sink
A styrofoam cup will float in water because styrofoam is less dense than water, causing it to displace water and float.
The piece of Styrofoam will float, the piece of oak will sink, and the gold ring will also sink. Styrofoam is less dense than water so it floats, while oak and gold are denser than water so they will sink.
Pumice rock will float unless water fills most of the small air pockets. Wood may also be dense enough to sink when waterlogged. Styrofoam and similar materials cannot sink because they are less dense than water.
The property that separates styrofoam balls is their buoyancy. Styrofoam balls are lightweight and have air trapped inside, making them less dense than water. This causes them to float on the surface of water, separating them from denser materials that sink.
put water in to let it sink... then put air into it to let it float...
Air resistance.
The same piece of foil can float or sink depending on its shape and how it is positioned in the water. If the foil is shaped to trap air, it will float. If the foil is crumpled or folded so it doesn't trap air, it will sink.
That will depend on the size of the styrofoam pieces. If they are significantly larger than the sand, you merely pick them out by hand. If not, then a sieve can be used assuming the sand will go thru the sieve and the styrofoam will be too large to pass through. You need to find a sieve with the right size holes. Another way is to add acetone and the styrofoam will dissolve, and the sand will stay behind, but this technique doesn't give you the styrofoam back again.
Styrofoam will float indefinitely because it is less dense than water, making it buoyant. This is due to its composition of trapped air bubbles within the material, preventing it from sinking.
An Orange with a Skin on will Float- Air will be trapped inside the skin, but an Orange without the skin on, although lighter, has no air trapped, and will, in turn, sink.
A ship loaded with a cargo of Styrofoam would rise higher in the water compared to if it were empty. Styrofoam is less dense than water, so it provides buoyancy and causes the ship to float higher in the water.
Styrofoam is very buoyant because it is mostly made up of air trapped within its closed-cell structure. This air makes styrofoam extremely lightweight, allowing it to float easily on water.