Tisch

At noon today, I looked at the map of China at home. My father asked me, "Do you know which railway to take from Beijing to Shanghai?" I replied: take the Beijing-Shanghai line. Dad asked again, do you know how many kilometers there are on the Beijing-Shanghai line? Can it be measured by map?

Looking at the winding lines on the map, I am a little confused. How to measure them? I tried it with a ruler first, but no, the bending place is not easy to calculate; I used the rope again, it was too thick, and it was not allowed. At this time, I saw my mother sewing clothes, so I used cotton thread and I measured it with my father.

First, put the cotton thread along the beijing-shanghai railway line, cut off the redundant part, and measure the length of this cotton thread with a ruler as 15cm. Dad said, what is the scale of the map at this time? I checked that it was 1: 9000000. According to this ratio, I calculated that the length of the Beijing-Shanghai line is 1350km, in order to test whether our measurement is accurate.

I asked my father, why are the two sets of data different? Dad said, "We measured it accurately, and it is normal to have a little error. After all, we measured it on the map with cotton thread. "

extreme

I participated in the "Starlight Cup" technology winter camp organized by jianye district Children's Palace this morning. Our task is to make model planes. In the process of making them, I found many places where we used what we learned in mathematics.

First, use a ruler to carve three parallel lines on the wing, and the lines should be perpendicular to the edge. Then, put it at the right angle of the table and fold it hard so that both ends are inclined at an angle of120 with the horizontal part. This place uses the knowledge of "angle", which I secretly enjoy. The teacher told us that grasping the angle can make the plane fly farther.

When making the tail wing, first stick the double-sided tape on one end of it, and then stick it on the horizontal tail wing. Be sure to remember that when the vertical tail is stuck, it should be perpendicular to the horizontal tail, otherwise the plane will not fly high and unstable, and will soon fall down.

The plane will be finished soon. The teacher led us to the school playground for a test flight. During the test, my plane flew 12.04 seconds. The teacher praised me for my good flying. I'm so happy. Through this activity, I learned to make a dynamic model plane. In the process of making, it not only cultivated my practical ability, but also made me find that mathematics is everywhere.