EXPANSION

When you enter the hot water into the glass, suddenly the glass will be crack. What do you think about that? Any relation with some physics phenomena?

This phenomenon is one of the physics phenomena that called expansion. The glass can be crack because the content in glass expand early than expansion in the outside of glass. Expansion of an object will be happen if the object heat by a heater. In heat process, particles run with the others, so the object will expansion. When the object will be cold, the particles will close with the other, so the object will be shrinking. Expansion can happen in solid, liquid or gasses.

Solid Expansion

If something have heat, the things will expand in all of direction. The size of length, area and volume will increase (happening length expand, area expand and volume expand). The length and area of solid are limited, we can only concentrate in length direction. So it called in condition length expands. If solid have not been heat in steam form but in flat form, such as circular flat we can only concentrate in area expand. When they have heated, they will have area larger than before. If solid have been heated not in stem or flat form, but in cubs, ball, or box form, we can only measure the volume of them.

Liquid Expansion

The main characteristic of liquid is following the form of the place where it will be placed. For example if we place the water into the glass, the form of water will follow the form of glass. Because of this characteristic, liquid only have volume expand.      Volume expand of liquid will bigger than volume expand of solid.

When the glass has been heated, the liquid in glass will expand. But the volume expand of liquid bigger than volume expand of glass (solid). Because of it, the liquid height will increase.

Gas Expansion

Like solid and liquid, gas also expand when it is heated by heater. Because gas haven’t form, so gas only expand in volume.

Some Problem that Caused by Expansion

Ø Installing of glass window

The car glass window can crack because park under the sun light directly at 2 hours. Because the temperature of glass will increase, so it will be expand, when expand, the frame will opposite with the glass expand. So, the glass will be crack. It better if the car park under sun light directly, not closed more, give same space for expand.

Ø Connection of railway track of train

Railway track of train expand in hot day. Because of it, between connections of railway track always give one space, in order expansion of railway track not caused the railway track will be curve.

Ø Telephone wire and electric wire

Installed telephone wire or electric wire is slack, in order at in hot temperature the wire will not break off.