This set helps to perform a qualitative comparison of the degree of thermal linear expansion of the three materials: steel, aluminum and brass in the form of rods. This live experiment, thanks to the indicators acting as single-sided levers with large leverage, allows the user to clearly assess the relative thermal expansion of the these metals.
The set consists of a matel base ( approx. 23 cm x 9 cm x 7 cm) with two brackets, three indicators in different colours (length: 19 cm) and plate holders, scale on brackets, three rods for experiments (steel, aluminium, brass, length: 18 cm, dim. 6 mm), convection limiter and a plate for alcohol (diameter 7 cm and height 1 cm).
* Preparation for use
Mounting the scale
After unpacking all the sets elements, the first step is to screw out the screws on the side of the bracket which has the common axis of rotation of the indicators. Later, the indicators should be lifted upright. Afterwards, the scale has be placed next to the bracket so that the holes on both elements meet. As a result, the indicators should be on the background of the scale. Then, screw the scale (inscription towards the indicators) to the bracket using the previously removed screws. The indicators should rest on the pin protruding from the scale plate.
* Mounting the rods
The rods should be assembled in a way that will allow the end with the slot to rest on the axis of indicators rotation, catching one of them in the slot; then, the other end with the slot should be secured with one of the three screws on the other side of the base. Having installed the rods, the adjusting screws have to be tighten or unscrewed so that all the indicators show zero on the scale.
* Lauching the show
Plate for the alcohol should be placed in specially prepared handlers underneath the rods. The enclosed rectangular bowl, acting as sectional limitation of convection, can be placed on the rods, exactly above the plate ((upside down, the cuts in the side walls should encompass the rods). Then, it is time to fill the plate with alcohol (e.g. denatured alcohol) and to light it up. After approx. 2 minutes, the indicator of the length of the aluminum rod reaches approx. 10 degrees.