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Who is ?. Lived: 287 - 212 BC in Syracuse, Sicily Education: Studied in Alexandria, Egypt, under the followers of Euclid Inventions: War machines, planetarium, etc. Initiated: Hydrostatics, static mechanics, etc. Major Writings: Floating bodies, etc.
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Who is ? • Lived: 287 - 212 BC in Syracuse, Sicily • Education: Studied in Alexandria, Egypt, under the followers of Euclid • Inventions: War machines, planetarium, etc. • Initiated: Hydrostatics, static mechanics, etc. • Major Writings: Floating bodies, etc. • 1 of 3 greatest mathematicians of all time: • Isaac Newton (English 1643-1727) • Carl Freidrich Gauss (German 1777-1855)
What is Archimedes’ principle? An object that is partly or completely submerged in a fluid will experience a buoyant force equal to the weight of the fluid the object displaces.
Buoyancy - Defined • Buoyant force applied by the fluid on the object is directed up. • The force comes from the difference in pressure exerted on the top and bottom of an object. • For a floating object, the top surface is at atmospheric pressure, while the bottom surface is at a higher pressure because it is in contact with the fluid at a particular depth in the fluid, and pressure increases with depth. • For a completely-submerged object, the top surface is no longer at atmospheric pressure, but the bottom surface is still at a higher pressure because it's deeper in the fluid. • In both cases, the difference in pressure results in a net upward force (the buoyant force) on the object. • Fb = the Buoyant force • W = the weight of the replaced liquid or gas. • Fb = W
Example: How does a heavy boat float? • A boat, or any other object designed to float, is based on the Archimedes' Principle • If you fill your bathtub with water and get in: • The water rises because you "displaced" some of the water with your body and it had to go somewhere. • You (or an object) must displace an amount of water which is equal to its own weight.
Example #2: Block of Wood • Take a block of wood • Size - 1 square foot • Weight - 50 pounds • Lower that wood into the water. The wood will move down into the water until it has displaced 50 pounds of water. • 50 pounds of water (Force) are pushing back up on the block and making it float.
Boats - Have to have Stability • However, if you (or object) want to remain inside the boat - boat must have "stability" as well • Stability means that it is designed not to tip over easily. • Large ship like an ocean liner or tanker, 1 person’s movement doesn't affect the stability of the ship because it was designed to safely carry lots of weight. • But small boat, like a fishing boat - 1 person’s weight has an effect on the stability of the boat.
Stability Continued • A boat is said to "heel" when it leans over to one side. • This is why you never want to sit or step onto the side of a boat. • Your weight (and/or your gear) - make it "heel" too much, tip over. • Small boat, you and your gear should always stay low and to the center of the boat. • When getting into a small boat, always try to step into the center and keep "one hand for yourself and one for the boat."
Last - Boat Safe Tips For Losing Stability in your Boat • If you fell out, you would be fine (with life jacket on) displacing enough water to float • So, you would be okay, just a little wet and cold. • Just turn the boat back over, stay with the boat, blow your whistle or yell for help. • So, the next time someone says "Whatever floats your boat" tell them about Archimedes and stability and why it's a very good idea to always wear your life jacket!
Thanks for the information to: www.BoatSafeKids.com 5102 SE Nassau Terrace, Stuart, FL 34997Sponsored by International Marine Educators, Inc.
Boat Building Activity • Materials - 1 piece Aluminum Foil • Goal - Build a boat that will stay afloat to hold the most $ amount of money • Team - Plan, Design, then Construct your Boat
Engineering Equations and Terms • Surface Area (SA) = Length (L) x Width (W) • Volume (V) = Length (L) x Width (W) x Height (H) or = Surface Area (SA) x Height (H) • Buoyant Force - Upward force exerted by a fluid floating or submerged object. It’s directly related to the volume (size) of the object. • Greater Volume - Greater Buoyant Force
Penny ($0.01) - 2.51 grams Nickel($0.05) - 4.99 grams Dime ($0.10) - 2.24 grams Quarter($0.25)- 5.55 grams Penny $0.40/gram Nickel $1.00/gram Dime $4.46/gram Quarter $4.50/gram Payloads - Weights and Values