Have the students make a book or poster about sources of light to record their thinking. In a vacuum, where there is nothing to slow it down, light travels 186,282 miles per second! Sources of light hot objects give out light. The speed of light light moves at the fastest known speed in the universe. The sun, the moon, the stars, flashlights, light bulbs, fire, fireflies, rainbows, matches, fireworks, lamps, and lasers.