Answer :
because they have no dignified shape they take on the shape of whate ever container they are in and when you pour in out it can't really take any shape except tho lay flat on the table. and solids do not flow because they have a dignified shape. hope it helps!
The reason that solids are not able to move freely is because their structure and "lack of" energy they stay together from it mutual bonds. Liquids are able to move freely because they are moving ever so slightly and there bonds are weaker than of a solid, allowing the liquid molecules to slid past each other.
