The document discusses thermal expansion in solids. It explains that solids expand when heated as the internal energy of atoms increases, causing them to vibrate and occupy more space. This is why gaps are left between railway tracks - to allow for expansion on hot days which could otherwise cause bending and accidents. Equations of linear, area, and volume expansion are provided, stating the change is proportional to the initial measurement and temperature change.
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Expansion solid
1. Apperception Why is a space left between the railway line where one piece joins the next?
3. Activity Using your Student Worksheet 11.6 (page 129) Do the experiment in your group
4. Summary Solid expand when they are heated, and decrease in volume when they get colder. From a microscopic point of view, the result of heating a material can be explained as follows: There is an addition of energy to the material The internal energy of the atoms of the material increase, causing atoms to vibrate The vibrating atoms now occupy more space when hot compared to when cold.
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6. Thermal Expansion Expansion of solid Expansion of liquid Expansion of gas Linear expansion Area expansion Volume expansion l= lo. . t A= Ao. . t V= Vo. . t
8. Linear Expansion The magnitude of the thermal expansion of the solid depend on : Type of solid Temperature rise Length
9. Linear Expansion The expansion of solid body is proportional to the temperature rise and to its length We can make Formula l l o t
10. Summary Or We can write in equation of thermal expansion: l = l o t l = change in length (m) = coefficient of thermal expansion ( o C 1 ) l o = Initial length (m) t = change in temperature ( o C)
11. Summary On a hot day, the metal expands and if it were not allowed to do this, the rails would bend out of shape. This has caused railway accident in the past. click
14. Summary Or We can write in equation of thermal expansion: A = A o t A = change in Area (m 2 ) = coefficient of thermal expansion ( o C 1 ) A o = Initial Area (m 2 ) t = change in temperature ( o C) click
17. Summary Or We can write in equation of thermal expansion: V = V o t V = change in Volume (m 3 ) = coefficient of thermal expansion ( o C 1 ) V o = Initial Volume (m 3 ) t = change in temperature ( o C)