Fun Earth Day Activity. 21 vocabulary words are included in this crossword puzzle for Earth Day. Students will enjoy this fun vocabulary activity. Includes the words conserve, reduce, reuse, recycle, Earth, ecology, environment, ozone, pollution, growth, and more. Good activity for Earth Day, spring, or for a filler before and after state testing. Good supplement to a unit on environmental science. Earth Day Every Day. Digital and Print: Includes an Easel Activity ready for learning with digital