Ethanol and water are mixed in volumetric glassware, showing a volume decrease and a temperature increase.

Two 250 ml graduated cylinders are filled to the line with water and ethanol (100%). A temperature probe shows both at room temperature. The temperature probe is then moved to an empty 500 ml graduated cylinder, and the contents of the two smaller cylinders poured simultaneously to mix well. 

The temperature of the mixture rises about 8°C, and the volume decreases to 480 ml just after mixing, clearly visible on the scale of the 500 ml cylinder, and to the class by camera. The temperature is visible on the screen of the demo computer turned toward the class, running LoggerPro, with the digital thermometer readout expanded to full screen.