Thermal Expansion
Thermal Expansion
Thermal Expansion
higher temp
low temp
Objectives
higher velocity
slower velocity
requires more space
requires less space
Explain why thermal
expansion occurs & give
examples.
Calculate an objects
thermal expansion or
contraction of new length.
Explain differences in
expansion of water.
Thermal Expansion of Water
As the temp. decreases from 4°C to 0°C,
water expands - ice.
Calculating Thermal Expansion Different materials expand at different amounts with the
same temperature rise.
Solids (length)
The maximum density of water
(1.0 g/mL) occurs at 4°C.
Linear Expansion Coefficients (°C ­1)
∆L = LO x α x ∆T
Thermal Expansion Problem
Aluminum
Brass
Copper
Glass
Gold
Iron (Soft)
Lead
Quartz
Steel
23 x 10­6
19 x 10­6
16 x 10­6
3.2 x 10­6
14 x 10­6
12 x 10­6
29 x 10­6
.40 x 10­6
11 x 10­6
L = ?
T1 = 20 oC
Lo = 20.0 c
m
T2 = 600 oC
1
Thermal Expansion
Thermal Expansion Problem
Thermal Expansion Joints
The Eiffel Tower, constructed in 1889 by Alexandre Eiffel,
is an impressive latticework structure made of steel. If the
tower is 301 m high on a 22 oC day, how much does its
height decrease when the temperature cools to 0.0 oC?
Bimetallic Strip
(Heat)
Thermostat
Steel
α = 11 x 10­6 oC­1
Bimetallic Strip
Brass
α = 19 x 10­6 oC­1
Steel
α = 11 x 10­6 oC­1
Brass
α = 19 x 10­6 oC­1
(Cool)
Assignments . . .
­ Begin Chapter 21 Homework #16 ­ 20 2