ペーパーブーメラン／Paper Boomerangs

DENJIRO: This is another episode of "The Summer Vacation Science Project Special." Here’s today’s subject. A boomerang made of paper. It's easy to make, and it's a great science project. NARRATOR: Let's first see how it's made. We'll cut out three strips of cardboard. Stack them together and make a small cut in each of them. Join the three pieces together at the cuts. To secure them together, staple the center of the boomerang. DENJIRO: That's all there is to it. But it's still too early to call this a boomerang. We need to twist it so that the right side of the wing is slightly bent upward. But very slightly. Do this for all three wings. And slightly curve the wings at the center. Just a bit, though. This will make the boomerang return to you. Now, I'll show you how to throw it. The side were the wing are bent upward is the topside. That’s the green side for this. The topside should be facing your face. Hold the blade between your fingers. Use your wrist to give it rotation as you release it. Watch. It comes back to you. Here are the important points in doing a science project on paper boomerangs. We bent the right side of the wings upward earlier, but we could bend the left side of the wings upward now. Do that for all three wings. Let's throw the boomerang. BOY: It's rotating in the other direction! DENJIRO: As you can see, by changing which side of the wing is bent upward, we can change the direction of rotation. NARRATOR: Paper boomerangs change how it flies depending on how much you twist and bend the wings. Try experimenting. DENJIRO: I hope energy will bring you all happiness. Our magic word is "Happy Energy!"