Ants, I believe everyone is familiar with them. Then who can really understand ants? Why don't ants get lost?

With this question, I consulted some books. According to the book, ants leave some smells along the way after starting from the nest to their destination, and then return to the nest. Touch each other with tentacles and notify other ants. Scientists have done an experiment on this problem. Scientists first identify an ant and vigorously clean up the place where he reaches his destination along the way. When the ant came back, it suddenly stopped at the place where the smell was wiped off. Looking for something while walking in circles. People come to the conclusion that ants can tell their directions by their sense of smell.

In order to confirm this conclusion, I did an experiment. I first prepared a twig about 10 cm, and put the bait-small candy on one end of the twig. I put this device near an ant nest. After a while, an ant came out to explore the road. After I led him to the stick, he went to the place where the sugar was put, as if he were smelling it. I took this opportunity to cut off the broken part of the stick by one centimeter. When the ant came back, it turned left and right where it was cut off, but it couldn't find its way home.

After a while, I repeated the above experiment, and the ants still didn't find their way home.

Through these two experiments, I finally know the secret of ants not getting lost. It turns out that ants can tell the direction by smell.

Knowing the secret of ants, I was thinking: Can you make an ant alarm? When an ant approaches the alarm, the alarm can "smell" the ant and then chirp to let us know that the ant has gone to the cupboard or other places.

Sun Si (3)

Instructor: Wu Zhou

Why is the trunk round?

In the process of observing nature, I happened to find that the shape of the trunk is almost round-an empty cone. Why is the trunk conical? What are the benefits of a conical trunk? In order to discuss these problems, I made more in-depth observation and analysis.

With the help of my tutor, I consulted relevant materials and learned that the stems of plants have the functions of supporting plants and transporting water and other nutrients. The stems of trees are mainly composed of vascular bundles. The supporting function of stem is mainly borne by wood fibers in xylem. Although the stems of woody plants will become thicker year by year, in a certain time range, the number of woody fibers in the stems is certain, that is, the cross-sectional area of the stems is certain. Then, based on the assumption that the cross section of the trunk grows into different shapes, we design experiments to explore the reasons and advantages of conical trunk.

Through experiments, we find that when the cross-sectional area and length of (1) are fixed, the vertical supporting force of triangular columnar objects is the largest and the lateral bearing capacity is the smallest; The vertical supporting force of cylindrical objects is not as good as that of triangular cylindrical objects, but the lateral bearing force is the largest; (2) For trunks with the same mass and different shapes, the short conical trunk bears the largest wind force; (3) Wind is a natural phenomenon, which affects the cross-sectional shape and height of trees. The approximate cone-shaped trunk has a low center of gravity, and the huge root system is connected with the earth, so the center of gravity drops lower and the stability is greater; (4) The cross section of the trunk is round, which can reduce the damage, has stronger mechanical strength and can resist the wind attack. At the same time, under the action of the wind, the bending degree of the trunk is similar everywhere. No matter which direction the wind blows, the resistance of the trunk is similar, and the trunk is not easy to be damaged.

The above experiments reflect the laws of nature, and nature enlightens us: (1) A columnar object with a triangular cross section has the greatest vertical supporting force, and its shape can be used in buildings, such as angle steel; (2) A circular object with a circular cross section has the largest lateral bearing capacity, and similar building materials can be found everywhere, such as TV towers and telephone poles.

In the process of observation, experiment and analysis, I gradually explained and revealed the mystery of conical trunk, increased my knowledge, and combined my knowledge with practice, which not only consolidated my knowledge, but also improved my interest in learning, and initially learned the scientific observation and analysis methods.

Six (5)

Instructor: Li Changlu