Buoyant+Force

In this activity you will determine the maximum weight that a bobber can float.

Buoyant force is what makes an object float. When an object is put in a fluid, it displaces some of the fluid. The buoyant force on an object is equal to the weight of the fluid that the object displaces. This is why, for an object floating on a liquid, the weight of the displaced liquid is the weight of the object.

Understanding floating requires an understanding of density. Remember, density equals mass divided by volume. Objects with a lot of density have a high mass in a small volume like a pound of lead. Objects with little density have a low mass in a high volume like a pound of feathers. The relationship between the density of an object and the density of a fluid will determine the buoyancy of the object.

Here is how density is related to floating: When the density of an object is less than that of a fluid, the object will rise in the fluid. When the density of an object is more than that of a fluid, the object will sink in the fluid. When the density of an object equals that of a fluid, the object will neither rise or sink in the fluid. The above shows that the buoyancy of an object can be determined by comparing the density of an object to the density of a fluid.

Here is how buoyant forces is related to floating. The weight of an object that rises in a fluid is less than the weight of the fluid displaced. The weight of an object that sinks in a fluid is more than the weight of the fluid displaced. The weight of an object floating in a fluid is equal to the weight of the fluid displaced. The above shows that the buoyancy of an objects can be determined by comparing the weight of an object to the weight of the fluid it displaces.

From the above we can see that less dense objects have more buoyant force in relation to their weight and more dense objects have less buoyant forces in relation to their weight.

The amount of fluid displaced by a cylinder is equal to the volume of the cylinder in the fluid. Water has a density of 1g/cm^3, so one gram of water has a volume of 1cm^3.

Archimedes' Principle: "Any object, wholly or partially immersed in a fluid, is buoyed up by a force equal to the weight of the fluid displaced by the object." – [|Archimedes] of [|Syracuse]

A water-line is the level reached by the water on the side of a floating object.







Related: If Ice is made of water, why does it float? Galileo’s primary argument for floating ice was correctly based on Archimedes’ density theory, wherein an object in water experiences a buoyant force equal to the weight of water it displaces. Because ice is less dense than liquid water, it will always float on liquid water. The reason ice floats on water has everything to do with density. Ice is a rare example of a solid that is less dense than its corresponding liquid. Other examples of matter possessing this curious oddity are arsenic, bismuth, gallium, and silicon.

http://hyperphysics.phy-astr.gsu.edu/hbase/pbuoy.html http://www.seaperch.org/article?article_id=313 http://seaperch.mit.edu/science_buoyancy.php https://seaperch.byu.edu/wp-content/uploads/2013/06/Final-Paper.pdf How might these devices work similarly? http://www.discovery.com/tv-shows/mythbusters/videos/amphibious-bike-minimyth/ []

Lego https://youtu.be/wEvtahSn_ms TED1 https://www.youtube.com/watch?v=0v86Yk14rf8 TED2 https://www.youtube.com/watch?v=ijj58xD5fDI

https://www.youtube.com/watch?v=sw66gzBD9fE https://www.youtube.com/watch?v=dMvfv3aDa0E