Physics Ili

Floating Ball Game - Demonstrates Bernoulli's Principle - Law of Pressure Differential -- Another classic science toy that is not only fun but teaches real scientific concepts. Made of wood. Comes with two styrofoam balls. See how long you can make the ball float. Challenge family and friends. Great party favor or holiday gift. -- The floating ball game is an excellent example of "Bernoulli's Principle". As air is forced around the ball it must move faster in order to "catch floating ball game up" on the other side. The result is a decrease in air pressure around the ball that in turn keeps the ball in place. The force is strong enough to resist other forces acting on the ball such as a subtle tap from your finger. The force can also overcome gravity if the flow of air is strong enough. This can be demonstrated by turning the base of the pipe 15-20 degrees - the ball will remain suspended in the air flow even though it is not directly above it. Give it a try and see what you can discover!

What do a flying airplane and a pitcher's curve ball have in common? Well, besides the fact that both travel through the air at amazingly fast speeds, both are based on a principle called Bernoulli's principle. Bernoulli (pronounced Burr New Lee), was a Swiss mathematician who liked to piddle around with these types of things.

Archimedes`principle

The letter scale uses Archimedes's principle to weigh letters. A graduated cylinder of pyrex glass is floating in liquid. The weight of the letter pushes down the upper cylinder, thus causing the liquid to rise in between the two cylinders. The movement is thus measured and transferred into weight units.

Pascal`s principle

Pascal's Principle Pressure is transmitted undiminished in an enclosed static fluid.

Any externally applied pressure is transmitted to all parts of the enclosed fluid, making possible a large multiplication of force (hydraulic press principle). The pressure at the bottom of the jug is equal to the externally applied pressure on the top of the fluid plus the static fluid pressure from the weight of the liquid.

Atmospheric pressure

Gas pressure

Static Fluid Pressure

The pressure exerted by a static fluid depends only upon the depth of the fluid, the density of the fluid, and the acceleration of gravity. The pressure in a static fluid arises from the weight of the fluid and is given by the expression

Pstatic fluid = ρgh

ρ = m/V = fluid density where g = acceleration of gravity h = depth of fluid

The pressure from the weight of a column of liquid of area A and height h is

The most remarkable thing about this expression is what it does not include. The fluid pressure at a given depth does not depend upon the total mass or total volume of the liquid. The above pressure expression is easy to see for the straight, unobstructed column, but not obvious for the cases of different geometry which are shown. Because of the ease of visualizing a column height of a known liquid, it has become common practice to state all kinds of pressures in column height units, like mmHg or cm H2O, etc. Pressures are often measured by manometers in terms of a liquid column height.

DEFINITIONS Pressure : a force, F normally to the surface with an area, A will result in a pressure, P which can be defined as P = F/A. Gas press. : a force per unit area exerted by the gas particle as they collide with the walls of their container. Pascal’s principle : can be stated as F1/F2 = A1/A2 where F1 is the force supplied (N), F2 is the force produced (N), A1 is the area over which the original force is applied (M squared), and A2 is the area over which the produced force is applied (M squared) Archimedes’ principle : state that the buoyant force on a body immersed in a fluid is equal to the weight of the fluid displaced by that object

Bernoulli’s principle : relates the pressure of a moving fluid with the speed at which the fluid is moving.