Chapter 10

The Heat is ON

Part 1

Demos to Prepare:

Heat & Transfer:  
Feel warm & cold at same temp
Boil water in paper cup
KMnO4 in liter beaker
Chapel Royal wind blast
Smoked Can Radiator
Crookes Radiometer
Greenhouse Effect
Thermos Bottle
Cu ball & wire in burner
Light My Balloon
Ocean Currents
"Twinkling Stars”
Plate Tectonics

Transfer by Convection

Archimedes’ Principle: The warm, low density air is buoyed
up by the cold, denser air.

Bimetallic Strips

Thermostat and Compensated Balance Wheel

The two metals in the bi-metallic strip expand different amounts with
heating. Hence the strip bends with temperature changes.
The bending operates the electrical contacts for thermostats, and keeps
the clock wheel in balance for constant speed at differing temperatures.

Demos on Expansion:

Steam Expansion Device
Red hot glass, quartz & water
Cracked engine block.
Hole in plate when heated gets bigger.
Ball in Ring:
Railroad wheels
The Brass Monkey
Electrically heated nichrome wire.
Bridge expansion joints.
Pendula & balance wheels.
The SLV Steam Lines-- No allowance for expansion.
   Big problem!  Boiling mud eruptions, etc.
Vernier  & Temperature  Probes. 3-L beakers.

The Problem: L = 600.0mm, t1 = 20oC, t2 = 100oC, so Δt = 80Co. ΔL = 0.93mm. Substituting and solving for α, we find that α = 19.3 X 10-6 ΔL/Co. From the Table, it's Brass.

Hydrogen balloon explosions! Video:

Here Endeth Heat Part 1

Go to Vapor Pressure and Boiling Point