"Simple text and full-color photos instruct readers how to make a mystery smell balloon and explain the science behind the activity"-- Pebble Plus: Hands-On Science Fun series. RL: K-1; IL: PreK-2 Interest Level: K-3 Reading Level: 3.2 Lexile Measure: 420 Lexile Code: IG (Illustrated Guide) Guided Reading Level: L Fountas & Pinnell: M.