Sink or Float

Front

Weight Noun

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[wayt]

Back

Weight

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A measure of the force of gravity pulling down on an object, which determines how heavy it is.

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Example: An object's mass (the amount of matter) stays the same everywhere, but its weight (the force of gravity on it) changes depending on the planet's gravity.

Front

Buoyant Force Noun

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[boy-uhnt fors]

Back

Buoyant Force

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The upward force that a fluid exerts on an object placed in it, which counteracts the object's weight.

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Example: This diagram shows an object in a fluid. The upward buoyant force opposes the downward force of gravity, determining whether the object will sink or float.

Front

Buoyancy Noun

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[boy-uhn-see]

Back

Buoyancy

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The ability of a fluid to exert an upward force on an object that is immersed within it.

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Example: This image shows that some objects, like pumice, float because the upward buoyant force is strong enough, while others, like obsidian, sink.

Front

Fluid Noun

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[floo-id]

Back

Fluid

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A substance, such as a liquid or a gas, that has no fixed shape and can flow to conform to its container.

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Example: This image shows that in liquids and gases (fluids), particles are not in fixed positions and can move past each other, unlike in a solid.

Front

Pressure Noun

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[presh-er]

Back

Pressure

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The force exerted on a surface per unit area, which in fluids increases with greater depth.

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Example: This diagram shows that as water depth increases, the pressure it exerts also increases, forcing the lowest jet of water out the farthest.

Front

Archimedes' Principle Noun

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[ar-ki-mee-deez prin-suh-puhl]

Back

Archimedes' Principle

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The principle stating that the buoyant force on an object is equal to the weight of the fluid it displaces.

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Example: This diagram shows a submerged object experiencing an upward buoyant force. This force is equal to the weight of the water the object displaces.

Front

Density Noun

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[den-si-tee]

Back

Density

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The amount of mass contained in a given volume, indicating how tightly matter is packed within a substance.

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Example: This image shows that liquids with different densities, like oil, water, and honey, will separate into layers, with the least dense liquid floating on top.

Front

Mass Noun

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[mas]

Back

Mass

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The amount of matter contained within a physical body, which is a fundamental and constant property of the object.

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Example: This image shows a triple-beam balance measuring the mass of a beaker and liquid, demonstrating how to find the amount of matter in an object.

Front

Volume Noun

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[vol-yoom]

Back

Volume

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The amount of three-dimensional space that a substance or object occupies or that is enclosed within a container.

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Example: This diagram shows how to measure the volume of a liquid by reading the bottom of its curved surface (meniscus) at eye level in a graduated cylinder.

Front

Displaced Fluid Noun

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[dis-pleysd floo-id]

Back

Displaced Fluid

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The volume of fluid that is pushed aside when an object is partially or fully immersed in that fluid.

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Example: Placing a solid object into a container of water pushes the water level up; the amount the water level rises is the volume of displaced fluid.