What crafts can straws be used for?

We all know that straws can be used to suck drinks, but besides sucking drinks, straws can also help us understand many scientific principles.

Straw whistle

Methods:

Whistle 1: Cut a small piece of straw, block one end with your hand, blow to the other end, adjust the angle, you will find that, at a certain angle, the straw becomes a whistle, and you can blow out the sound, the sound of the sound is thick.

Whistle 2: Cut a small piece of straw, use a sharp knife to cut the end of the straw into a trapezoid, and then blow directly into the trapezoidal end of the blowing, such as Figure 1. It also makes a sound, but a very sharp one.

Scientific Principle:Sound is made by the vibration of objects. The first whistle and the second whistle make different sounds because the vibrating material is different. The first whistle makes sound because of the vibration of the air, while the second whistle is made by two trapezoidal flakes vibrating against each other.

Straw weathervane

Making method: Cut a 20mm-long opening at one end of a long straw and insert a piece of cardboard, insert a big pin vertically in the middle of the straw, and then fit it into the end of a short straw, as shown in Figure II. In this way, a simple straw weathervane is ready.

Scientific principle: When the wind blows, the airflow will drive the straw weathervane to rotate, so that we can determine the direction of the wind. Of course, a real weathervane tail is much more complicated than this one, in order to tell when the wind is coming from different directions.

The straw vane

How to make it: At one end of a long straw, cut two 2Omm long slits 90 degrees apart. Take a piece of 50 x 50mm paper, fold it into a triangular tail as shown in Figure 3, insert it vertically into the cross notch of the straw, and fix it with transparent tape. Wrap transparent tape around the other end of the straw to adjust the center of gravity of the fly marker, as in Figure IV.

Scientific Principle: According to the principle of air fluid, the triangular wing at the tail can make the flying mark fly more smoothly.