Next MeetingNewsletterPast NewslettersAmusement Park Related

Thanks to the folks at James Madison University for hosting the joint meeting of the CSAAPT and the VIP meeting. JMU did a lot to help bolster the quality of the meeting. Thanks also go to Andy Jackson, VIP Vice President, for arranging the joint meeting at JMU.

Next Meeting
The next VIP meeting will be held at the VAST conference in Roanoke. We are sponsoring 3 sessions. A disscussion session, Amusement Park physics (in cooperation with the sceince Museum of Virginia), and a demo session. Nov 8 & 9. Hotel Roanoke

Toy Science
by Tony Wayne
Topic: Rotational Inertia
There is a toy gun on the market now that shoots little foam disks. The gun has few market versions differing in general gun shape, color and price, $5-10. The most common one I've seen it the "Power Rangers..." or "Batmen Disc Shooter." The disks the gun shoots are about the size of 2 stacked silver dollars. When the disks are shot out of the gun they spin, like a frisbee. This spinning is what gives them stability. The stability comes from rotational inertia. Spinning the disks increases their inertia. With an increase in inertia, the disk better resists any change in motion. In other words, spinning disks fly farther because they don't wobble in the air and don't succumb to air resistance as quickly as a non spinning disk.


Take a disk and with a permanent magic marker, color in a quarter of the disk. Shoot the disk horizontally.

Coloring the disk makes it easy to see it spin. Why is it the disks all curve to the same side when I shoot them and then curve to the opposite side when I shoot the gun upside down? Frisbee's experience the same problem. (That's why Dr. Adler invented the Aerobee.) The answer can be broken up into 2 parts, lift, and the principle of gyroscopes.

For any flat disk being thrown through the air, the lift is not uniform over the area of the entire disk. The greatest amount of lift occurs at the leading edge.

The principle of gyroscope says that an applied force on a rotating object a act as if it were applied 90 later in the object's rotation. This means the maximum lift will be acting as it were not at the front but to the side.

This causes the disk to angle during the flight such that the far side rise and the near side droops. The disk curves.

Reverse the direction of spin and the disk consistently curves to the other side.
Note: These same principles can be demonstrated with a frisbee or pie plate. ...I just needed an excuse to buy the gun, <grin>.


This is my proven method of building a successful three section 2 Liter Water Rocket that goes very high. I've redesigned it to be fabricated from readily available materials for your convenience. This is not a "quick and dirty" method because you will have to allow several days for the Goop Adhesive/Sealant to set up hard, before using. When the Goop Adhesive/Sealant has been allowed to hardened, the nose cone will be water tight. This will allow you to experiment with various amounts of water (for weight) in the nose cone to get optimum height.

TOOLS REQUIRED: Knife, scissors, pencil (or stick) with mark 3.25" from end, caulking gun, flat table top, small metal rod about 1/8" diameter, permanent ink marker, ball point pen.
MATERIALS REQUIRED: 2 each empty 2 liter bottles, DOW CORNING Stryofoam R-3 Sheathing, GOOP Clear Household Adhesive/Sealant (in caulking tube), 3/4" or 1" masking tape, 2" wide clear package tape, Dixie Textile "Stuck Up" spray adhesive (or substitute with another high solids spray adhesive that will stick to outside walls of 2 liter bottle, yet will not dissolve polystyrene fin material.

By weighing empty 2 Liter Bottles, I found that Swepps and Canada Dry have heavier bottles than Coke or Pepsi. The discount store brands had the lightest bottles. The heavier bottles weigh more because they have more plastic resin, and probably thicker wall thicknesses.

Since half the bottles used for construction will be part of the pressurized system in the bottom portion of the rocket, I save the best bottles for this section of the rocket. Visual inspection can sort out most rejects. Look for irregularities such as: air bubbles trapped in the walls of the bottles, scratches, cuts, dent creases, etc.

Also, for bottles selected to be the bottom (pressurized) section of the rocket, it is always good to pretest it for launch tube sizing. Simply slide the bottle over the launch tube of the 2 Liter Launcher. If the neck of the bottle is too small and does not easily slide over the launch tube, reject it and use it for a nose cone.

Other bottles that have been scratched, dented, flawed, or culled out (for any reason), will be selected for the top "nose cone" portion of the rocket.

Chose two bottles. One "good condition" bottle for the pressurized bottle section, and another bottle for the top "nose cone" section. The first tasking is removing the labels. Carefully peal off the labels, without cutting the bottles.

