# Does enclosed water act like a solid?

Because water is non-compressible, a container filled with water doesn't react like a container filled with air would (e.g. deforming in response to impacts etc.), or even the way a container half-filled would. So, does it act the same as a solid?

I don't know any physics, so please explain like I'm an Arts major.

• Water (and other liquids and solids) are compressible, just not as much as gases. A liquid-filled object will not behave exactly as a completely solid object because of the possibility of dissipation in the liquid. – Jon Custer Aug 18 '17 at 15:49
• @JonCuster Mechanical dissipation will also occur in the solid due to internal friction. However, at least two other things will differ between containers filled with a solid vs. a liquid: the liquid will not resist a shear load on the container, and natural convection will occur in the liquid if a temperature gradient (and a gravitational field) exists. But in any case, I agree that the premise of the question is incorrect because water (and all liquids and solids) are compressible, as quantified by the bulk modulus. – Chemomechanics Aug 18 '17 at 16:02
• Imagine a plastic bag filled with liquid. Does the behave like a solid? Imagine the plastic bag half-filled with liquid. Same question. – Chet Miller Aug 18 '17 at 16:25
• There will also be the following difference: if you rotate the bottle along its axis, the water inside will also rotate. If you stop the rotation, the water will still move for a while since its adherence to the bottle is weak. This woudl not happen with a solid object: in this case every part of the object will stop, but you'll need more force to stop it. – EigenDavid Aug 21 '17 at 9:25
• @Benubird - Take two bottles completely full of water, one frozen and one liquid. Place them on a flat surface and then lower a flat plate with a significant amount of mass onto each bottle. Once at rest, move the top plate parallel to the flat surface on which the bottles rest. The bottle with the liquid water will likely rip apart and explode while the ice-filled one will slide against one of the plates (assuming not too much mass on top plate). – honeste_vivere Aug 21 '17 at 14:31