SciGirls has a passion for pixels. When you look at a photo of a planet in space, did you know that you're really looking at a set of numbers? Remote-sensing satellites take pictures and gather data that is transmitted to the ground as digital signals, or sets of numbers. Then computer software converts the numbers into color images.Have your students play with data transmission using this SciGirls activity as you guide them through encoding messages into digital signals they send each other. The only materials they’ll need are pencils and grid paper!