Demonstrates the linear expansion of solids and allows comparison of expansion rods of different materials. Comprises cast metal end supports mounted at each end of a horizontal metal reservoir, open at the top, that can take any liquid fuel such as alcohol. One of the end supports has a scale with pointer needle on the outside to indicate the expansion in the rod. Expansion rods supported in the holes near top of both the end supports and can be clamped at the end opposite to that of scale pointer. Burning of fuel in the reservoir causes rod at the top to expand, which in turn pushes the pointer needle showing deflection in the scale. Includes three expansion rods, 1 each of brass, copper and aluminium.