Archimedes´ principle

The question of why some objects sink
in fluids while others float can be
answered using the law of buoyancy.
This law is known as Archimedes'
principle, after the ancient Greek
scientist who discovered it.
Archimedes Principle
It can be expressed as ‘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.
 According to a tale, Archimedes
discovered this law while taking a bath.
After making this discovery, he is said to
have leapt out of his bathtub and ran
through the streets of Syracuse naked
shouting "Eureka!".
If the weight of the water displaced is
less than the weight of the object, the
object will sink
An object will float, with the weight of the
water displaced equal to the weight of
the object.
It states that "any body partially or
completely submerged in a fluid is
buoyed up by a force equal to the weight
of the fluid displaced by the body.
 " The weight of an object acts
downward, and the buoyant force
provided by the displaced fluid acts
upward. If these two forces are equal,
the object floats.
If you’ve ever tried to push a beach ball
underwater, you’ve felt this principle in
 As you push the ball down, it pushes
back up. In fact, a big beach ball can be
tough to hold underwater. As a physicist
in a bathing suit, you may wonder,
“What’s happening here?”
1. Who discover the principle of buoyancy?
2. How did he come up with the conclusion?
3. Explain the principle and use 3 examples,
with graphics.
4. What´s the opposite force to gravity (acts
5. Is it the same if you talk about a ship with
cargo or empty? Yes /no? why?
6. g______, b_____ and density work together
to determine what floats your boat, or sinks
your ship