4.) At room temperature, it changes directly from a solid to a gas a process called sublimation. This expansion causes a rapid temperature drop, and some of the carbon dioxide freezes into solid pellets of dry ice.
5.) Balsa wood combines the two elements necessary to a successful flight: strength and lightness. Balsa wood is also easy to cut and carve with just a good, sharp hobby knife or razor saw, so no need for heavy power tools. Or any lighter wood.
