Lesson 2 Powerpoint

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Transcript Lesson 2 Powerpoint

Why Did the Titanic Sink?

How did this happen?

Need to know:

    Buoyancy Archimedes’ Principle Why do some things sink, while others float?

What Happened to the Titanic?

What is Buoyancy?

  The Greek scientist Archimedes (287 B.C. – 212 B.C.) discovered that objects floating in a liquid are supported by an upward force. Simply put, buoyancy is the ability of an object to float.

Archimedes’ Principle! Eureka!

    Archimedes discovered that the buoyant upward force on a floating object is equal to the weight of the liquid that the object displaces.

For example, if an inflatable boat is placed in water and 100 lbs of water is displaced, then the buoyant upward force MUST be 100 lbs of force.

Word equation: Buoyant force=weight of liquid displaced=loss of weight in liquid Also, BF=weight of object in air-weight in liquid

WHEW! That was a lot of information! Stick with me…..

So how can a ship float?

    A ship can float because it’s constructed with many air-filled chambers. Air, as we all know, weighs less than water So, the combined weight of the air and steel of the ship weighs less than the weight of the water displaced by the ship So, the ship floats!

So???

   So this principle determines what sinks and what floats If an object weighs more than the water it displaces, it will sink. Quarter vs. aluminum foil! They are both metal, so they should sink, right? MAKE A PREDICTION!!

Wow!

  The quarter sank because weighed more than the water it displaced! It is a solid coin The aluminum foil floated because of the air within it. Air weighs less than water!

     What Happened to the Titanic? It was Archimedes’ Principle!

The “unsinkable ship” was en route to NYC in 1912 On April 14, it struck an iceberg The collision ripped a huge hole in the hull of the ship, causing the air filled pockets to fill with water This added weight became greater than the buoyant force supporting the ship, so it sank. Rapidly.

About 1500 lives were lost

Let’s Sum it Up!

   An object sinks when the weight of the object is greater than the buoyant force that supports it (quarter) An object floats when its weight is less than the buoyant force that supports it (Aluminum foil) Archimedes’ Principle is that the BF=weight of object in air-weight of object in water or the BF=the weight of liquid displaced=loss of weight in liquid