Can you float twenty pennies in a boat made of these materials? That was the question posed at this weekend’s Engineering Challenge. The children were given tin foil, wax paper, coffee filters, saran wrap, soda straws, popsicle sticks, and masking tape to build with.
Before the program started we talked about what makes a boat float, and why boats can float even though they are heavier water. If I were to run the program again, I think I would also have spent five minutes talking in more depth about the materials we were going to use and their properties.
As usual, I created several level of challenges. I was reasonably sure that everyone would be able to float 20 pennies by the end of the hour (though it took some children quite a long time to achieve that goal) and that others would succeed on their very first attempt. Multiple challenges meant that everyone could ultimately be successful with at least one goal, while also being given levels of challenge that were truly difficult for that individual to achieve. Once a child
managed to float the pennies, they almost always immediately ran to get more pennies to see just how many they could float in that particular boat before it sank, so “float more pennies” was not going to be much of a challenge. Instead, I noticed that since tin foil featured very heavily in most of the initial designs, I made the second level of challenge be to float twenty pennies, but without using tin foil. Since tin foil folds so easily and maintains its shape in a way that the other materials do not, this meant that most of the children had to completely revise their designs, rather than just recreating them in a non-tin foil material. The third level of challenge was to float the pennies using only two materials.
There was a lot of trial and error with this challenge. I did not need to emphasize that the engineering process involves a lot of redesigning to make improvements because the children were highly engaged in tweaking their designs. I did not see any frustration during the program. Even the child who struggled with the first level of challenge was motivated and happy as he tried design after design until he finally found one that worked. Luckily his mother understood how important it is for children to work through their own ideas, and let him experiment with designs that, from an adult perspective, were clearly not going to be successful. She did confess afterwards that it was quite difficult not to jump in and just tell him the “right” way to do it. It was all worth it to see the growth in understanding as the program progressed, not just in how boats are designed, but also in how the various materials interacted with one another and with the water. (This is why I should have had a discussion about the materials before we began building.)