Paper 1:

The wonderful drawing of the jigsaw puzzle, the solid structure of the bridge load-bearing design, the race against time on the Rubik's cube, although the science and technology festival has passed, I still remember the attempts and competitions again and again!

Our school has carried out three projects in this science and technology festival competition: jigsaw puzzle, bridge load-bearing design and Rubik's cube. I participated in the first two competitions. When I arrived at school in the morning, the playground was already bustling, and everyone was ready to try their hand. The north wind roared and the leaves rustled, but they couldn't extinguish everyone's passion.

In the jigsaw arena, the students took out their drafts and sat on the floor, and the group composed of several other students and I also worked hard to create them. Everyone had a clear division of labor, United as one, and began to color each other.

A small problem suddenly appeared. After several revisions, the color of the city wall was not satisfactory, so Chen Xin and Li Mingpu repaired it again with crayons, but the crayons were too thick and easy to draw a grid. At this time, Li Mingpu came up with the idea of drawing with colored pencils and adding a layer to the outline, so that our city wall was conquered under the triple attack of colored lead, crayons and colored pencils.

Time passed quickly, and soon the game time of Tangram was over, and the students were very satisfied with their works. I am very pleased with this spirit of unity and overcoming difficulties.

The next bridge load-bearing design competition is even more thrilling and unforgettable. This competition is very difficult for our group. First of all, the bridge can be made in advance at home and directly take the finished product to participate in the competition, but we understand that the bridge is made on the spot, so we have no choice but to apply to the referee for our final and make the bridge on the spot first.

In this way, we will spend more time and energy on the construction site to build bridges nervously, and we will cheer for each other. Although it was not as fine as it was made at home, it took us about three minutes to complete the paper bridge, with three layers of corrugated paper folded in the middle and a layer of A4 paper wrapped around it as the bridge deck. At this time, the referee asked for a class every six years, so we took to the stage with tension, excitement and a little confidence.

Of course, the last feeling is the most important, we have the courage and confidence to accept the challenge! At the beginning of the game, we calmly paved the bridge deck and then took out a heavy box and put it on it. Whenever the bridge trembled slightly, our hearts trembled. Reality is better than imagination. When four 3200-gram weight boxes have been placed on the bridge deck, our bridge still stands, which gives us great encouragement!

But when two water bottles were put on, the bridge suddenly lost its balance, and my heart seemed to lose its balance and began to beat violently. Fortunately, I kept the bridge in time. Now we are faced with a difficult choice: whether to continue to take risks and win, or stop when it is good, that's all. After discussion, we are prepared to take risks conservatively.

I began to add water bottles carefully to master the balance in real time, and added two more water bottles with a weight of 2400 grams! Of course, it is also necessary to be conservative. If you are good, you will accept it! In the end, we won 5600 grams of bridge * * * and won the second place in the grade group! I can't believe my eyes. We overcame many difficulties and turned defeat into victory! That little bit of confidence and the third choice-courage and wisdom-made our game successful!

The Science and Technology Festival is over, but tense scenes and competitions often flash before my eyes!

Paper 2:

When you eat a big and sweet peach, have you ever thought about how this peach grows? Why do peach trees always bear fruit after the peach blossoms are in bloom? It seems that the formation of fruit is related to flowers.

I tore off the petals with tweezers and carefully observed the structure of stamens and pistils with a magnifying glass. I found that the main part of stamens is anthers, and there are pollen in the anthers. The main parts of pistil are stigma and ovary, and there are ovules in the ovary.

How is the fruit formed? It turns out that the fruit must be pollinated first, that is, the pollen must reach the stigma. When butterflies, bees and other insects suck nectar between flowers, they pass pollen to the stigma. After pollination, the pistil of pollen germinates on the stigma, and the pollen tube extends downward to the ovule in the ovary. After the sperm in the pollen tube combines with the egg in the ovule, the ovary gradually expands to form a fruit; Ovules in the ovary form seeds.

Will female flowers bear fruit without pollination? I once did an experiment: on a pumpkin vine full of flowers, choose a female flower of a pumpkin that has not yet opened, and cover this flower with a plastic bag. I observe it carefully every morning. After a few days, the covered female flowers slowly died, while other female flowers on the vine were pollinated by the media. After the petals withered, I saw the ovary slowly expanding and gave birth to a small pumpkin.

Experiments show that fruit formation is closely related to flowering and pollination.

Paper 3:

Since the birth of mankind, there has always been a dream, a dream to fly freely like a bird. Humans have a headache about this: why birds can fly into the sky with their wings, but humans can't. After several generations of efforts, the human dream has finally come true!

At first, using the principle of air, mankind made every effort to create the first "bird" that attracted worldwide attention-a hot air balloon. But when the storm came, there was nothing I could do but watch it fall from the sky. Although the hot air balloon has realized people's wishes, it is only a small step for mankind.

Later, the Wright brothers in the United States took the second step in the history of flight with amazing efforts-they made the first plane in history. This feat makes the human dream of flying more perfect.

Since people made the first plane with their own hard work, human beings have improved the plane again and again and achieved good results. But human beings are not satisfied with just flying in the sky, but decided to explore the mysteries of the universe, and human beings are busy for this. ...

In 2000, mankind made great progress. Humans have sent their spaceships into the sky many times to explore mysterious planets, such as Mars and Jupiter. I also got a lot of valuable information, but my motherland, People's Republic of China (PRC), has not yet realized the grand aspiration of manned space flight, although we have made the spacecraft a passenger in space.

Scientists in China are busy realizing this long-cherished wish. Finally, in September 2004, the people of China finally realized this wish. The successful launch and safe return of "Shenzhou 5" bears the hopes of uncle Yang Liwei, a space hero, and the people of the whole country. After the launch of Shenzhou 5, Shenzhou VI also flew into space happily. This also makes China people stand up straight on the road of scientific and technological development!

The launch of Shenzhou VII excited me, an ordinary pupil. I believe that the launch of Shenzhou-8 and Shenzhou-9 will not be far away, and they will also leave a deep imprint on China, which has made brilliant achievements in space history.

History will turn a new page. What kind of strokes should I draw on a blank page? The future belongs to us, and we should try our best to paint a brilliant stroke for it. Perhaps in the near future, the newly built spacecraft will take us to another wonderful world, a new world waiting for us to explore.

Let's fly to the ocean of knowledge with a heart that looks forward to flying like a bird, fight against the blue sky and make contributions to the future of our motherland!