Conduction, Convection, and Radiation

Convection Cell (Thymol Blue Cell)

What it shows:

Here we set up a convection cycle, where we heat part of a fluid; it expands, rises, then cools and sinks. A two dimensional model for real convection cycles in the atmosphere, oceans or stellar interiors.

How it works:

The convection cell is made from two sheets of 0.5cm plexiglass (front clear, rear translucent), separated by a 0.5cm gap for the liquid, the indicator thymol blue. The sides are plexi and the top left open, but the bottom is sealed with a hollowed brass rod. The brass serves two purposes. Firstly...

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Convection Cell

What it shows:

Hot fluid rises, cool fluid sinks. Here is a desktop convection cell modeling the processes in the atmosphere, oceans or stellar interiors.

How it works:

The currents are set up in rheoscopic fluid 1 (basically minute aluminum flakes in water) in a small 10×10×15cm glass tank. Half the base of the tank rests on a heater, the other on an aluminum block that acts as a heat sink. The rheoscopic fluid has a weird metallic sheen such that the bulk motion of fluid is clearly seen from the changing reflectivity....

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Black Body Radiation Oven

What it Shows

Black body radiators in thermal equilibrium should emit the same spectrum of radiation; inside a muffle furnace at high temperature, objects should appear the same color, whatever their material.

How it Works

Place a piece of brick and an iron ball into a kiln (ours is a Blue M Electric Co. kiln with 25cm × 12cm × 10cm oven) that has a temperature range up to around 1000°C. Close the door and crank up the temperature to maximum. Depending on the type of kiln, it will take around 20 minutes to reach equilibrium (a good length of time for a...

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Detection of IR radiation from hair dryer and/or special IR source.

What it Shows:

Detection of infra-red radiation by the rotation of a paddle-wheel vane inside a low pressure flask.

How it Works:

A radiometer consists of a partially evacuated flask containing a four bladed vane (see figure 1). One side of each blade is a matt black, the other silver. The black surface, being a better absorber and radiator of heat, warms the air above its surface more than the silver. The resulting higher kinetic energy of these air...

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