Radioactivity Basics

Radioactivity Primer

FINDING OUT ABOUT THE NUCLEUS

Thomsen's Experiment

Rutherford's Model

Chadwick and Millikan

 

Watch the full episode. See more NOVA.

 

RADIATION AND PROBABILITY

The Basics

The Dosages and Such

What is a Detector?

Today, we talked about rules and detectors.   Sometimes detectors are inadequate for us to find all the rules.  What we do in physics mirrors that.  We need to collect enough data, using appropriate detectors, to help us fill out the rules.

Marshmallow Catapults

Trebuchet Project

Benchmark on Projectile and Rotary Motion

Build a trebuchet that is capable of launching a large marshmallow from a distance of 3 to 5 meters, and hitting a target that is .30 m high +/- .10 m. You will have 5 trials to hit your target, and will be graded according to your building design, accuracy, and analysis.

The Trebuchet Page

Trebuchet Physics:  A Student View

Trebuchet Simulators

hTrebuchet Experiments (needs Java)

Nova Builds a Trebuchet

Questions for Analysis

(To be completed individually)

1. Where is the biggest frictional issue in your machine?  Explain why this matters to the momentum of the mallow.
2. Determine the maximum range for your trebuchet, t(calc), and the initial values of v(x) and v(y) including a diagram  using logger pro
3. How could you determine F(net) of the mallow?
4. How will the momentum of the projectile change if we use jawbreakers instead of marshmallows?  An orange?  Why?
5. Pick a time frame for your catapult.   Determine the change in t, the acceleration due to gravity, and the distance traveled.  Based on this, calculate v(i) at the beginning of the interval and v(f) at the end of the interval in the x and the y directions.   Choose your interval carefully so you are not mixing y(up) and y(down)
6. Write a three to five paragraph summary of how you would change the design if you built another machine, and what you have learned about physics.  Include the following terms:  potential energy, kinetic energy, frictional force, net force, acceleration of gravity, vector errors, kinematic equations, independent x and y motions.

STATICS

Reflection on Bridge Building

1. How much did your bridge hold?
2. How much did it cost, and how did you minimize your costs?
3. What is the mass of your bridge?
4. Calculate the force weight of the bridge, and the force weight of the load applied.
5. Calulate a ratio to show me the strength of the bridge (load/bridge)
6. Using the member data sheet, which bridge member held the greatest load? How do you know?
7. Can a member experience both compression and tension? Explain.
8. IS your bridge model a good fit for the bridge you made in the program? Why or why not?
9. Draw a force diagram for your bridge when the truck is on the left-hand side of the structure.
10. How does friction matter in this project?
11. What have you learned in this project about statics, force diagrams, angles, and vectors.

This entire sheet should be 1-2 pages long, hand-written or typed, and due on Monday, November 8.

Dream Vacation Vector BM

A Dream Vacation: Courtesy of Vectors and Google Earth

You are headed on a dream vacation! Start at Manchester, and zoom around the globe using Google Earth in the North Lab. At least one place must be south of the equator. As you travel (on at least five stops), keep track of the latitude and longitude for each place, and create a scrapbook of activities and interesting highlights (You can print photos, and please write down 2 or 3 observations for each place. Ask other classmates who scrapbook for ideas...

Note the length and the angle of each leg of your trip. You must resolve this into component vectors.

NOTE: You can take a partner on your trip, but the component vectors and the reflection must be done individually.

REFLECTION QUESTIONS

• When you are finished, determine the net displacement from Manchester to your last location. Include a vector heading. Compare this to the value created by your component vectors. DO THEY MATCH? WHY or WHY NOT?

• Reflection questions that must be answered INDIVIDUALLY on the back of one of the graph sheets.

a) Would Google Earth or the component vector method be better for pilots?
b) Based on the component vectors and the curvature of the earth, could we easily determine a scale where 1cm = _____ miles. Why or why not?
c) How does a GPS use vector determinations as it calculates location? Did this give you any unexpected results? Explain.
d) Give three examples where a vector must be exact to the nearest mm.
e) Give three examples where a vector must be exact to the nearest m.
f) Give three examples where a vector must be exact to the nearest km.
g) Given what you have learned about vectors, when are scale drawings useful? When should you switch from a paper map to a digital device?

h) What did you learn during this project?

Vector Golf 2010

Step 1: You, along with one or other designers , will be putting together a 9-hole golf course. The maximum area available for the golf course is a land area that is 1760 yds by 2650 yds (you do not need to use all the land). A lovely creek (not a river) runs through the land, and there are trees on two edges, and a housing development on a third. You will need to have PAR information to do this, but these values are approximate, so you do have some leeway.

For the purpose of this activity, cost is no object, so trees and sand traps can be added at will.

Establish a scale: __________ yards = 1 cm

Draw a detailed sketch of your course using the paper by the meter sticks and hand in. Make sure you have added a compass rose and have marked the scale on your paper. Color the course using colored pencils or crayons.

Provide a vector length and heading for the first leg of each hole (We will do this on Monday).

Hints: Club houses are often 6000-15000 sq. ft. Houses are often 1800-4000 sq. ft., with the upper range representing a mansion-style home.
If you choose to make a mini-golf course, you have an area that is 100 yds by 500 yds, and must include a clubhouse, a parking lot, 9 holes of golf, and a snack shop On one side of the course must be a go-kart course.

Hint: Google 'golf course design' if you need a sample to get ideas.



Step 2 :
Each person in your group will make a scale drawing of one hole, using a scale of 3 cm = 120 yards, in Power Point. The scale drawing will be done digitally using Power Point, but three copies of the hole must be handed in. Label the drawing with a hole number, mark the tee with a T, and the hole in a flag. Make sure the compass rose on this drawing matches the orientation of the hole on t he master course. The master course must also be handed in.