Wheels, gears, cogs...anything that needs to be endless.

Captain Edward Smith. The captain of a big ship like the Titanic ship does not actually steer the ship himself. He has a crew that does that under his instructions. So he was not actually "driving" the ship at the time of the accident. He was still ultimately responsible though because its the captains job … Read more

This is not known. I'd say it was the first guy who discovered he could hollow out a log and sit in it while catching fish or travelling down a river. See article on "dug-outs". en.wikipedia.org)

It is used to determine the weight (mass) of a ship. There are no scales big enough to weigh a ship so what mariners do is calculate the volume of the underwater section of the hull of the ship (length X breadth X height) approximately. The (average) density of sea-water is known (1025 kg/m3). We … Read more

Because if it didn't it would kill the fish, crabs, turtles and other creatures that live underwater. This most fortuitous for our aquatic friends because other substances (like metals) become more dense when they change phase and  go from liquid to solid form.  Water is special because when freezes it becomes less dense than when it … Read more

Perception can be described as the way reality is seen by the individual. Perception can be accurate, partially accurate/ distorted or completely incorrect.  Someone's perception of anything can be influenced by various factors including previous experiences, education, maturity, emotional state and cultural, religious and personal biases.