- The specific gravity of steel is 7.8, yet steel battleships can float. How can this be?
Due to Archimedes’ principle, there is an upward force on the ship, which is equal to the weight of the water it displaces. The boats interior is made of air; therefor the average density of the ship is very light compared to the waters density it is submerged in. Only a fraction of the boat is in the water. Boats do have weight limits, like we have seen in class. We saw a picture of a cargo ship that looked like it was barely afloat because of the heavy load put in it, but still the average density of the ship was less than the density of water, causing the ship to float.
- Water expands when heated. Imagine a bobber floating in a cold pond. Will that bobber floathigher or lower in hot water? Assume the density of the bobber doesn’t change. Justify your answer using Archimedes’s Principle.
In the cold water, the bobber would float lower in the hot water than the cold water. The hot water’s molecules are moving very rapidly and are further apart, allowing a bobber to sink. In cold water the molecules are very close together, which would hold the bobber up higher.
- Web Research Question: Visit this webpage for a thorough discussion of Archimedes and the crownstory:http://www.math.nyu.edu/~crorres/Archimedes/Crown/CrownIntro.html this page debunks the notion that Archimedes solved the crown problem by measuring its volume by displacement. First, explain in your own words why it’s not very plausible that Archimedes could have exposed the thief by measuring the volume of the crown through water displacement. Then find at least two web pages that explain the crown story the wrong way and paste quotes from them into your answer, along with their URLs. Explain why you think this scientific myth has persisted over the years.
When Archimedes place the crown in the bathtub to measure its total displacement, he noticed a change in water displacement between the 1000 gram crown and the 1000 gram pure gold bar. We now know that the difference in water displacement is so small, the human eye could not depict the difference.
Realizing he has hit upon a solution, the young Greek math whiz leaps out of the bath and rushes home naked crying “Eureka! Eureka!” Or, translated: “I’ve found it! I’ve found it!” Several millennia later, the scientific world is replete with the exclamation, and many people have received inspiration in the shower. – http://www.scientificamerican.com/article.cfm?id=fact-or-fiction-archimede
https://www.britannica.com/place/Dead-Sea
https://www.youtube.com/watch?v=TDEzBWjQpQI
-These both are about the Dead Sea and how easy it is to float. The first describes it and then the second link is a video to see how easy it is to float.
http://www.explainthatstuff.com/how-ships-work.html
-This link talks more about how boats and ships don’t sink.
https://physics.weber.edu/carroll/archimedes/principle.htm
-This link shows a good illustration how Archimedes principle works and talks more about the principle.
