Gallium as a simple substance in its pure form is a brittle
silvery-white metal. Its most important feature is that gallium melts at
a temperature of 29.76 ° C, so it can be melted in warm water, on a
battery and even in your hand!
Although gallium is only third in the world of metals in terms of fusibility, it is the only metal that can be safely held liquid in the palm of your hand: mercury (first place, mp -38.83 ° C) is very toxic, cesium (second place, melting point 28.6 ° C) is so reactive that it ignites in air.
Another interesting physical property of gallium is the boiling point of 2204 ° C, which means that gallium is in liquid form over a very wide range of temperatures, thus finding use in high-temperature thermometers. At the same time, gallium practically does not evaporate at room temperature (and at 100 degrees too): it is 4.520.000.000.000.000.000.000.000.000.000 times less volatile than water and 390.000.000.000.000.000.000.000.000 times less volatile than mercury (calculated based on vapor pressure at 30 ° C)
The low melting point, relatively low chemical activity and very low volatility of gallium on the one hand and the external similarity with other metals on the other hand make it possible to use gallium for tricks. In addition to the aforementioned ability of the metal to melt in the hand, its almost instantaneous melting in hot water can also be used very effectively: a teaspoon is made from gallium and allowed to stir hot tea with it. As you might guess, the spoon melts and flows down to the bottom of the glass