Science 8 Ch 11 Sec 1-2

What two factors does pressure depend on?

1. force and 2. the area over which the force is exerted.

Some canoes have compartments on either end that are hollow and airtight. These canoes won't sink, even when they capsize. Explain why.

Because water cannot enter these compartments, the air inside them gives the canoe a greater volume while adding only slightly to the canoe's mass. This makes the canoe less dense than water.

What is the formula for density?

Density= mass/volume

Why must an astronaut wear a pressurized suit in space?

IN addition to providing oxygen, the pressurized suit balances the pressure outside and within the astronaut's body.

How can you use the density of an object to predict whether it will float or sink in water?

If the object's density is greater that that of water, the object will sink; if the object's density is less than that of water, the object will float.

How does the buoyant force affect a submerged object?

The buoyant force acts upward on a submerged object, making the object seem lighter.

How does Archimedes' Principle relate the buoyant force acting on an object to the fluid displaced by the object?

The buoyant force on the object equals the weight of the fluid displaced by the object.

How does atmospheric pressure change as you move up away from sea level?

atmospheric pressure decreases as you move away from Earth's surface.

Compare the change in atmospheric pressure with elevation to the change in water pressure in depth.

atmospheric pressure decreases with elevation, but water pressure increases with depth.

barometer

an instrument that measures atmospheric pressure.

How do fluids exert pressure?

each particle in a fluid exerts a force when it collides with a surface

fluid

is a material that can easily flow, thus can easily change shape.

pressure

is equal to the force exerted on a surface divided by the total area over which the force is exerted.

What is density?

it equals mass per unit volume

pascal

named after French mathmetician, it is a unit of pressure.

Archimedes' Principle

states that the buoyant force acting on a submerged object is equal to the weight of the volume of fluid displaced by the object.

buoyant force

the force that water and other fluids exert an upward force on the submerged object.

Since most of the weight of the atmosphere is above you, then why aren't you crushed by it?

the pressure that Earth's atmosphere exerts on the body is equal in all directions.