“Rock Your Boat” Challenge
Introduction
Boats come in all sizes, shapes, and colors!
And, some have trouble going the same direction as others!
Have you ever wondered how a large supertanker filled with oil can float?
Objects submerged in a fluid such as water appear to weigh less than they do when they are not in the water. The liquid exerts a buoyant force on the object.
Archimedes is credited with discovering that the buoyant force on an object is equal to the weight of the displaced fluid. He is said to have discovered this principle in his bath while trying to think of a way to determine whether the king's new crown was gold or a fake. Legend says that he ran naked through the streets shouting, "Eureka."
Archimedes Principle also applies to floating objects. An object floats on a liquid if its density is less than that of the fluid. For our supertanker to float it must displace a volume of water equal to its weight.
Objective:
· To build a boat out of cardboard and tape capable of holding two people that can be launched and paddled across a pool.
· To apply Archimedes' Principle to your design.
Materials:
1. Only cardboard and tape may be used to construct the boat.
2. Only corrugated cardboard will be allowed. You may NOT use any other objects to contribute to the structural rigidity or the craft's flotation ability.
3. You can use any type of tape – clear or duct tape. NO GLUE!
Design Parameters:
1. The boat should accommodate 2 student members (skippers) who are good swimmers.
2. You may paint your boat with water-soluble paint as part of your decorations for your theme. Be creative!
3. Rafts are not allowed.
4. The maximum length is 7 feet. Your boat must be wide enough to fit through the doorway.
5. Swimming on a cardboard surfboard is not allowed. No appendages are allowed in the water.
6. Both student skippers must be visible while the boat is in the water.
7. Boats must be free of sharp edges, objects with pointed edges, or any other menace.
8. All boats may be propelled through the water by:
o A) utilizing paddles
o B) constructing a device that will power the vessel, such as a paddle wheel.
o C) using a sail
o D) any combination of a, b, or c.
9. No arms or legs may be in the water to assist with stability or propulsion.
10. To qualify as a finisher, both teammates must be in the boat at the end of the race.
11. Extra credit will be awarded for a theme.
o A theme can consist of coordinating clothes, hats, etc.
o A theme can consist of decorations on your boat. All decorations must be made of cardboard and be affixed to the boat with approved tape. You may also decorate your boat with markers Ino paint, etc.) in addition to affixing cardboard decorations.
o The content of the theme must be appropriate, following the rules described in the student handbook.
You will work in 4 member student teams.
Grading Guidelines:
1. There will be a group grade for your boat. Both teammates must be in the boat.
o Any boat that even makes it off the starting line will earn 180 points.
o Any boat that successfully negotiates one-quarter of the pool's length will receive 185 points.
o Any boat that successfully negotiates one-half of the pool's length will receive 190 points.
o Any boat that successfully negotiates three-quarters of the pool's length will receive 195 points.
o Any boat that successfully negotiates the entire length of the pool will receive 200 points.
2. The race will be timed. Winning times and pictures will be posted on the LACHSA website.
3. There will be an individual grade awarded for your summary of the project. It must include the following:
· A one paragraph description of how you would change your design. In other words, what part of your design was effective? What part of your design did not work? How would you change it? 25 pts
· Describe three things that you saw other students do that you consider being very effective. 25 pts
· Archimedes Principle states that "The buoyant force on a body immersed in a fluid is equal to the weight of the fluid displaced by that object." An object floats when its weight is equal to the buoyant force. Write a one-paragraph description of how this principle applies to the floatation of your boat. 25 pts
· Describe how you would calculate the buoyant force exerted on your boat by the water. What measurements would you take and how would you interpret them? 25 pts