Cartesian Diver Experiment

Cartesian Diver Essay
The Cartesian Diver is named after the French scientist Rene Descartes. This experiment is supposed to show buoyancy, density and different forms of matter at work, when demonstrated.
To create the Cartesian Diver, you’ll simply need:
• A empty plastic bottle
• A plastic eye dropper
• Water

1. Fill the bottle with water, but be cautious of spills.
2. Very carefully, drop the dropper inside the bottle. Then, seal the cap on very tightly.
3. Squeeze the bottle, but not too tightly.
Notice how the dropper sinks to the bottom of the bottle, but when you release your grip, the dropper floats back to the top. Why is that? There are certain forces that allow the diver to sink and float. They are:
• States of Matter
• Buoyant
It’s calculated by dividing the mass of the object by the volume. The average density of an object can determine if it’ll sink or float when submerged in liquid. The average density for water is 1.0g/ml. and if an object with the average density greater than 1.0g/ml, then it’ll sink. Vice versa, if the density is less than 1.0g/ml, it’ll float. For this particular experiment, when the bottle is squeezed, the air inside the diver is compacted, and the volume decreases. When there is a change in volume, there is also a change in density. When the density increases, the diver will sink. This is because water is denser than air. When pressure is applied to the bottle, the dropper fills with water. Since water is denser, this changes the overall density of the diver itself. Now the diver’s density is larger than the water, and sinks. The reverse can also be applied to this. When the water is released, the air can once again expand. The density then drops, and becomes lighter than water. Therefore it floats. Here is a diagram I found that shows this in
Solids have an assigned shape and volume, liquids have a volume but no shape, and gases lack both. In the experiment, when the bottle is squeezed, the air is also squeezed, and pressure exerted allows the liquid to push through. Liquids cannot be squished and compacted because they have volume and cannot become smaller, but gases can be compacted because they don’t have any volume. The dropper then fills up with water, and since it’s filled with more mass, it drops to the bottom because it’s now denser than the water surrounding it. When you finally release your hold, the water leaves the dropper. The gases once packed together can move around, and the dropper is now lighter than water, so it floats back up. Positive buoyancy is where the density of the object is lower than 1.0g/ml, whereas negative buoyancy is the reverse. Neutral buoyancy occurs when the density of the object and water are equal. So, in hindsight it doesn’t float or sink. For example, if a plastic beach ball were to float in a pool, it would be positively buoyant.
In conclusion, I believe that these contributing factors are why the Cartesian Diver can function. The reason for the diver floating (positively buoyant) was due to the changes in volume and density, which let the buoyant force keep the dropper sustained; and when it sunk due to the decrease in volume of air. With the decrease of air, the volume shrunk, and the density had risen. Once