1. Unit 2
Floating and Sinking

2. Forces A force is a push or pull.
The Newton is the unit of measure used to determine the strength of a force.

3. Gravity Gravity is a force that pulls objects together.
Weight is the measure of the force of gravity on an object.
Spring scales are scientific tools used to measure weight.

4. Buoyant Force
Buoyant force is the upward force acting on an object submerged in a fluid.
Hydrometers are scientific tools used to measure the density of a liquid relative to water.
All fluids, including air, have buoyant force.

5. Displacement
Displacement happens when a fluid is pushed aside to “make room” for an object or substance.

6. Density
Density is a measure of the amount of matter (stuff/particles) in a mass of an object.
The closer the particles of a substance, the higher the density.

7. Archimedes’ Principle
Greek mathematician Archimedes determined the relationship between density and buoyancy.
The buoyant force of an object submerged in a fluid is equal to the weight of the fluid displaced.

8. Float or Sink?
Whether an object sinks or floats depends on the weight of an equal volume of the fluid it displaces.
To predict whether an object will sink or float you must compare the density of the object to the density of the fluid it displaces.