Take a bottle selected for the top portion "nose cone" of the rocket. Locate a spot that is on the side of the bottle, near the base, just below the molded circumference ridge, about 2 inches from the bottom. With a knife, puncture a slit large enough to inset scissor blades. With scissors, cut around the circumference, cutting off the bottom "base" section.

Clean soda beverage residue from inside of the bottle and thoroughly dry. Clean and dry the base too. Remove bottle cap.

With the Goop adhesive, squirt two 1/4" beads around the inside circumference of the top portion of cut bottle, about 4 inches from the cut edge. Shove the cut off base section (bottom end first) up inside the bottle. Using a pencil or similar object with a mark 3.25" from one end as a depth gauge, put in neck hole (with bottle cap removed). Continue to slide the base inside the bottle until it indicates that it is 3.25 inches from the outside edge of the small end of the bottle. You will notice that the clear adhesive has been forced between the two bottle sections, making a nice airtight seal. I like to test the airtightness at this time by LIGHTLY blowing into the small end of the bottle.


, you could inhale the fumes from the adhesive. If air passes through, that is bad. You will have to quickly push out the base with a stick, and repeat procedures in this paragraph. Chances are, you will have an airtight seal the first time.

Next, you will join the top and bottom portions of the water rocket. With the Goop adhesive, squirt two 1/4" beads around the inside circumference of the top portion of cut bottle, about 1/4" inches from the cut edge. Before joining, I like to line up the residue from the removed soda labels on both bottles. Now join the bottles by pushing them together. To assure straitness of both bottles, roll the joined bottles, similar to a pastry rolling pin, on the flat table top.

To reinforce this connection, I spray an adhesive called Stuck Up around the circumference of this connection about 3" wide. I spray the adhesive over a newspaper backdrop. Put the bottle on the launch tube, to prevent it from accidentally sticking to the table. After several minutes, after the solvents from the spray have dried, the adhesive is very tacky. I go around the connection with 2' wide clear package tape. I find it easy to spin the bottle, while on the launch tube, to apply the package tape.

The center section needs to be vented. Heat one end of a small metal rod and poke several holes (by melting) in the middle section only. (Substitute metal rod by holding a nail with pliers.) Do not puncture the top or bottom sections! These vent holes in the middle section perform several functions. They allow fresh air for the glue (trapped in the middle section) to cure. They also prevent pressure build up in the middle section which will separate the middle and lower sections if you expose the rocket sections to sunlight and heat.

All the sections of the body of the rocket has now been joined. Now it's time to add "fill" windows, and later the fins. The fill windows are areas you will be able to view the water level as you fill. Normally, there will be the same number of fill windows as there will be fins. The fill windows are placed between each two fins. The masking tape is placed on the sides of the bottom rocket section full length (about 9") from top to bottom of the bottom section only. After fins are attached and any painting and decoration are finished, this masking tape is removed to provide a window.

One thing you need is good rocket fin materials. Hopefully materials that are readily available. Recently, I've been experimenting with DOW CORNING Stryofoam R-3 Sheathing. It's a greenish blue extruded polystyrene insulation. It's a better grade of polystyrene than the common white polystyrene "coffee cup" material. I found it at Home Depot hardware store. It's 1/2" thick, by 48", by 96". It cost about $7.50 for a full sheet. This will make probably 150 fins or enough for about 50 rockets, which is about 5c per fin. This material cuts very easy with a sharp knife, razor, or band saw. Be sure to select adhesives that are compatible with polystyrene.

I've started working with this material by cutting it in 3.5" wide strips. Of course, by cutting the strips in 96" lengths, instead of 48", there will be a higher yield of fins per sheet. Draw a line with the permanent ink marker down one 1/2" edge of a 3.5" strip.

By using a pattern of a fin which minimizes waste, there will only be waste before the first and after the last fins only. A pattern template should be included with the 2 Liter Launcher package. Note the permanent ink marker line on one side of the template. Position the permanent ink marker line of the template on the same side of the permanent ink marker line of the 3.5" strip. With ball point pen, trace outside of template on 3.5" strip at top, repeat as many times as possible on strip (about 15 times).

Using a sharp knife, or band saw, cut fins from the 3.5" strip. To reduce air friction, I like to use a sharp knife and round off the square corners all the way around each fin, and on both sides, EXCEPT the sides with the permanent ink marker line, which is the side which will be attached to the bottle.

One word of caution - do not attempt to attach the fins with hot melt glue. The hot temperature of the glue will shrivel the bottle, and will also wilt the polystyrene. As the bottle pressurizes and deflates, the bottle actually expands and shrinks, and the hot melt glue, which will not expand or shrink, will crack loose from the bottle.

