ANDREW LAMBERT PHOTOGRAPHY / SCIENCE PHOTO LIBRARY ANDREW LAMBERT PHOTOGRAPHY / SCIENCE PHOTO LIBRARY
Polystyrene in water. Image 2 of 2. It has been pushed under the surface of the water, and is thus displacing an amount of water equal to its volume. Were it not being pushed under, it would displace a volume of water with the same mass as the block. As this is less than the volume of the block, the block floats. Objects with the exact same density as water displace the same volume. If they are denser, the volume of water displaced is greater than the object's volume, and it sinks. Image A350/196 shows the block floating naturally. Note the water level is around 770 millilitres here.
Model release not required. Property release not required.