in the bathroom feels cold and why the fluffy rug feels warm – which heat transfer mechanism is responsible.

Test 5:  Check out the 3 objects in your bag:  cotton ball, wood, and metal cylinder.  What do you conclude about each and why?  

Test 6:  If you put your hand near your face (without touching it), what do you feel?  Why?  Which heat transfer mechanism is responsible?

Test 7:  In the TWO diagrams below, a)  depict what happens to the air during a hot day at the shore on the top one, b) depict what happens to the air during the night.  Mark temperature changes in words at various parts of the diagram and air flow with arrows.  Hint:  The earth is able to change temperature more easily than the water.

Main Ideas:

The unit of energy is the Joule, J, in the metric system.  A     J = (k² m²) / s².  Interestingly, this is also the unit of Work.

                                    KE = 1/2 m v²

Is energy due to motion of an object.  Any object in motion will exhibit KE.  It is a
scalar quantity NOT a vector quantity.

  Potential Energy

                                 PE = m g h

Conservation of Energy states that energy can neither be created nor destroyed, it simply changes states (or types of energy).

Examples of Conservation of Energy:

 (1)  A 1 kg pendulum swings from a starting position of 50 cm above equilibrium. What is its speed at the bottom of its
swing?

(2)  The same pendulum swings to 15 cm above equilibrium.  What is its speed there?

Mini Experiment

Bouncing Balls & Roller Coaster Experiments

1.      Bouncing Ball:  Ball, meter stick

a.       Choose a height to start from.  hi =

b.      Drop ball.

c.       Record height ball returns to.  hf =

d.      Calculate the following quantities:  PE before, PE after, Speed ball hits ground with.

e.       Is mechanical energy conserved during fall?  After return bounce?  What happens to the energy of the ball?

f.        Choose another height to start from.  Then calculate how fast the ball is moving part of the way through the fall (for instance, drop ball from 75 cm and see how fast it is moving at 30 cm)

2.      Roller Coaster Problem:  Loop-de-loop, car or ball, meter stick

PE at top, Speed of car/ball at bottom, Speed of car/ball at top of loop

Key Concepts:

F = ma           Newton's 2nd Law of Motion       

Focus in on Newton's Laws:

1.  First and Second Law:  The NET force is the important quantity.  If there is a NET
force, there is an acceleration.  If there is NO NET force, there is no acceleration; BUT there can still be motion (constant speed in  straight line).

2.  Examples of Places where net force must be considered:

Falling objects and air resistance.
Pushing objects across a surface and friction force.

Examples of Newton's Laws -- Net force and terminal velocity

Units of Force (N), Weight (N), Mass (kg)

Ch. 3:   Projectile Motion

        Vertical motion controlled by gravitational forces and any air resistance that occurs.
        An object undergoing horizontal motion feels no unbalanced forces (once thrown/shot
        object is released).
        Equations of motion can be chosen for each type of motion.

                Vertical:    d_y = 1/2 a t²       V_fy = V_iy ± at

                Horizontal:  d_x = V_ix t
 

When a ball is thrown up in the air, it experiences vertical motion.

When a ball is rolled across a table, it experiences horizontal motion.

When a ball is thrown across the room, it experiences BOTH vertical and
horizontal motion.
 

              Galileo showed that we can look at each of the above motions separately.

Phy 101 Motion Problems
Extra Credit Motion Problem from In-Class - Solutions

1.  Your kid Brother drops a coin into a wishing well.  After 2.078 seconds, you and he hear the “plopping” sound as the coin hits the water.  How deep is the well?

Ch. 2 & 3:  Intro to Physics & Society

What does each type of graph look like for the following
situations:

        Constant Motion -- the distance increases with time (straight line with some slope, the steepness of the line is related to the speed), the speed stays the same regardless of time (straight horizontal line), the acceleration is zero

        Acceleration -- The distance increases or decreases with time but the slope changes (as you speed up the slope increases, as you slow down the slope of the curve decreases) thus you see a curved line on distance graph, the speed incresases of decreases with time in a linear fashion (straight line with some slope corresponding to acceleration), the acceleration is a constant at all times (straight horizontal line (non-zero, may be positive or negative))

        No Motion -- the distance remains the same regardles of time (straight horizontal liine), all other graphs are at zero (no speed and acceleration)

        Changing Acceleration -- all graphs are more complicated, distance changes with time in a curved fashion and so does speed, accelearation is changing with time (straight line at some angle)
 

Mini-experiment In Class

Equipment:  Meter sticks & stop watches

Using the above tools and the people in your group.  Measure the
following quantities.

a)  Average speed of a person walking at constant pace.

b)  Average acceleration of person starting from stop to a run.

c)  Your response time when dropping a ruler between fingers
 

Experimental Procedure:   Describe below how you would do the
above 3 measurements.

How many trials would you do? Why?

Data:   Record data below and show calculations of speed,
acceleration, and response time.

Analysis:  Are the values you calculated reasonable?  why or why
not?

What are possible sources of error?

Science -- an intro -- see websites listed below

• Define physics
  
• What is technology?
• What is the difference between the two?
• How does society (YOU) interact with science/physics and technology?
• WHat power/influence does society have on science and technology?
  

• What is critical thinking?
• How do YOU form an opinion?
• What is an informed opinion?
• How does one effectively argue a point?

• What are the facts of the case?
• What are the issues brought out in the study?
• Who is affected by the problem (may or may not be persons directly mentioned in stories)?
• What are possible directions one could take from where the story left off?
• What would be the possible consequences of such actions?
• Ethical, social, economic, and political implications
•  Practical constraints

Please meet in your groups and answer the following questions.  

1. Describe the Greenhouse effect
2.  What are the most important issues surrounding it?
3.  What questions do you have about the Greenhouse effect?
4. Describe Alternate energy
5.  What issues are there about it?
6.  What questions about  alternate energy do you have?
7.  Describe Nanotechnology
8.  What important issues surround nanotechnology?
9.  What questions do you have about it?