Are the molecules of all substances in motion?

Every substance is made up of very tiny particles called molecules. A molecule is the smallest part of the matter that can exist independently and exhibits all the properties of that matter. For example, if we take a molecule of sugar, it will exhibit all the properties of sugar such as taste, shape, colour etc.
Molecules of different substances differ in size. Some are only few billionths of a centimeter in size while some other molecules are thousands of times larger. Molecules of gases are small in size. One cubic centimeter of air contains about 2.5 *10 to the power 19 (25,000,000,000,000,000,000) molecules.
Even though a tiny piece of matter contains a very large number of molecules, yet there are empty spaces in between them. Molecules of matter are constantly in random motion. As the temperature increases, the motion of the molecules also increases. the hotter the substance, the faster is the motion of the molecules. Molecules of a gas move very fast in comparison to the molecules of liquids and solids. Even the molecules of ice are in motion. Now the question arises: when molecules of all the substances are in motion, why don't substances appear shaky? The reason is: there exists a force of attraction between the molecules which keeps them together. If this force is not present, the molecules of matter will scatter away in all directions.
When heat is given to the molecules of a solid, the speed of the molecules increases and the force of attraction decreases. If we continue adding heat, the speed of the molecules would be still faster and the solid will change into liquid and finally to gaseous state.