The present disclosure concerns embodiments of a thermal switch used to control the transfer of heat from a heat source to a heat sink. According to one aspect, the thermal switch can be activated, or turned “on”, so as to establish a path of low thermal resistance between the heat source and the heat sink to facilitate the transfer of heat therebetween. The thermal switch can also be de-activated, or turned “off”, so as to establish a path of high thermal resistance between the heat source and the heat sink to minimize or totally prevent the transfer of heat between the heat source and heat sink. In certain embodiments, the thermal switch includes at least drop of a thermally conductive liquid that thermally couples the heat source to the heat sink whenever the switch is activated.