Safety knowledge
Small knowledge of fire safety
First, LPG cookers should not be placed in bedrooms, offices, balconies, warehouses, auditoriums and other public places to prevent air leakage and fire.
Second, correctly grasp the use of the switch, wait for the fire, don't wait for the fire, remember to turn off the valve and switch after use, and replace the valve in time if it is broken. Don't let children use cookers or play with switches at will.
Third, when using liquefied gas, someone should look after it and stay away from it. Pay attention to adjust the size of the rotor at any time to prevent the soup from overflowing and extinguishing the flame or being blown out by the wind, resulting in air leakage.
Fourth, liquefied gas tanks should be upright, not upside down, and cannot be cooked or roasted with fire.
5. If there is air leakage, measures should be taken immediately: open doors and windows, ventilate with a fan (but not an electric fan), and then find the leaking part.
Basic knowledge of fire fighting
(1) isolation method: This is a method to eliminate combustible materials.
(2) Asphyxiation method: prevent air from flowing into the combustion zone, reduce the oxygen content in the air, and make the fire source go out under the condition of insufficient oxygen.
(3) cooling method: spray water or other fire extinguishing agents on the combustible materials to lower the temperature of the combustible materials below the ignition point and force the combustion of the materials to stop; Or spray water and fire extinguishing agent to combustible materials near the fire source to reduce the temperature of combustible materials and avoid the expansion of the fire.
(4) inhibition method.
I hope this helps.
2. Ask for a little math knowledge in the first grade of primary school.
Small knowledge of mathematics
The origin of mathematical symbols
Besides counting, mathematics needs a set of mathematical symbols to express the relationship between number and number, number and shape. The invention and use of mathematical symbols are later than numbers, but they are much more numerous. Now there are more than 200 kinds in common use, and there are more than 20 kinds in junior high school math books. They all had an interesting experience.
For example, there used to be several kinds of plus signs, but now the "+"sign is widely used. +comes from the Latin "et" (meaning "and"). /kloc-in the 6th century, the Italian scientist Nicolo Tartaglia used the initial letter of "più" (meaning "add") to indicate adding, and the grass was "μ" and finally became "+".
The number "-"evolved from the Latin word "minus" (meaning "minus"), abbreviated as m, and then omitted the letter, it became "-". /kloc-In the 5th century, German mathematician Wei Demei officially determined that "+"was used as a plus sign and "-"was used as a minus sign.
Multipliers have been used for more than a dozen times, and now they are commonly used in two ways. One is "*", which was first proposed by the British mathematician Authaute at 163 1; One is "",which was first created by British mathematician heriott. Leibniz, a German mathematician, thinks that "*" is very similar to Latin letter "X", so he opposes the use of "*". He himself proposed to use "п" to represent multiplication. But this symbol is now applied to the theory of * * *.
/kloc-In the 8th century, American mathematician Audrey decided to use "*" as the multiplication symbol. He thinks "*" is an oblique "+",which is another symbol of increase.
""was originally used as a minus sign and has been popular in continental Europe for a long time. Until 163 1 year, the British mathematician Orkut used ":"to represent division or ratio, while others used "-"(except lines) to represent division. Later, in his book Algebra, the Swiss mathematician Laha officially used "∫" as a division symbol according to the creation of the masses.
/kloc-in the 6th century, the French mathematician Viette used "=" to indicate the difference between two quantities. However, Calder, a professor of mathematics and rhetoric at Oxford University in the United Kingdom, thinks that it is most appropriate to use two parallel and equal straight lines to indicate that two numbers are equal, so the symbol "=" has been used since 1540.
159 1 year, the French mathematician Veda used this symbol extensively in Spirit, and it was gradually accepted by people. /kloc-In the 7th century, Leibniz in Germany widely used the symbol "=", and he also used "∽" to indicate similarity and ""to indicate congruence in geometry.
Greater than sign ">" and less than sign "
3. Primary school grade one topic: What is knowledge?
What is knowledge? Knowledge is defined as identifying the right and wrong of the entity and essence of all things.
Knowledge: the solidification of experience ① the achievements of human cognition. From social practice.
Its primary form is empirical knowledge, and its advanced form is system science theory. According to the way of acquiring knowledge, it can be divided into direct knowledge and indirect knowledge.
According to its content, it can be divided into natural science knowledge, social science knowledge and thinking science knowledge. Philosophical knowledge is the generalization and summary of knowledge about nature, society and thinking.
The totality of knowledge is constantly accumulated and developed in the continuation of social practice handed down from generation to generation. (2) Related to academic culture: intellectuals | intellectuals.
3 acquaintances; Friend: The court ministers are very knowledgeable. Knowledge is the link between concepts.
This is one aspect of the concept content. Another aspect of conceptual content is the connection with intuition.
In the final analysis, the purpose of our conceptual construction is to grasp intuition. Therefore, concepts must be interrelated to form knowledge.
With knowledge, you can have strength and grasp intuition. Chinese word meaning 1 The word "knowledge" means that the word speaks with the vector and the vector also sounds.
"Arrow" means "archery" and "mouth" means "talking". The combination of "arrow" and "mouth" means "talking like an arrow, talking like a bull's eye".
Original meaning: exactly right (exactly right). "I don't know" or "I don't know" is an inaccurate word, just like archery misses the bull's-eye.
