Note that no matter what kind, it is best to have a parachute-like device and find a lighter and larger material.
During the experiment, you will find that it falls so fast. I was particularly worried at that time. I was particularly worried, the sixth floor. . . Fortunately, it is not broken. It seems that this device is very light. . .
Personally, I think the stick is too heavy. . . At that time, we all used electronic scales to weigh it, and once we weighed it, it felt particularly heavy. . . . The balloon should be light, and the first one is ok.