solid carbon dioxide
Solid carbon dioxide is also called dry ice. Thats because when it gets warmer and changes state, it doesnt change to a liquid by melting. Instead, it changes directly to a gas without going through the liquid state. The process in which a solid changes directly to a gas is called sublimation . It occurs when energy is added to a solid such as dry ice. You can watch dry ice changing directly to a gas in the video at this URL: http://www. youtube. com/watch?v=J8mDGwf-5x0 .