Whether the arrow is accurate can be confirmed by the target reporter; Whether the words are correct or not can be tested by the public. For example, Halley, a British astronomer in the18th century, claimed that he knew the behavior of Halley's comet and predicted that it would reappear in 1759.
Later, in1759,65438+10, 2 1, people really saw this comet again. Harry is right. This is "knowledge".
2. The word "knowledge" of "knowledge" in traditional writing comes from words and sounds. The word "Xu" follows the tone of Ge, and Shuowen claims that the meaning of this word has been lost because of the teacher's interruption.
But in fact, we can understand its original meaning now. The word "Xu" originally refers to the square drill of ancient troops from sound to music.
"Sound" refers to the instructor's password sound (including drums, golden sound and soldiers' shouting and killing sound), and "Ge" refers to the soldiers and their weapons participating in the exercise. With a series of instructions from instructors, the army will move forward or backward as a whole, left or right as a whole, move forward in rows in turn, fight together to the left, fight together to the right, and so on. Looking down at the army training from the reviewing stand is like watching the group gymnastics performance from the stadium stands, and we can see all kinds of figures formed by the uniform movements of the participants.
Therefore, the original meaning of the word "virtual" is "orthomorphism and its transformation" Everything has this meaning from the word "Xu".
For example, "weaving" is to add patterns to the fabric manufacturing process to make it a printed fabric. For another example, the "national flag" is to add national patterns to the flag cloth as a national symbol. For example, the flag of China has a five-star pattern, the flag of the United States has a star stripe pattern, and the flag of Britain has a herringbone pattern, and so on.
For another example, the "post" is a team gymnast, whose task is to receive instructions with his ears and then make the required actions. The result of each participant's doing this is that group calisthenics can change all kinds of graphics.
To sum up, we give the original meaning and extended meaning of "knowledge" here. Original meaning: describe the shape and details of the pattern in language.
Extended meaning: difference, discrimination. For example, "literacy" means "recognizing characters according to their glyphs, structures and strokes".
3. The original meaning of the word "knowledge" in Chinese: it refers to academics, culture or learning.
4. Basic knowledge of primary school music
Summary of music theory knowledge in the first grade of primary school: 1. Master the rhythm of songs, understand the staff or notation scale, learn to rap and correct the pitch. 2. Be able to read the difference between the fourth and eighth tones. 3. Feel the difference between two beats and three beats. 4. Listen to the length of the sound. Grade two: 1. Learn to gesture. Know simple notes. 2. Understand weak notes. 3. Know the supplementary points. 4. Understand the repetitive tags and their functions. 5. Know the alphabet and sing the melody by name. 6. Understand stress symbols. Grade three: 1. I know music and can sing. 2. Know the time value of a single note. 3. Know the lifting signs and master their functions. 4. Consolidate weak notes. Sing some notes accurately. 6. Know the octave rest in the staff. Level 4: 1. Entering the two-part training, you can know the score of the whole song, listen to the rhythm of percussion and record it. You can create your own rhythm. 2. Know quarter notes, quarter notes, pause marks, connecting lines, rising numbers and strength marks. And can briefly describe the meaning of music. 5. Understand the simple knowledge of music composition, interlude and musical instruments. Level 5: 1, master the special rhythm in the song (six beats and time signs). 2. Accurately sing decorative sounds and marker sounds. 3. Enjoy music from your own point of view. 4. Sing the two-part chorus well and improve the chorus performance ability. Sixth grade: 66. You can accurately sing the drama pieces that you are required to master this semester. 2. You can enjoy more tracks and cultivate students' deep appreciation ability. 3. You can master the simple gestures of the second beat, the third beat and the fourth beat. 4. Rhythm can be carried out at the same time as the main training rhythm and beat. 5. You can know and understand western musical instruments and national musical instruments.
5. knowledge of nature test questions for primary school students
1. A tree can absorb 14.5 kg of carbon dioxide and produce 1 1 kg of oxygen in a year.
. 2. Salt has the function of removing odor and whitening the toilet, and it is a very easy-to-use natural cleaner.
When operating the computer daily, you must wash your face after using the computer. The distance between the body and the computer screen should be no less than 70cm.
4. Cabbage, spinach, celery, carrots, peaches, grapes and apples are suitable for storage at 0℃.
5. tomatoes, cucumbers, persimmons, chestnuts, etc. It's best to put it in the drawer of the refrigerator, not for a long time.
6. Suitable storage temperature for bananas, lemons and pumpkins. It is 13℃~ 15℃, and it is easy to turn black and rot when stored at low temperature. Ham, chocolate, bread and so on. It shouldn't be in the refrigerator.
7. Knowing that there is pollution at home can attract your attention. The following are common and easily overlooked household pollution.
8. Don't use alkaline solution to clean stainless steel tableware.
9. Frozen cooked meat should be heated before eating.
10. Don't put the dry-cleaned clothes on your body immediately, but hang them in a ventilated place, and wear them after the harmful gases are fully emitted.
1 1. When using the water heater, be sure to keep indoor ventilation.
12. Water stored in containers for more than three days is not suitable for drinking.
13. In order to maintain human health and normal development, the indoor sunshine time must be more than 2 hours every day.
14. When the clear height of the room is less than 2.55m, the indoor carbon dioxide concentration is high, which is harmful to the indoor air quality.