Water & Air

The world consists of five elements: Fire, Water, Soil, Aerial and ether. The first four are out of earthly nature. The fifth fills the sky. – Aristotele

Buoyancy

Objects seem lighter under water than in air, although the mass is the same! At the station “Boost” you have to pull up the ball in- and outside the water. In the water the buoyancy counteracts with the weight force- so the ball seems lighter.

Cartesian Diver

The cartesian diver exists in the main focus out of a transparent tube, which is filled with water. A small bottle, which contains air and is set on the top, can decline and move up in the fluid, by changing the pressure. In the starting position it swims on the upper end of the cylinder. When you raise the pressure over the pedal, the air bubble in the object is pressed and the boost is reduced; the bottle declines. Decreases the pressure, the object moves up.

Coke Light

The boost of an object, which is immersed in fluid, relates to the volume of it. By an object with lower density than the fluid, the boost is enough to prevent the decline. With higher density it declines. On a iron are one litre bottles with coca cola and coca cola light hanged up, which you lower in the water basin. The cola- light bottle swims, because the small air bubble in the bottle gives enough boost. In contrast the bottle with cola drops, because it contains much sugar (106 gram per litre!) and so, it has a clearly higher density than water!

Coriolis Fountain

A vivid phenomenon with water! Water out of a horizontal in circle led nozzle, which aims to the rotation axis, takes part, by going through the nozzle, on the moving and is picked up in this direction. Thereby the water splashes not exactly to the rotation axis, but in direction of movement besides. Water, which splashes from the rotating axis away, is also picked up in the direction of movement. Far off from the axis it ought to be faster, to keep up with the rotation, because on the outside means a longer way than on the inside. Because the water is exposed by leaving the nozzle, it keeps his speed and is left behind.

Floating Ball

It is really mysterious, how the ball floats in the air flow and does not fly away, drops down or pulls out to the sites. Through the free access you can experience the phenomenon easily, by turning the blower or affecting the air flow with your hands. Responsible for the phenomenon is the little pressure in the flowing air. On a in the flow situated area impinges a smaller power on the surface, So, the ball, comparable with a aircraft wing, experiences a boost.

Geyser

Like in the striking and famous nature phenomenon, water fountains are splashing powerful and without advance warning upward. When the water in the piston is warm enough it occurs gas. The higher the boiling point in the piston, the higher the created pressure. When it is high enough, the hot water shoots upwards. But when it faces the cold water in the bowl, the fountain splashes upwards.

Globe of Flows

The acryl ball is filled with a special fluid, which show the swirls, increasing by the rotation in the inside of the ball, very good.

Iceberg

Our iceberg modell shows clearly and aesthetical, that just the head of the berg can be seen, while ca. 85 percent of the whole iceberg is under water. By approximation just the top of the berg is visible. After pushing the button the lightning and transparence of the blue foil is activated. Now you can see the big part of the iceberg under water- beautiful illuminated!

Parabola

On the basis of the centrifugal force strives the fluid from the rotation axis away, when you give downturn to the container. The surface is the lowest on the rotation axis and raises parabolic to the outside- the higher the rotation, the steeper. In each variety (containers filled all around or just in a separate slit) this is a beautiful phenomenon, which needs action first!

Paraboloid

On the basis of the centrifugal force strives the fluid from the rotation axis away, when you give downturn to the container. The surface is the lowest on the rotation axis and raises parabolic to the outside- the higher the rotation, the steeper. In each variety (containers filled all around or just in a separate slit) this is a beautiful phenomenon, which needs action first!

Ripple Basin

Swirled water can create a waving structure on a sand subsoil. The smallest irregularities in a first even sand subsoil increase, because the water moves the sand particles away from the even sand areas and stay preferably, where other particles are already gathered. In a hung basin is little sand, which is ca. 2 mm high covered by water. When you swing the basin softly, you create wavelike structures in the sand- like in flat water on the coast.

