Notes: Buoyant force
Finish LW #4Notes #2 Buoyant force DO NOW!TODAYS AGENDA
Wednesday February 4, 2015Due FridayHW#4 Forces in FluidsFORCES
UNIT EXAM Feb 18-19Turn to LW #4: Bobbin for Buoyancy and complete
the Analysis and conclusion questionsData Analysis:Draw a picture
to demonstrate each of the buoyancies (positive, negative and
neutral) Add arrows to represent gravity and buoyant force.Describe
what happened to the film canisters buoyancy as you increased the
mass. AnnouncementsAccepting donations for the Edible density lab
$28 needed for your class to participate. DEADLINE IS FEB 12Quiz
next Wednesday- not open noteFORCES UNIT EXAM- FEB 18- 19
Notes #2: Buoyant Force
1. WHAT IS A FLUID?Any material that can flowALL liquids and ALL
gases are fluids.
4
This upward forceIs CALLED BUOYANT FORCEgravityWater
pressureWater pressure52. WHAT IS DISPLACEMENT?
Displacement= taking the place ofThe egg displaces, or moves100
ml of waterArchimedes Principle
The weight (in Newtons) of that displaced water is the objects
buoyant forceDo demo with empty and full film canister
displacement
4. What is the relationship between buoyant force and
displacement?
AN OBJECT WILL FLOAT IF IT WEIGHS LESS THAN THE FLUID IT
DISPLACES
Positive buoyancy
4. What is the relationship between buoyant force and
displacement?
AN AN OBJECT WILL SINK IF IT WEIGHS MORE THAN THE FLUID IT
DISPLACES
NEGATIVE buoyancyUSE THE TERMS WEIGHT, DISPLACEMENT,. USE ARROWS
TOO!
This beach ball floats.Why?
It floats because it weighs less than the water it
displacedWeight of ball(gravity force)Buoyant force
WEIGHT OF OBJECTBUOYANT FORCE: weight of the water that was
displacedTHE BIGGER FORCEWINS, SO THE BLOCKSINKS
Which one is easier to pick up?Why?
Why?Because the ships shape causes it to displace more
waterWHICH ONE IS MORE LIKELY TO FLOAT?WHY??????BAMass = 90 kgMass
= 90 kgInsert titanic clip here
