The volume of a body is directly connected with interatomic or intermolecular distance of substance. Respectively, increase in volume is caused by increase in these distances at the expense of various factors. One of such factors is heating.
It is required to you
- The textbook in physics, the sheet of paper, a pencil.
Instruction
1. Read in the textbook in physics as the substances having various aggregate state are arranged. It is known that one aggregate state of substance differs from another in obvious external distinctions, for example, such as hardness, fluidity, weight or volume. If to look in each of types of substances, it is possible to notice that the difference is expressed in interatomic or intermolecular distances.
2. Pay attention that the mass of a certain volume of gas is always less than the weight of the same volume of liquid, and that, in turn, is always lower than the mass of a solid body. It means that the quantity of the particles of substance which are finding room on single volume at gases much less, than at liquids, and are even less, than at solid bodies. Otherwise, one may say, that concentration of particles of more solid substances is always more, than at less firm, in particular, at liquid or gaseous. Means, solid bodies have more dense packing of atoms in the structure that means smaller distance between particles, than, say, at liquids or gases.
3. Remember what happens to metals when they are heated. They melt and gain property of fluidity. That is metals become liquids. If to make an experiment, then it is possible to notice that at fusion the volume of metal substance increases. Remember also what happens to water when heating and the subsequent boiling. Water evaporates, representing gaseous state of water. It is known that the volume of steam is much higher than the volume of initial liquid. Thus, when heating bodies the interatomic or intermolecular distance increases that is confirmed by experiments.
4. Define a concept of temperature in the context of the intramolecular structure of substance. It is known that body temperature only characterizes the size of average kinetic energy of motion of the molecules or atoms. Thus, than temperature is higher, especially body particles are mobile.
5. Draw on the sheet of paper a crystal lattice of some any body in the form of nine points representing atoms. Imagine that these atoms fluctuate around the equilibrium situation. Fluctuations of atoms also lead to formation of certain interatomic distances. The size of these intervals is defined by amplitude of fluctuations of atoms. Thus, the body temperature, the more amplitude of these fluctuations are higher that leads to increase in intervals between molecules or atoms of substance and increase, respectively, macroscopic volume.