Rising Bubbles

It is fun to pump air in the viscous fluid- maybe together, because the pump is kind of stiff to use. Now you can watch the bubbles calmly- their “passing manoeuvre”, collision and their fusion! The bigger the gas bubbles, the faster they move up in the fluid, because with increasing size grows the boost faster than the flow resistance. So, the flow phenomena are impressive visualised- an aesthetical pleasure!

Sandrifuge

When you turn the glass container, which is filled with sand, there increase beautiful, sensual patterns. By different speeds or abrupt stopping the visitor can create new images over and over again.

Sedimentation Tubes

When the frame is turned, the sand declines downwards through the water and you can watch and compare the different sink speeds. The four tubes are filled with water and different coarse sand. A big grain of sand sinks fast in the water- when you crumble it in many small grains they sink slower. By the big cross-sectional surface, the flow resistance raises, although the weight, which floats the sand down is the same.

Sinking Ship

Air bubbles in the water reduce the boost of a swimming object, because the water is so to say diluted with air and can not take it that good. The visitors pump air in the water. As soon as the bubbles face the boat, it declines. When it reaches bubble free water, it moves up.

 

Sticky Air

Surprising experiment: The from the top sluiced air ensures, that the plate on the opening “sticks”, because it increases a negative pressure. But: The plate has to be, against the pressure from the air close enough to the discharge opening, so the flow velocity is big enough and the pressure over the plate small enough to float free.

Tornado

Hardly perceptible air movements are strengthened, when air approaches the rotation axis of a tornado- like a pirouette. Raises the air in the rotation axis, more air comes in and the rotation is reinforced. A broad slit in the cylinder gives the opportunity, to influence the near hose by blowing or with hands and to study its reaction to this disturbs.

Vacuum Fountain

Water can flow in a hose in parts upwards, when it moves overall from a higher to a lower water level. Out of an open reservoir with a high-water level the water raises in the upper container, generated by a nozzle and flows down in the second container. The fountain is powered by the different water levels in the flooding and the drained container. When the water levels are the same in both of the lower containers, the well dries up. With a hand pump you can transport the water back and the original difference in level is rebuilt.

Water Bend

The so- called optical density from water is bigger than the density from air.  This circumstance leads, that by transition from water to air the light is distracted (refraction) from its original direction- it runs flat or is even reflected. When you look to a dived in object through the surface of water it seems, under a flatter angle, that there is no water. So, it is apparently raised. An oblique in the water immersed rod seems to have a bend at the surface of the water, because the part under water appears raised.

Water Bouncing Bowl

In the end- modern physics and old teaching of wisdom in unison- is all a “surge”. As well in this bronze water carapace, which is filled up to two thirds with water. When you rub over the two grips with damped handy, it is set in vibration. Manifested audible in a tone a many little fountains on the water surface.

Water Net

Basic rules: Cohesion (and the by that created surface tension) holds fluids together, by adhesion they stick to surfaces. When two on each other laying plates are pulled apart and between them is a little fluid, the wetted area contracts, because of the bigger distance you got more amount, so you don`t need that much space on the sides. But the adhesion does not want to release and it comes to an interesting interplay between adhesion and cohesion. This leads to fascinating filigree structures.

Wave Pool

Waves are familiar to us by many experiences- but the direct observation in nature is just hardly possible. In the aesthetic wave pool the visitor can watch the movements easily. The stratification of two fluids slows the motion sequences down, so the development and the spreading of the waves can be tracked easily. When you tilt the pool in the right moment and the energy is phase right supplied, the waves develop to breaking, which behave like those in the nature.

Whirlpool Cylinder

Here arises a funnel-shaped indentation, which can reach far down by high rotation speed as a thin pipe. The centrifugal forces let the rotating fluid strive from the rotating axis away. As the container does not rotate with the water (like in the paraboloid), the rotation in the middle of the cylinder wall is faster by the friction of the water- the centrifugal forces work the most in the middle.

 

Windtable

Test one of the flying objects. How long can it float?