An inverted 100 ml beaker is placed inside a 400 ml beaker filled with colored water. The 400 ml beaker is placed on a hot plate. The water boils for a while, and then the beaker is removed. The water vapor inside cools condenses back into liquid. The molecules of a liquid take up less space than a gas, and therefore the pressure inside lowers. The atmospheric pressure pushes the colored water up inside the beaker. This demonstration can be found in Tik L. Liem’s Invitations to Science Inquiry.