In this unit, students investigate the phenomenon of buoyancy. From their experiences, they are introduced to the following concepts, skills, and attitudes.

• Several variables affect the buoyancy of an object.
• Water pushes up on both floating and submerged objects with a buoyant force; objects push down on the water.
• The buoyant force on large objects is greater than the buoyant force on smaller objects.
• The amount of water an object displaces is directly related to the object’s volume.
• Because of buoyant force, objects appear to weigh less when they are submerged.
• Objects that weigh more than the same volume of water sink; objects that weigh less than the same volume of water float.
• Salt water weighs more than an equal amount of fresh water.
• The buoyancy of an object varies with the density of the liquid.

• Observing, recording, and organizing test results.
• Applying previous experiences to make predictions.
• Creating and analyzing graphs.
• Calibrating a spring scale and using it to measure the magnitude of a force.
• Reading science materials for information.
• Communicating results through writing and discussion.
• Solving a problem that requires the application of previously learned concepts and skills.

Attitudes

• Developing an interest in investigating floating, sinking, and related phenomena.
• Recognizing the importance of repeating a test or measurement and comparing results.