Modeling and Questions about Radioactivity

1. a) Using things available in the classroom, construct a model of the Rutherford experiment.

2. On a whiteboard,

   a) Explain the difference between a detector and a probe.

   b) Explain the difference in half life between I-123 and Th-229. (Use yesterday's sheet).

   c) Contrast fission and fusion.

   d) How would you respond to an extremely obsessive person who wanted to avoid radiation at all costs.



 
 Ideas from the video:

 *Secrets of the universe
 - 27 km circumference (about 5,000 trips/second)
- Experiments, not just 'Theory'.
- 270 degrees (brrrrrrrrrrr).
 -Billions of dollars.
 - 5,000 pharmacists, plus computer staff, plus maintenance, housing, food workers, constructors.
 - Magnets 'Steer' particles.
 - 10,000 EB data/second.
- International collaboration particles.

Twitter Quiz #1

Today's Twitter Quiz question:

Tweet to 40404 as follows:
@mapowell Name, B1. 1. 2. 3.
(me) (you) (block) (answers)

1. List three benefits of radioactivity.
2. Which type of radiation do you believe is most dangerous and why?

The Story thus far....8/23/2010

Thus far we have covered:

alpha decay
beta decay
gamma decay
fission
fusion
parent isotope
daughter isotope
half-life curve
radiation dangers
benefits to society

Designing a Rollercoaster

http://www.funderstanding.com/coaster

Create a roller coaster that work. Using TE = PE + KE, and the speed at the bottom of each of the three hills, determine the PE at the top of each hill. SHOW WORK BY TAKING A SCREEN SHOT and printing, then determine the math for Hill 1, Hill 2, and the Curve. Does this account for friction?

Check the height of your coaster against records at

http://www.ultimaterollercoaster.com/

http://www.rcdb.com/

What is the average mass of a single roller coaster car with 4 passengers? What would be the Force weight in Newtons? (Remember, 1 kg = 2.2 lbs)
What is the critical factor in going around the curve?
Are today's coasters TRUE coasters (depending on PE only), or coasters with a booster system (chain drive)? Explain.
What type of wheels are best for a roller coaster, in your opinion. Explain, using the concept of moment of inertia.

Find out the dimensions of a roller coaster you have actually ridden using the Roller Coaster database. What observations can you make on its thrill factor, it's material construction, and its length? Based on the information found in the funderstanding coaster, which of them is more of a thrill and WHY?

April 19

You will be completing two labs today. These must be handed in individually. Your effort is graded on a) your logic, b) your sketches for each question and c) your evidence (data).

Lab 1: Directions are found here. The simulation is located at http://phet.colorado.edu/sims/the-ramp/the-ramp_en.jnlp

Lab 2: The simulation is located at http://phet.colorado.edu/sims/lunar-lander/lunar-lander_en.html Your goal is to create a net force math problem that uses data collected from the lunar lab simulator, with an accompanying force diagram.. This data must be collected as the lunar lander is moving DOWN. If I enter in this data, the lunar lab must not crash.

Andy, you need to read the material on induction in the physics book. Then, go to here and here to test out your ideas.

PHYSICS 1 TEST TOMORROW

Bungie Barbie

Set up the equipment as shown . Remember that you need to tell the Logger Pro what type of force probe is attached...it will not do so automatically. You can use a motion detector below Barbie to determine Barbie's a(net) (hint: the slope of the v-t graph)

Figure 1

Procedures:

Produce as many different graphs as possible by dropping Barbie with at least 3 different cords(rubber bands, yard, fishing line, tape, or other materials are in the cupboard underneath and between the two sinks) and materials. Describe your procedures in 3-6 sentences.(Rubber bands are in a box under the left side of my desk.

Data / Observation:

Sketch, describe, print or save your graphs for each "jump". Clearly indicate which cord or material was used. Also include information such as the amount of force and the time over which the force was applied. Record any relevant observations you saw during the jump. Autoscaling the jump will help

Calculations:

These will be done tomorrow in class.

Conclusions:

State which cord you believe to be best for bungie jumping. Support your choice with your data.

Questions:

Record any questions that arose in the lab. Include any answers to the questions you may have found.





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Physics 3: Andy, you will be working with 2 sims

http://phet.colorado.edu/simulations/sims.php?sim=Resistance_in_a_Wire

and

http://phet.colorado.edu/simulations/sims.php?sim=Circuit_Construction_Kit_DC_Only

Your house has new thick wiring that has very little resistance. Right click on the bulb and select change value to adjust the resistance of the bulb.

i) (0.5 pts) With the resistance of the bulb at 37 ohms, how much power is going into the bulb? ii) (1 pt) How does this bulb brightness compare to the brightness of the bulb when the resistance of the bulb is 1 ohm? Explain the physics reasoning behind why the bulb brightness changes. iii) (0.5 pts) If you had a 100 Watt bulb plugged into one outlet and a 1500 Watt electric heater plugged into another outlet, how would the resistance change?

b) New heavy duty wires will have only a small resistance. If your house is an older home (i.e. built 100 years ago), the old thin wires will have larger resistance. This increase in resistance in the wiring has several effects. In the simulation, select the developer panel under the options menu and begin increasing the resistance of the wires. You can measure the voltage drop between any two points in the circuit by using the volt meter.

i) (2 pts) Set the bulb resistance to be about 2 ohms. As you increase the resistance in the wires, what changes do you see in (1) the current, (2) where the electrons loose their energy, and (3) the amount of power (energy per second) that is being used by this circuit? (Hint: use all of the visual cues and the tools you have like the volt meter to explore the changes). Be sure to explain the physics reasoning behind why these changes make sense given an increase in the resistance of the wires. ii) (1 pt) Given your observations in the previous question, how would using old thin wires affect the brightness of the bulb and the temperature of the wires compared to using new, thick wires with very little resistance? Explain.


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Kelly, go to http://phet.colorado.edu/simulations/sims.php?sim=Geometric_Optics and do the activity found here

West Point Bridge Designer

PART 1:  Start by working with ONE partner to work on free body diagrams, found here

The quiz that we will have later this week will assume you have done this materials.  To do it well will take 15-30 minutes.

PART 2:

Go to the lab, and then download the West Point Bridge Designer software.  Your goal today is to make a truss bridge at a height of at least 12 meters that has the lowest cost possible.  You may work with ONE PARTNER ONLY.  When you get done, optimize your bridge, than forward the bridge design file as an attachment to me at marciarpowell@gmail.com The bridge with the lowest cost will receive the most points. 

PART 3:  You will want to print a copy of the bridge design, as you will be making a model, so when you get done, your next step is to use a sheet of paper and make a usable scale drawing, where 1cm= 1m  (Use the member list on the program to see the lengths that you will need). 

PART 4:  If you get done early, please look at the first 10 pages of the link on 5 Steps to Building a Bridge, which explains truss vocabulary.  Turn in the scale drawing at the end of the hour.

 On Wednesday, we will build the bridge.  You can use manila file folders or balsa wood (popsicle sticks) as your material of choice.  The glue used will be Elmer's white glue or Elmer's wood glue.  DO NOT bring Gorilla glue for this project.  The emphasis is on the building process, and accuracy, not on how strong Gorilla glue is.  You may wish to bring some clothes pins to use as clamps.

The links below are very helpful.  Tweet me if you have questions.

Hints on Building Bridges

5 Steps to Building a Bridge

Optimizing your West Point Bridge