Styrofoam is actually 98 percent trapped gas

When you hold a block of Styrofoam, you are mostly holding breath. This material is created by expanding tiny plastic beads to fifty times their original size using heat and gas, resulting in a matrix where the actual solid matter accounts for only two percent of the volume. The rest is a labyrinth of microscopic gas pockets, each averaging just 0.2 millimeters wide. These tiny bubbles are so effective at blocking heat that the foam insulates fifteen times better than solid concrete.