It decreases?

If the air pressure increased, wouldn't that make the diver go down? What happens when you press on the pressure cap?

Oh, yeah. So, at night the atmospheric pressure increases and therefore the diver sinks?

Can someone help me with this question about a Cartesian Diver:

You painstakingly adjusted the water level of your diver so he is just floating and your treasure is just sinking. You come back the next morning and find your diver sitting next to the treasure on the bottom of the bottle. Knowing that your bottle was tightly capped, how can you explain this?

I think the answer has to do with the level of the water in the diver. It must have changed. I don't really know why though.

What happened to atmospheric pressure overnight?

Why is the atmospheric pressure higher at night?

To answer these questions, let's start by understanding how the Cartesian Diver works. A Cartesian Diver is a simple experiment that demonstrates the principles of buoyancy and changes in pressure. It consists of a small, hollow figurine or diver that floats inside a partially filled bottle.

The key to understanding the behavior of the Cartesian Diver lies in changes in pressure. When you squeeze the bottle, you increase the pressure inside, compressing the air trapped in the diver. As a result, the volume of air decreases, making the diver dense enough to sink. Similarly, when you release the pressure on the bottle, the air inside the diver expands, displacing more water and causing it to float back up.

Now, let's address your specific questions:

1. If the air pressure increased, wouldn't that make the diver go down?
- Yes, you are correct. If the air pressure were to increase, the air inside the diver would compress, making it denser and causing it to sink.

2. What happens when you press on the pressure cap?
- When you press on the pressure cap, you apply external pressure to the bottle. As a result, the air inside the diver compresses, and it sinks.

3. So, at night the atmospheric pressure increases, and therefore the diver sinks?
- No, the atmospheric pressure does not directly cause the diver to sink. Atmospheric pressure refers to the pressure exerted by the Earth's atmosphere on its surface. While atmospheric pressure can vary, it is not the primary reason for the diver sinking or floating in the Cartesian Diver experiment.

Now let's address your question about the diver sinking overnight.

When a Cartesian Diver is tightly capped, the amount of air trapped inside the diver remains constant. However, changes in temperature can affect the pressure inside the bottle. In general, as the temperature decreases, the pressure of the air inside the bottle decreases as well.

If the temperature inside the room dropped overnight, the air pressure inside the bottle would also decrease. As a result, the pressure acting on the surface of the water inside the diver would be reduced, causing the water to push up on the diver less. This change in pressure would make the diver less buoyant and allow it to sink.

Therefore, the sinking of the diver overnight can be attributed to the decrease in pressure caused by a drop in temperature, rather than changes in atmospheric pressure.

I hope this explanation clarifies your questions about the Cartesian Diver and the factors affecting its behavior.