Thermal Expansion ProblemT = 20 C L = 20.0 cm T = 600 C · Linear Expansion Coefficients (°C 1) L = 20.0 cm o T = 600 2 o C Thermal Expansion Problem T = 20 1 o C. Thermal Expansion

Thermal Expansion

1

Thermal Expansion

Explain why thermal expansion occurs & give examples.

Objectives

Calculate an objects thermal expansion or contraction of new length.

Explain differences in expansion of water.

Thermal Expansion

higher temp higher velocity requires more space

low temp slower velocity requires less space

Thermal Expansion of Water

As the temp. decreases from 4°C to 0°C, water expands - ice.

The maximum density of water (1.0 g/mL) occurs at 4°C.

Different materials expand at different amounts with the same temperature rise.

Solids (length)

Calculating Thermal Expansion 

∆L = LO x α x ∆T

     Aluminum 23 x 10­6

    Brass      19 x 10­6

    Copper      16 x 10­6

    Glass      3.2 x 10­6

    Gold      14 x 10­6

    Iron (Soft) 12 x 10­6

    Lead      29 x 10­6

    Quartz     .40 x 10­6

    Steel      11 x 10­6

   Linear Expansion Coefficients (°C ­1)   

Lo = 20.0 cm

T2 = 600 oC

T1 = 20 oCL = ?

Thermal Expansion Problem

Thermal Expansion

2

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?

Thermal Expansion Problem Thermal Expansion Joints

(Heat)

Bimetallic Stripα = 11 x 10­6 oC­1

Steel

Brassα = 19 x 10­6 oC­1

Bimetallic Stripα = 11 x 10­6 oC­1

Steel

Brassα = 19 x 10­6 oC­1

(Cool)

Thermostat Assignments . . .

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