It is time to decide the position of where the fins will be attached. It is best to place the rocket all the way on the launcher tube. Position the first fin (equally between two masking tape strips (for fill windows) and draw around it on the bottle with the permanent ink marker. Make sure that the position of the fins are not too low which would hit the plywood base of the launcher. Repeat drawing positions for other two fins.

This is a good time to protect the plastic flange by the neck of the bottom bottle. Cover the circumference of this flange with a 5 inch long piece of masking tape. Sometimes adhesives and paints can collect on the top side of this flange and cause problems with the first few launch attempts, until this residue is worn off.

Remove bottle from launch tube, place over newspaper backdrop, and spray the three marked areas. Place bottle back on launch tube for drying. Stack the three fins and spray them together. Spray the side with the permanent ink marker lines only. If you have an electric fan nearby, it would help to blow some air on the fins to reduce any solvent damage to the polystyrene. After several minutes, allowing the solvents to dry, repeat spraying bottle and fins a second time. Separate the fins quickly after the second spraying.

After several minutes, attach the first fin by carefully positioning it over the permanent ink marker pattern. Repeat for other two fins.

Reinforce the stability of the fins to the bottle by adding masking tape, or duct tape, to the left and right side of each fin. First, spray the six each inside corner areas (about 1" wide by 6" long) on both the fins and bottle to be taped with adhesive. Several minutes, apply second layer of adhesive. Cut six strips of tape about 6" long. After several minutes, fold the tape in half (on it's width) and join half to the fin, and the other half to the bottle.

The rocket should stand on it's own. If it's lopsided, it's easy to use scissors to shorten the longest fin. For future painting, it's best to not expose the launcher to sprays, because the residues could get into the trigger system or coat the launcher tube. The rocket now stands on it's own and won't fall over while being sprayed. Now is a good time to screw on the bottle caps on both ends, which will prevent residue from entering the bottles.

The functional part of the water rocket is finished.

Now it's time to decorate the rocket and make it pretty. Test paint reaction on waste fin material. Most spray paints will not be compatible with the polystyrene fins, unless they are a spray acrylic (water base) enamels paint.
One that works well is called Plastic Kote.

For the bottle, Bright Coat Aluminum or Chrome look very nice. Also florescent sprays look good also. If the bottle is first sprayed chrome, it seems like the other colors coat better. Have fun creating your own designs.

After paint has dried, remove the masking tape around the flange and for the fill windows. Remember to allow several days for the Goop adhesive to dry.

On the first day of class I often stage a race between a can of Cream of Chicken soup and a can of Chicken Gumbo. The kids like to think about why the Chicken Gumbo always wins. These students have never had any "real" physics teaching up to this point (with all due respect to my colleagues) and I use the race to them understand just what sort of questions we'll be thinking about in the year to come.

Buy some plastic plumbing pipe of appropriate size through which a stack of magnets can easily slide. Or even make a thick paper tube and wrap it with lots of tape so it is fairly rigid. Wind your coil on the tube. A long vertical tube with the coil on the lower end should be best. Fine wire with many turns is best for your coil. When the magnets are dropped through, the LED should flash. If you connect a red and a green LED in parallel to the coil but in opposite polarity, the two will flash at two different times as the magnet poles pass the coil. You might have to experiment with the coil shape. I suspect that a short coil with lots of layrers should work best.

Another thing you could try: tape a stack of magnets crossways to a drill bit, then chuck it in an electric drill and spin it (be careful, tape it securely so it doesn't fly off and hit someone!) Carefully hold your coil near the end of the whirling magnet, and you might get some LED light.

From Lowell Herr
I will assume you mean right after the books are purchased or handed out. Since my students are going to spend quite a bit of time on the analysis of data collected for labs, I will set up a number of stations set up for data collection.

1. An Inertial Balance (of the PSSC variety) with a digital timer used to determine the period. This will give me a square root function.
2 ULI and a light probe where we examine an inverse square function.
3. Pendulum, ULI, and motion detector. This will also generate a square root function.
4. I will most likely add an experiment using two magnetic wafers. This will generate an inverse cube function when the force between (Vernier force probe) the magnets is plotted against separation.
5. Spring, motion detector, and ULI. Again, a familiar function will be generated.

Students will move from station to station collecting data, enter it into a spreadsheet and work on the analysis. This will take more than one day.

