Fourth-grade scientific and technical manuscripts

Science is the foundation of all life, just like a key, which opens the way for us. Can I make a technical manuscript? This is the picture and i

Fourth-grade scientific and technical manuscripts

Science is the foundation of all life, just like a key, which opens the way for us. Can I make a technical manuscript? This is the picture and information I brought you. I hope you like them.

Scientific manuscript 1: fish will not be cold. It's getting colder and colder. We all put on thick winter clothes, but we still feel very cold. The lake is frozen, and we can't seem to see the fish swimming. But my mother said that fish still live underwater. Are fish really not afraid of cold? If so, why? With this question, I looked up the information on the Internet and conducted my own experiment.

I first iced a lot of ice cubes in the refrigerator to keep the original temperature of the water. Then prepare three cylinders of water, the first cylinder is normal temperature water, the second cylinder is low temperature water, and the last three cylinders are water close to ice. Then I bought three kinds of fish, three for each kind, 1, 1, 1 as a group, and then put the three groups of fish into the water tank for experiments. In order to keep the water in the same state, but also ensure the fairness of the experimental results, I deliberately added water with the same temperature to the second tank of water every few hours, and added ice cubes to the third tank of water to prevent the water from becoming normal temperature, which led to the failure of the experiment. And record the situation of fish at that time.

? An hour or five later, I came to the water tank to observe and found that the fish in the first tank and the second tank were equally lively and cheerful. The fish in the third tank of water seems to be in a bad state, like frosted eggplant-faded. I will continue to observe and record. Maybe the fish in the third tank just doesn't adapt to the environment and is in a bad state for the time being. Six hours later, I came to the water tank to observe and found that the fish in the first tank and the second tank were equally lively and cheerful. And the fish in the third tank is dying, which seems to be very unsuitable for the surrounding environment. I quickly recorded this change.

The next morning, I couldn't wait to get to the water in the third tank, only to find that all the fish in the third tank had basically died, leaving only one fish close to death. After I recorded this situation, compared with the previous two records, I found that fish didn't seem to adapt to too cold water.

? At noon, the fish with the strongest vitality also died with its belly up. From yesterday morning to noon the next day, all the fish in the third tank had died, so according to the records of several observations, I came to the following conclusion: people are warm-blooded animals, so we should use clothes to keep warm. Fish is a cold-blooded animal, and its body temperature will change with the change of external temperature. Even in winter when there is ice and snow everywhere, fish will not be frozen like people. But if the water temperature is too low, the fish will die. Through this observation, I know the reason why fish don't freeze. I learned more about a skill that fish depend on for survival and felt the infinite mystery of nature.

Science and technology manuscript fourth grade material 2: the secret of color is on holiday! Speaking of holidays, I have a rare smile on my face. Today, my parents, grandparents went out on business, leaving me alone at home. I feel very relaxed. I lay on the windowsill and watched the clouds floating in the sky. I fiddled with books I don't know how many times, lying in bed and closing my eyes. I haven't stopped since they left anyway. Suddenly, an idea came to my mind: why don't I draw a beautiful picture? I thought about it and took out two pieces of white paper and colored markers. What should I draw? I found a picture with plants and butterflies. I first laid a blank sheet of paper on the picture and described it. Then I took out a red and green marker to draw, but somehow, I got dizzy and even picked up the red marker and painted the butterfly green. When I stared at this painting with amazing eyes for 30 seconds. That's terrible! I painted the wrong color. It should be green plants and red butterflies. I took another look at the picture, then sighed and said, "Let's draw it again!" " "As I spoke, I reached out and took out a second piece of paper to redraw, but when I turned my eyes to this piece of white paper, guess what I saw on this piece of white paper? I see green plants, red butterflies. What's going on here? Am I a ghost? I quickly rubbed my eyes. It's true. What the hell is going on here? Is there something wrong with my eyes or am I hallucinating? I can't figure it out. Hey, I can only wait for my mother to come back and help me solve this mystery!

"Ding" came the door * * * sound. I hurried to open the door. It was my mother who came back. I quickly told my mother what had just happened. My mother first looked at the picture with red plants and green butterflies as I said, and then looked at another blank sheet of paper. Sure enough, my mother also saw green plants and red butterflies on that white paper. Mom said, "Let's ask' 100,000 whys'?" Finally, we found the answer in the book: it turns out that there are three kinds of cells in human retina-one sees red, the other sees green and the other sees blue. All the other colors you see are a mixture of red, green and blue. But if you stare at either color for too long, the cells that look at that color will shut down, and then you will see the remaining colors. Oh, I see! This is why there are confusing color changes on white paper.