In this playful activity, learners explore the structure of the cell—the basic unit of every living organism—by creating a model of cell structures using soap bubbles, and by examining a slice of onion under a magnifying glass. After blowing bubbles in soapy water, learners examine the shape of the bubbles and how they fit together to help them understand the shape of cells and the function of cell parts such as the cell membrane. Then learners attempt to identify cellular structures in onion slices. (They can try doing the same in other vegetables too, like celery or romaine lettuce.) This activity can be found on pages 18-19 of the activity guide.