The fourth grade observation composition is 300 words.
Fourth grade observation composition 300 words 1 Listen to grandpa, ordinary eggs don't float in the water. I want to do an experiment by myself to observe the conditions under which eggs can float.
I first put the raw eggs in containers with cold water and hot water respectively, but the eggs sank to the bottom; So, if you experiment with boiled eggs, will it float? I put the boiled eggs in cold water and hot water respectively, but the eggs still sank to the bottom. I failed the experiment twice, and I felt very uncomfortable. I ran to consult my father. Father said: Only by changing the density of water can eggs float!
Add the right amount of salt to the water and the eggs will float!
I put 20 grams of salt according to the method my father taught me, but the egg still didn't float. I added 20 grams, but it didn't float. Then I added 10 g, and the eggs floated slowly!
I am happy to tell my father: I succeeded! In this experiment, I learned a truth: only by adding a proper amount of salt to the water can the eggs float.
A few days ago, the teacher gave us an assignment-observing animals and plants.
After school, I went home immediately and took out some mung beans. It is not difficult to give mung beans a "home" first. I took out a glass cup because it was easy to observe. Then, I put mung beans in, then I decided to use paper towels as "soil" and "quilt", and finally put some water at home.
These are all good, and then there is only observation. After two hours, the beans look no different. I almost gave up, so I had to say to myself, "Wait a little longer." Five hours later, when I went to observe again, the beans miraculously became bigger. It's amazing to become a giant from a small person! Moreover, these "giants" took off their green coats and revealed "white and tender" meat.
One day later, after school, I ran home at once. I saw beans, and they changed again. Mung beans grow snow-white roots again, as if waving to me!
Bean sprouts grow quickly and beautifully. From beans to bean sprouts. The beans are undressed first, then the roots grow, then the watercress becomes the first leaf, and finally the real leaves grow. After being beaten by wind and rain, it grows stronger and stronger, forming bean sprouts.
Now I understand that the original food on the table-bean sprouts is like this.
In our colorful world, there are still many things worth practicing! Let's take action and observe the little things around us carefully.
Walking, I suddenly saw a black thing. When I saw it, it turned out to be a spider with a big belly and a thin waist. It's weaving a web!
What a big spider! It is about the size of a dollar coin, its skin is dark brown, and its eight opposite claws hold a round belly. It hung in mid-air and I almost cried out in surprise. Can spiders fly? When I looked closer, I saw it hanging in the air by a long and thin thread. The top of the thread is tied to a branch, and the bottom of the thread is connected with a small hole in the spider's stomach. As the eight paws kept paddling, the line was constantly stretched.
Go all the way, see all the way. Hey! Why are there more and more butterflies here? There used to be a stream called Butterfly Ditch not far away. There are many butterflies drinking and playing in the stream. I am very excited, pulling my mother to dance in the sun like a group of people, and I am intoxicated with this picturesque scenery.
Walking, I saw some dragonflies. Although the wings of dragonflies are not big, they hold up the body of dragonflies like kites. Their eyes are big, like a "pocket" glass ball, which is a bit strange but smart. . . . . . When I looked carefully, a drop of rain fell from the eaves and hit its wings heavily. The dragonfly fell, and just as it was about to pick it up, it flapped its wings again and "stumbled" into the sky. . . . . .
The world of insects is really colorful!
Ladybugs have many feet, but they are too fat to climb very slowly. I saw it crawling for a long time, only a few centimeters away. Ladybugs are slow, but cute.
I couldn't help touching it with a twig. I thought it would run away, but I didn't expect it to be motionless on the ground. I thought I was accidentally stabbed to death with a branch, just when I was sad. I saw it crawling slowly again.
That bug is very small and chubby, much smaller than ordinary beetles. Its chestnut back is dotted with seven dark black spots, which looks like a girl's fashion. It is very beautiful.
I finished it in the community fitness square today. When you are tired, rest on the lawn next to you. Inadvertently, I found a ladybug.
I've only seen pictures of ladybugs in books, but it's useless to see China in reality. The ladybug caught my interest, and I immediately walked over and hid beside it to observe.
It turned out that he was playing naughty with me-playing dead. Finally, it climbed into the haystack and disappeared.
The ladybug observed this time is really interesting.
I brought a bowl of rice downstairs to eat today. Spit bones on the ground when eating. I was about to leave when I finished eating. I stopped to observe the ants on the ground.
First, a little ant saw the food and tried his best to move it, but the food did not move.
I sigh for this little ant. Then it returned to its nest and gathered many small ants. They were together, and Qi Xin worked together to carry the heavy food for them. "Sex, sex." Oh! They finally moved the food away. However, I just don't know how they did it.
Just when I was full of doubts, my father came over and asked, "What's the matter? What are you thinking about? You are big. "
"what! My head is not big ... "Then, I'll tell you what just happened.
"Oh, I see. Don't you know that it is a truth that a chopstick is broken and a chopstick keeps breaking! "
Little ants know how to unite, we can't lose to ants!
A few days ago, the teacher asked us to go home to soak beans and observe the daily changes of beans.
I grabbed a handful of beans from the refrigerator, detected them as bad, and put them in a cup and soaked them in water.
When I changed the water the next day, I found that the beans were swollen, like children who drank enough water. There are some small wrinkles around the radicle.
On the third day, a small bag appeared on the radicle, and the wrinkles around it disappeared and became the head of a little fairy. Under the guidance of my mother, I poured out the water, covered it with a 10% towel and sprinkled some water on it. According to my mother, the towel is covered to keep it moist. If beans are soaked in water for a long time, they will rot easily. After listening to my mother's words, I thought: there is so much knowledge in soaking beans.
After two days, a small bud of one or two millimeters grew on the radicle. Buds are very small, almost as thick as nails, and they get thinner as they go up.
Two days later, palmers grew into four or five millimeters of fine needles, and the dark yellow clothes turned into light yellow. Yale is as curved and beautiful as the moon. My mother told me: "This kind of bean sprouts can be fried and eaten, just like the bean sprouts sold in the market. However, it was reported on the news two days ago that there was something in the bean sprouts sold outside that made people eat badly. You see, the bean sprouts you made are safe to eat! "