# This link shows images that could not be displayed on this post. http://umdberg.pbworks.

1. Now make a prediction for what you think the pressures would be if you turned off the atmosphere. Show how your calculations change from the previous case and test your prediction against the simulation, making another table and graph and explaining any discrepancies you find.

C. Discuss the significant figures shown in the sim. Why do you think they are showing six sig figs? That certainly seems like a lot. A tiny movement of your mouse, undetectable on the screen, is likely to change those last figures and those changes certainly wouldn’t be detectable on the graphs you drew for parts 1 and 2. Is there anything interesting that might be learned from changes in those last couple of decimal places? If two measurements disagree only in the last two places, should we consider them to be the same (up to positioning error) or is the difference important?

D. Now switch to the conical vessels — the ones chosen by this button — and fill them up to the top. Before making a measurement, make a prediction how the pressure in the two vessels will compare in the center of each cone, 1m down and just above the bottom. Which do you expect to be bigger and why? Now make the measurement, give the result, and discuss either: how you knew what the result was going to be if your prediction was correct, or, if your prediction was wrong, what went wrong with your thinking about what was happening.

E. Finally, switch to the “hydraulic lift” configuration shown by choosing this button. Here, putting a weight in a narrow channel of water would allow you to balance a heavier weight in a wider channel of water. But that’s not the way they’ve set it up. They have opened the machine to let us see how it works. The masses fit into the narrow channel without leakage. Grab the 500 kg mass and put it in the space (dotted box) in the narrow just above the surface of the water. It will slowly sink down, pushing the water up on the other side. Now add the two 250 kg weights on top so the total mass in the narrow channel is 1000 kg. Use the ruler to determine how much higher the water level is on the wide channel than on the narrow channel.They are not telling us the area of the two channels. Can you figure either or both of them out from the information that you have? If you can find whichever you can find. If you can’t explain why you can’t.