Today’s Wonder of the Day was inspired by Sahasra. Sahasra Wonders, “Do you love jet skiing?” Thanks for WONDERing with us, Sahasra!
Others enjoy feeling the wind in their hair as they speed along the surface of the water. Have you ever ridden in a speed boat? It can be a thrilling experience to bump along the tops of the waves and feel the spray of the water.
But what about an even more personal experience riding the waves? What if you could ride a bike or a motorcycle on the water? Wouldn’t that be cool? Well, you can come close to that sensation, if you want. All you need is a personal watercraft!
You may know these exciting water machines by one of their most popular brand names: Jet Ski®. Personal watercraft (PWC) can be found on lakes, rivers and oceans all over the world. Since the late 1960s, these small, fast, personal boats have become extremely popular.
Most regular boats boast large motors that rapidly spin a propeller to move the boat. Personal watercraft, on the other hand, contain engines that are similar to jet engines in planes. Instead of turning a propeller, they push the craft forward by squirting a powerful jet of water behind the craft.
How does that work? Is it magic? No! It’s science, pure and simple. Specifically, it’s Isaac Newton’s third law of motion at work. You may have heard Newton’s third law of motion stated something like this: “Every action has an equal but opposite reaction.”
That might sound confusing at first. But it’s easy to understand if you think of a practical example. If you want to move forward on a skateboard, which direction do you push? Forward? No! You push backward. That action (pushing backward) has an equal but opposite reaction (you move forward).
Personal water craft work on the same principle. The engine powers a pump, called an impeller, which sucks in water and blasts it out of a hole in the back of the vehicle. The force of the water pushing backward drives the craft forward.
Personal watercraft—and their passengers—weigh more than the water being pushed out the back of the craft. That means they need powerful engines. They have to push the water out fast enough to move the craft forward quickly. That’s why many personal watercraft have engines that are as large as those you might find in a small car or large motorcycle!
Although Newton’s third law of motion is hundreds of years old, modern personal watercraft weren’t invented until the late 1960s. Clayton J. Jacobson is usually given credit for its invention. However, many of the important pieces of modern personal water craft, including the impeller and fiberglass body, were already in existence.
Have you ever ridden a PWC? Would you like to? When used safely, they can offer a fun day on the water! What other activities do you enjoy on warm summer days?
Standards: NGSS.PS2.A, NGSS.PS2.B, CCRA.L.3, CCRA.L.6, CCRA.R.1, CCRA.R.2, CCRA.R.4, CCRA.R.10, CCRA.SL.1, CCRA.SL.2, CCRA.W.2, CCRA.W.9, CCRA.L.1, CCRA.L.2