From: Raymond Rogoway
I show Road Runner cartoons, two or three. I ask the kids to write down all the "good" physics they see and all the "bad" physics they see. This demonstrates, and I affirm, how much physics they already know. A slight twist is that I introduce the video as a Physics video and then make a big deal about putting in the wrong one. I ask them if they want the right one or want to see cartoons.
They of course vote for cartoons and that's when I give them the good/bad assignment. Makes for a great discussion after. This is done the very first day of class immediately after taking attendance. The orientation and green sheet and the rest of the stupid paperwork can wait a day or two.
I firmly believe that if you can get the kids consent the very first day or two then the rest of the year goes easier.

Some Tid Bits
These tips were shared at a previous VIP meeting inthe form of a hand out. written by Martin W. Goehle, Monacan High School Richmond, Va
These are a few simple teaching ideas that work well:

1. Marble Drop
Have a 5 cm (diameter) circle drawn on a piece of paper. Let students practice dropping a marble from shoulder height into that circle. Then, using carbon paper, drop for real (catch marble after one hit). Draw the smallest circle possible around the marks. The smaller the circle, the greater the precision. The distance between the radii (target circle and drawn circle) gives a measure of accuracy.

2. Student Run
Mark off in parking lot (parking space lines do well) 4 or 5 equal distance intervals. Have students to time at end of each interval and let a volunteer try to run at a constant velocity. Also, mark off 4 or 5 distance intervals that change with the odd Integers. Reposition the student timers and let a volunteer try to run at a constant acceleration.

3. Power
I'm sure you all know the lab involving running up stairs. Using mass, time to run, and (vertical) height of stairs, power can be determined.

4. Tracks and Graphing
I have aluminum tracks (like what a French door would slide in) cut in different lengths. Students time intervals to show constant v, -/+ a You can achieve the same result putting Hot Wheels tracks on long boards.
The second "tracks" lab they follows this list. It's a good way to integrate graphing concepts with motion.

5. Torque
a. Have a student hold out a meter stick. Using a loop of string and a kilogram "hook" mass, slide the mass farther out along the meter stick.
b. Get two 6' boards (2x6). Divide students into teams of five. On stairs slide the top board (with one student on end) as far out as possible. The other four students are on the other end of the bottom board. BE CAREFUL !!
c. If you do a version of Hewitt's chain of dominoes lab (to introduce simple kinematics and graphing) another use for the dominoes is to give students ten and see who can get the top domino out farthest. You may wish to make rules regarding how they can be stacked.

6. Waves
Take some slinkies out into the hall and line paper cups on both sides. When students send a transverse pulse, one row of cups gets knocked over then the other on the reflection. When two students send transverse pulses in opposite directions - constructive and destructive interference can be more readily observed.

7. Helpful Hints:
a. Sound - If you do a speed of sound with water in tubes and tuning forks, I've found it easier to connect two burets to raise and lower water level, rather than a tube in a tube.
b. Electricity - I buy Christmas lights after the season, cut up the line to separate bulbs, solder a clip onto each end and let students connect those in series/parallel. "D" cells will light them up and it's easier to construct different resistor combinations.
c. Go to VIP meetings (like this one) and regional/national meetings (NSTA AAPT) - you'll get more great ideas than you'll ever have time to try !

FIRST YEAR PHYSICS Experiment 6 - Tracks II
In this laboratory exercise, you will continue to explore graphic relationships involving quantities in simple Kinematics. It is important to be able to graph (sketch) motion observed in a lab; and, conversely, to visualize motion from graphs (sketches). In order to do so, you MUST know what the terms mean and how quantities are measured.


1. Set up tracks that will produce the motion exhibited in each of the following sketches. Confirm your results with me before proceeding.

2. Using the following track schematics, sketch v vs t and a vs t relationships:


1. Make "track" sketches (as in Procedure 2) for Procedure 1 above.

2. Make x vs t and a vs t sketches for Procedure 1 above.

3. Don't forget the sketches asked for in Procedure 2 above.

4. What IS/ARE the connection(s) among the following plots ?
(d vs t, v vs t, and a vs t.)

5. How is non-uniforrn motion characterized ?

Physics on the Slopes
Wintergreen Resort, a four-season resort near Charlottesville, is developing a new ski program, designed to combine education and recreation for high school students taking physics. Although in the embryonic stage at this point, generally the program's set up will be similar to existing programs at Paramount's King Dominion and Busch Gardens. It will involve classroom instruction consistent with existing physics curriculum while adding a field trip element featuring practical application of learned formulae and scientific methods. Some of the same measurement materials that are purchased for amusement park science trips can also be used on the ski slopes, e.g the lateral accelerometer can be used as a clinometer.
Wintergreen will even make guest speakers available in classroom settings to describe the physical properties of snow and snowmaking. The resort has worksheets available for instructors to distribute to students. The ski portion of the package will include a lift ticket, rental skis and a lesson at group rate package prices.
For more information on this program, please contact David Zunker, Director of Ski Sales at Wintergreen, at (804) 325-8165. Keep an eye on the Virginia Instructors of Physics web site for more information. The worksheets will be made available on the site in the next month or so.
The following is an one example of what the worksheet's content will look like. This is only a piece of the worksheet.

