It was really boring. For around 45 minutes the professor tried to explain why pressure throughout a liquid of same depth is constant. I wanted to sleep, but it would seem rude
However, the applications and demonstrations of hydrostatic pressure were rather interesting, yet simple.
1) Land surveying
With a main water tank and pole filled with water connected to the tank with a hose, altitude at which the pole is can be read via markings of the pole. Of course we have to make the water in the tank a lot compared to that in the connecting tube and the pole, so that the change in datum (water level in the tank) is negligible.
2) Hydraulic jack
I always thought that hydraulic jacks were gigantic pieces of equipment controlled by machines, because the great difference between the force humans apply and the weight of the truck is so large, in order to gain sufficient mechanical advantage, one will have to go to the top of the empire state building, hold onto a handle of the same height, and jump off the building in order to lift anything. Turns out that I had the wrong idea. People wouldn't be that stupid. Instead they suck hydraulic liquid from another chamber when needed, so we can push the pump back and forth, drawing liquid and pushing it, instead getting a darwin award.
3) Siphon. Water sucker. Found out about the siphoning effect years ago, but never really thought about how it worked.
4) Magdeburg Water bridge.
As one walk across a conventional bridge, center of mass shifts from one pillar to another. However, in a water bridge, pressure throughout the fluid remains the same, so assuming that there is little turbulence, the force is always evenly spread out across all pillars.
Magdeburg Water bridge
A water bridge in Germany, 918 metres long, the longest aqueduct in whole of Europe. It has been planned for 80 years, but put off after the splitting of East and West Germany. Now, it is used to connect Berlin's inland harbour and ports along the Rhine.
5) Lastly, we were given the task of coming up with a design for a fish tank which allows people to put their hand through a hole at the side to touch the fish. I heard of something like that in Underwater World in Sentosa sometime ago. However I found nothing when I searched the internet. Even went to Yahoo answers, but people gave me useless answers like reach your hand from the top, or have a pump that continuously pumps water back in as it spills out.
Here are some more ideas.
1) Vortex. Vortex tank creates a vortex in front of the opening like a washing machine, so the water does not spill out. Reaching your hand inside might disturb it though, so this 'reach in tank' is a see no touch
2) Plastic gloves. Transparent gloves makes it look as if your hand is reaching in. Gloves are coloured in picture for easier viewing. You can't feed to fish in here, because fish food does not pass through plastic.
Any more ideas on how this might work?
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