2013 Physics Olympics

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DIY Physics

Overview

Western Kentucky Physics Olympics is a half-day competition consisting of a pentathlon of challenging problem-solving activities that reward teamwork, creativity, and communication. The WKU Department of Physics & Astronomy invites each high school to send one or more teams of four to compete in the 2013 Western Kentucky Physics Olympics. This year’s event will be held Saturday, February 23 from 8:30 a.m. until about 2:00 p.m. in the Thompson Center, Central Wing on WKU’s Bowling Green campus.

The 2013 Physics Olympics competition will commence with two activities that involve competitors arriving at the event ready to compete with things the teams have designed, constructed, and tested. The competition entitled Bouncing Polymers requires each team to use household ingredients to create a bouncing ball that bounces to the greatest height when dropped from a fixed height. For Carbonated Geysers each team will construct a system such that a Mentos powered geyser of diet soda pop spews to the greatest height and can be aimed to fill a distant bucket as efficiently as possible. This year’s “Calculation/ Communication Challenge” is entitled Molecular Isomers and will require each team to divide into pairs and cooperatively transform one deadly molecule into an innocuous isomer form. The "On-the-Spot Activity” and "Order-of-Magnitude Quiz" will remain cloaked in secrecy until the day of the event.

 

Do-Ahead Event: Bouncing Polymers

The object of this Do-Ahead Project is to make a bouncing ball from household ingredients. Once you understand the basic technique, you can alter the recipe for the ball to see how the chemical composition affects the bounciness of the ball. Here's a list of materials you need to gather to make bouncing polymer balls: timer 2 containers for mixing measuring spoons spoon or craft stick to stir the mixture warm water borax (used for laundry) cornstarch (used for baking) school glue (e.g., Elmer's)

Pour 2 tablespoons warm water and 1/2 teaspoon borax powder into the first cup. Stir the mixture to dissolve the borax.

Pour 1 tablespoon of glue into the cup labeled 'Ball Mixture'.

Add 1/2 teaspoon of the borax solution you just made and 1 tablespoon of cornstarch. Do not stir.

Allow the ingredients to interact on their own for 10-15 seconds and then stir them together to fully mix.

Once the mixture becomes impossible to stir, take it out of the cup and start molding the ball with your hands. The ball will start out sticky and messy, but will solidify as you knead it.

Experiment with the ratio between the amounts of glue, cornstarch, and borax. You can also vary the diameter of the finished ball, how long it takes to solidify into a ball. The goal is to create a ball that bounces high when dropped from a height of 2 meters. Don't eat the materials used to make the ball or the ball itself. Wash your work area, utensils, and hands when you have completed this activity.

1. Each team may bring one ball to the competition for judging.
2.  Each team’s bouncing polymer ball will be inspected by the judges to ensure it was made from the listed ingredients.
3. Rankings are determined by the height in centimeters that the ball reaches when rebounding off of a concrete floor after being dropped from a height of 2.00 meters.  
4. All contestants will ensure that their entry works through the application of physics principles and generally follows the spirit of the competition.

 

Plan-Ahead Event: Carbonated Geysers

The year’s Plan-Ahead competition requires teams to construct and demonstrate carbonated beverage soda fountains in two contests.

When a Mentos candy is dropped into a bottle of soda, an impressive geyser-like eruption is created. This is a physical reaction, not a chemical reaction. The vigor of the geyser depends on various factors that affect the growth rate of carbon dioxide bubbles. In a carbonated beverage, dissolved carbon dioxide gas forms bonds with the water and surface tension helps keep the bubbles of gas suspended in the liquid. The rough surface of the Mentos candy creates more surface area and more rough edges to promote a much more abrupt release of bubbles. Foam is rapidly created when the pitted surface of the Mentos allows the gelatin and gum arabic in the candy to come into contact with the CO2 gas in the carbonated beverage. Foaming is maximized in diet soda by the artificial sweetener affecting the surface tension. Details of the reaction have been published in a June 2008 article in the American Journal of Physics, "Diet Coke and Mentos: What is really behind this physical reaction?" (Coffey, T., American Journal of Physics 76(6): 551–557).

1. Soda fountains may be created using any commercially available soda sold in a 2 L or smaller plastic bottle. Teams must provide their own unopened soda for the competition. Every bottle of soda must be presented to the judges to ensure that it is factory sealed and unaltered at the beginning of each contest.
2. Only physical nucleation may be used to induce the fountain.Chemical reactions, physical shaking, heating, and sonication are not allowed. The soda bottles may not be externally pressurized prior to or during the competition.
3. Teams must provide their own nucleation material. There is no limit to the form or amount of nucleation material a team can add to the 2-liter bottle of soda.
4. Bottles and caps may be modified in anyway to effect introduction of the nucleation material and subsequent soda fountain direction or shape.

5. In the bucket filling contest, the container used to catch the geyser's output will have at least a 0.25m opening, be tipped toward the launch area at an angle of 30 degrees from the vertical, and will have it's front edget 4.0 meters away from the end of your nozzle. Bottles may be placed on stands or in holders as part of the competition.

6. Each team will be allowed three trials, to be divided as they choose between the bucket filling contest and the height contest. All three trials may be used for one contest, with a score of zero assigned for the contest with no trials.
7. The bucket filling contest score is computed as the number of milliliters captured in the target, measured to the nearest 5 milliliters.
8. The height contest score is computed as the number of centimeters achieved by the highest visible bit of soda foam, measured to the nearest 5 centimeters from the top of the nozzle.
9. Rankings for the competition will be based on the greatest total achieved by each team.
10. Allteam membersmust wear splash proof safety goggles during the competition and shall ensure that their entry works through the application of physics principles and generally follows the spirit of the competition.

 

Event 3: Molecular Isomers – Communication/Calculation Challenge

Your team will be given basic information about molecular isomers then asked to divide into two groups. Two members of the team will devise a step-by-step strategy to transform a given molecule into a particular isomer. The remaining two team members will be presented with the created set of instructions and with no additional communication will be required to use the provided parts to construct the specified isomer.

 

Event 4:  Inertial Challenge – Impromptu Team Activity

Activity is the key word for this competition, with the goal being for each team to achieve the desired result as quickly as possible. The situation is designed to reward teamwork and common sense thinking as well as knowledge of physics. Every team will come away with smiles and good memories regardless of how well they master the particular challenge.

 

Event 5:  Order-of-Magnitude Quiz (also known as Fermi Questions)

Arrive at a reasonable approximation for the value of a complex situation with very little to no information available to directly compute the answer. In this quiz, the contestants will need to quickly make assumptions for values to use in simple calculations in order to arrive at the "correct" answer, stated as the power of ten of the number that fits the accepted value.

Teams will receive 7 questions to complete within 15 minutes. The teams can divide the work in any way they see fit, but only one answer per question per team will be accepted. Answers will be judged according to how many orders of magnitude the team's answer is from the judge's solution. The lowest score wins -- 0 points awarded for the answer accepted by the panel of judges, with 1 point scored per order of magnitude from the accepted value.

Examples of Order-of-Magnitude Quiz questions include:

How many electrons enter the starter motor when a new, full-sized pickup starts?

How many times would a tire of a Ford Taurus rotate when driven from NYC to LA?

Estimate the number of gallons of gasoline used annually by all the cars in the USA.