Physics on the Ski Slopes Worksheet pg 1 of several worksheet pages

Group Member #1
Group Member #2


Do not be concerned with neatness. Readability is all that is needed. Remember to include units on all steps !!! If you write on the back of the sheet, please indicate this. ** means that these questions will be graded, so answer them completely.

All NON-SKIERS should do these experiments on the POTATO PATCH SLOPE.

(always use SI units).
Determination of Angle and Snowpack
1. Choose a ski slope and determine its average angle by using you clinometer. From the top of the slope, sight the head of a person approximately equal to your height at the bottom of the slope.

** Name of slope:
** Angle of the slope sighted by member #1:
** Angle of the slope sighted by member #2:
** Average angle of slope:

** % Deviation:

2. Using the same ski slope. look up the average snow pack depth for your slope. the numbers will be posted next to the door going to the slopes.

** Average Snow Depth (in):

** Average Snow Depth (m):

Determination of Length of Slope
3. Standing near the ski lift, count the total number of chairs moving UP the slope at any instant.
** Describe how you came up with this number.

** Number of chairs on one side of the lift:

4. Determine the distance between chairs using you clinometer and triangulation. (Sight the second chair when first chair is perpendicular to you.)
** Perpendicular distance to ski lift line:
** 2nd Chair Angle sighted by member #1:
** 2nd Chair Angle sighted by member #2:

** Average Angle: ** % Deviation:
** Show calculations (use average angle) for distance between chairs:

** Average distance between chairs:
** Using #3, calculate the length of the slope:
Wintergreen length: ** % Error:

Determination of the Diagonal ... The worksheets continue on. Because of space we only printed the beginning. Other parts are Energy and the Costs of the Chairlift, Energy Uses in Skiing, Ski Friction and Dynamics, Group Activities and Rest Time.

Dimensional Analysis (or Factor Label)
You know... It is where you use the units of the numbers fo find conversion factors and the answers to problems like, "How many drops of water are in a completely filled gallon jug?" On the following page is a worksheet that can be used at the beginning of the year when you are covering dimensional analysis. The sheet makes for interesting, nerdy, practice. INDY RACING
by Tony Wayne

The "Indianapolis 500" is 500 miles long on a race track that is made with 4 turns. The race takes 200 laps to finish. Depending on how a car races is can get between 1.8 and 5 miles per gallon. (1.8 mph when flat out racing and 5 mph when running caution laps.) The cars can generate 700+ hp and have a weight of 1550 pounds. The car's engines utilize a methanol fuel that costs $3.00 per gallon. Each car is given a pumping tank behind the pits that can only 278 gallons of fuel. The fuel tank holds 40 gallons of fuel. An average speed for the entire field of cars can be as high as 185 miles per hour. The lead car can have an average speed of 233 miles per hour. During a caution lap, yellow flag, the car's will travel around at about 70 mph.

1 What is the length of a lap of track?
2 What is the mass of an indy race car in kg?
3 How much does it cost to fill the car's tanks of gas?
4 How many mile pass before a fuel hungry car goes in for a refueling pit stop?
5 How many gallons of fuel are used in a race when flat out racing?
6 How many gallons of fuel are used per lap by a car when it is flat out racing?
7 How much does it cost to pay for the fuel used to run an entire race when flat out racing?
8 If a car refuels every 20 laps, how many gallons of fuel are used between refueling pit stops?
9 How much time does it take to for the leader to travel around the track once when flat out racing, in seconds?
10 How long does it take for the lead car to finish the race, assuming no yellow flagged laps?
11 How much time does it take to for the leader to travel around the track once during a caution lap?
12 In a race, 25 of the 200 laps are run under a yellow flag. A yellow flagged lap is run when there is a problem on the track and the car's need to slow down. How long does it take to for the leader to finish a race of 500 miles?
13 When racing flat out, how many laps can a car travel before running completely out of fuel? How many refueling pit stop does a car need to make during a race? INDY RACING

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