Gas rarr liquid And thus steam water vapour condenses to liquid water. This causes the water vapor to change state and become tiny drops of liquid water. Changing States Of Matter For Kids Dk Find Out Energy is transferred from the water vapor to the cup which cools the water vapor. . A gas can be converted into a liquid by decreasing the pressure of a gas sample. Intermolecular forces are strongest in the solid state and weakest in the gaseous state for any given material. See full answer below. What factors cause changes between the liquid and gas state. If you heat a liquid strongly enough eventually the particles will be moving around with enough energy that they overcome the forces holding them together in the liquid. A gas can be converted into a liquid by increasing the pressure of a gas sample a gas can be converted into a liquid by cooling a liquid can be converted to a gas by heating. Condensatio...