Who is ?

1
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)

2
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.

3
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

4

• 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.

5

• 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.

6

• 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
  persons 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 persons
  weight has an effect on the stability of the
  boat.

7

• 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."

8
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!

9
Thanks for the information to www.BoatSafeKids.co
m 5102 SE Nassau Terrace, Stuart, FL
34997Sponsored by International Marine
Educators, Inc.
10
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

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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. Its directly
  related to the volume (size) of the object.
• Greater Volume - Greater Buoyant Force

12
Payloads - Weights
and Values

• 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