Expansion solid
17
Apperception • Why is a space left between the railway line where one piece joins the next?
Transcript of Expansion solid
Apperception
• Why is a space left between the railway line where one piece joins the next?
Thermal Expansion
Objective
Investigating thermal expansion in solid
Activity
Using your Student Worksheet Using your Student Worksheet 11.611.6
(page 129)(page 129)
Do the experiment in your Do the experiment in your groupgroup
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.
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
Linear Expansion
lo
l
lt
Linear Expansion
• The magnitude of the thermal expansion of the solid depend on :– Type of solid– Temperature rise– Length
Linear Expansion
• The expansion of solid body is proportional to the temperature rise and to its length
We can make Formula
l lo t
Summary
Or We can write in equation of thermal expansion:
l = lo t
l = change in length (m) = coefficient of thermal expansion
(oC1)lo = Initial length (m)
t = change in temperature (oC)
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
Area Expansion
AoA
At
Area Expansion
We can make Formula
A Ao t
Summary
Or We can write in equation of thermal expansion:
A = Ao t
A = change in Area (m2) = coefficient of thermal
expansion (oC1)Ao = Initial Area (m2)
t = change in temperature (oC)
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Volume Expansion
Vo V
Vt
Volume Expansion
We can make Formula
V Vo t
Summary
Or We can write in equation of thermal expansion:
V = Vo t
V = change in Volume (m3)
= coefficient of thermal expansion (oC1)
Vo = Initial Volume (m3)
t = change in temperature (oC)
