The Heat is ON
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
Cu ball & wire in burner
Light My Balloon
Transfer by Convection
Archimedes Principle: The warm, low density air is buoyed
up by the cold, denser air.
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:
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