In this quick activity (page 1 of the PDF), learners will test how many pennies a flat paper index card bridging the gap between two stacks of books is able to support. Then, learners alter the structure of the same card by folding it accordion-style and retest by again stacking pennies on top. Learners look for a relationship between the number of folds and the number of pennies the card can hold by creating a scatter plot. Relates to the linked video, DragonflyTV: Tug O’ War.