1. Whatever floats your boat!
Floating and Sinking
Whatever floats your boat!

2. Measuring Objects
Anything considered to have matter has mass and takes up space.
Mass – amount of ‘stuff’ or matter in an object.
Volume – amount of space something takes up

3. Calculating Density To calculate mass – triple beam balance or scale
Units = g or kg
To calculate volume – length x width x height, or graduated cylinder.
Units = cm3 or ml
To calculate
Density = MASS
VOLUME
Units = g/cm3 or g/ml

4. Sinking or Floating
In order for something to float, it must be less dense than the fluid in which it is immersed.
Density of water = 1.0 g/cm3
Example: oil and water
Layering on page 425 of textbook
If density is less than water it floats
If density is more than water it sinks
Change pg# on notes
Demo: Oil and Water

5. Sinking If an object is more dense than the liquid, it will sink
Ex: lead, steel, fishing weight, etc…
Submarine can change it’s density by taking in, or pumping out water.
Ex: Cartesian diver.
Needs to be a class eyedropper
Fill to top with water
Squeeze to increase pressure and
Demo: Cartesian Diver
Brainpop: Submarine

6. Buoyancy
Buoyancy is the upward force produced by a fluid that acts on an immersed object.
Ex: boats floating, figure 10, p. 427 – jellyfish, turtle, and lobster
A fluid exerts pressure on all surfaces of a submerged object.
Since pressure increases with depth, the pressure acting on the bottom of the object is greater.

7. Archimedes Principle
Archimedes's Principle: The buoyant force is equal to the weight of the liquid displaced.
Immersion:  all or part under water.
Submersion:  completely under water
Demo: Clay sinks and floats
Brainpop: Bouyancy

8. Measuring Buoyant Force and Volume of Solids
To measure buoyant force – must measure weight of water displaced in Newtons.
To measure volume of irregular shaped object: it is equal to volume of water displaced.

9. Amount of Buoyancy
Buoyant force is determined by the density of the fluid and the density of the object.
More dense fluid = more buoyant force
Ex: salt vs. fresh water
Less dense object = higher the object floats.
Density also changes with heat Hot water is less dense than cold water. Hot air less dense than cold air. This is why cold air sinks, hot air rises.