Sam: Welcome to the Sound of Science on WNIJ. I’m Sam from NIU STEM Outreach.
Christine: And I’m Christine from NIU Outdoor Adventures, and this weekend I’m going kayaking.
Sam: If you’ve never been in a kayak, it’s like most other boats - except really narrow. And light weight. And you’re almost sitting below the water level.
Christine: In fact, all three of those things are important for kayakers. Most small watercraft tip over easily because the center of mass is higher than the water. That’s why you shouldn’t stand up in a canoe or rowboat. Now, if a kayaker ever flips over or is upside down in the water, they can easily slip out. But manually flipping a kayak, getting back in, and pumping the water out takes time.
Sam: It sounds like you’re saying there’s another way to do it.
Christine: There is! It’s called a kayak roll. You stay in your seat while wearing a sprayskirt which keeps water from entering while using fluid dynamics to get you back upright. You put your paddle parallel with the water’s surface, then twist your paddle and hips at the same time. If you do it fast enough and hard enough, you’ll roll over like nothing ever happened.
Sam: You mentioned speed and strength are key to the roll. Why is that?
Christine: Think about swimming. If you paddle really slowly, you might not go anywhere. If you need to move, you pull your arm hard enough to get you to move. It’s like dragging yourself through the water. Compared to air, water is really thick. It can’t normally be compressed, it can only be moved apart. When you paddle, you’re racing against the water. The harder you paddle, the less time the water has to move away from itself.
Sam: So with the kayak roll, it’s as if the water is more like molasses if you’re fast enough?
Christine: Yeah, but only around the paddle itself, not around the kayaker.
Sam: You can learn more about kayaking from Christine and her Outdoor Adventures staff! This has been The Sound of Science on WNIJ.
Christine: Where you learn something new everyday.