# TE 401 Lesson Plans: Fall, 1997

### Instructional Representation for Buoyancy

EPE Type

Student Personal

Scientific

Qualitative

Scientific

Quantitative

Experiences

(Observations,

Data)

Everyday experiences with floating and sinking

Impressions of weight

Comparing amounts of liquids by pouring

Comparing mass and density: Systematic observations of floating and sinking, varying volume, mass and density of solids and liquids

Measurements of weight and volume of different materials to calculate density

Measurements of weight of objects suspended in fluids

Measurements of pressure at different depths in fluids

Patterns

(Generalizations,

Laws)

Objects have two general properties: heaviness and amount

Gases weigh less than liquids and solids

Heavier objects sink, light objects float

Air does not make heavy objects float

Weight/mass, volume, and density are separate properties

Whether objects or fluids float or sink depends on relative densities

D = m/v

Archimedes’ principle: Buoyant force equals volume of object times density of medium.

(Weight equals volume of object times density of object.)

Application

Inquiry

Explanations

(Theoretical

Models)

Floating and sinking and balances both compare “heaviness” of objects/materials

Buoyant force is caused by difference in pressure on the top and bottom of an object (or part of fluid)

Pressure equals weight of fluid above the point where it is measured