Buoyant Force and Archimedes Principle

Multiple Choice

The upward force exerted by a fluid is called the...

• buoyancy force

• density force

• fluidity force

• normal force

Archimedes Principle

Mrs. Fuller
8th Grade Science

Multiple Choice

What is a buoyant force?

• The force that makes an object sink

• The density of the fluid an object is submerged.

• An upward force exerted on an object by a fluid.

• The depth to which an object is submerged in a fluid.

Multiple Choice

How do steel ships float, even though steel is denser than water?

• Boats are not made of steel

• Boats can only float in salt water

• The density of the steel is reduced by hollowing out the boat to increase its volume.

Multiple Choice

_______________ says that the weight of a fluid that is displaced by an object is equal to the buoyant force acting on the object.

• Archimedes Principle

• Aristotle's Equation

• Aristophanes' Cloud

• Anaximander's Apeiron

Multiple Choice

I place an object made of an unknown substance into a bucket of water and it sinks. The object must be _________ dense than water.

• less

• more

Explanatory video

https://www.youtube.com/watch?v=16HDJNoXQII

Multiple Choice

If the density of an object is greater than the density of water, it will

• sink

• float

• fly

Multiple Choice

If an object sinks in a fluid, _____.

• the density of the fluid is greater than the density of the object
• the density of the fluid is less than the density of the object
• the density of the fluid is equal to the density of the object
• density has nothing to do with whether an object sinks or floats, only which state of matter the object is

​Archimedes Principle

​The Archimedes Principle says that the weight of the fluid that an object displaces is equal to the buoyant force acting on the object. In other words, the more water an object displaces, the more the water was pushing back on the object as it submerged.