July 2023 "Science" Rumors List: Is tap water undrinkable after a heavy rain? The bigger the head, the smarter it is?

1. Thick yogurt is more nutritious

gossip

The thicker the yogurt, the better the quality. Thinner yogurt is less nutritious because it contains too much water.

(Photo source: Visual China)

the truth

The nutritional value of yogurt has nothing to do with its consistency.

From the perspective of production technology, yogurt can be divided into two types: coagulated type and stirred type. The coagulated type is to directly put milk and fermentation bacteria into the yogurt cup for fermentation. Generally, coagulants such as xanthan gum are added to make the yogurt into blocks, such as the bowl-packed and canned "old yogurt" commonly seen on the market; while the stirred type is first fermented in a fermentation tank, and then filled into the cup after fermentation is completed, such as most cup yogurt, and its texture is thinner than the coagulated type.

Some people think that thickeners in yogurt, such as xanthan gum, gelatin, carrageenan, etc., are harmful to health. In fact, these concerns are unnecessary. In fact, these food gums are regular food ingredients. The so-called "thickening" is also very common in traditional foods, such as "thickening", which is to use starch to increase the viscosity of the soup. Jelly is also an edible gum formed by similar carbohydrates. The amount of food additives from regular manufacturers will be within the safe range, and thickeners will not cause blood viscosity.

2. The darker the color of the sunglasses, the better the eye protection

gossip

The darker the color of the sunglasses lenses, the more they can protect your eyes from UV damage.

(Photo source: Visual China)

the truth

The depth of lens color will only affect the degree of absorption of visible light and has nothing to do with UV resistance. The lens material is the key factor affecting the UV resistance of sunglasses. The darker the color, the stronger the UV protection function.

Ultraviolet rays can be divided into short-wave ultraviolet rays (UVC, 100-280nm), medium-wave ultraviolet rays (UVB, 280-315nm), and long-wave ultraviolet rays (UVA, 315-400nm). The main source of ultraviolet rays in nature is the sun. When sunlight passes through the atmosphere, ultraviolet rays with wavelengths shorter than 290nm are absorbed by the ozone layer in the atmosphere. Therefore, all UVC and most UVB are absorbed by the ozone layer. The main impacts on the human body are UVA and some UVB.

Whether sunglasses can block ultraviolet rays is mainly determined by the UV (ultraviolet) standard of the lens. For example, UV400 lenses can block 100% of ultraviolet rays, and UV100 lenses can block 96% to 98% of ultraviolet rays. Consumers should carefully check the labels of anti-ultraviolet sunglasses when purchasing them. The UVA and UVB labels should be indicated on the labels of anti-ultraviolet sunglasses. Products without such labels do not have anti-ultraviolet function.

Sunglasses without UV protection and with dark colors are actually more harmful to the eyes because dark glasses will make our vision darker and the pupils larger, so more UV rays will pass through the pupil area, and the damage range to the lens and retina will become wider, which can easily induce glaucoma and cataracts.

3. Eating soy sauce on wounds will leave scars

gossip

During the wound healing period, do not eat dark-colored foods such as soy sauce, otherwise the new skin will turn dark and leave scars.

(Photo source: Visual China)

the truth

Whether a scar will be left after the wound heals has no direct correlation with soy sauce. Whether a scar will form and the size of the scar are affected by factors such as individual constitution, wound location, severity and healing. In the process of wound healing, the ingredients in soy sauce do not participate in it, nor will they have any impact on it, and pigments will not be deposited in the scar tissue.

The black color of soy sauce comes from the caramel pigment it contains. Even if it is absorbed by the human body, it will not be transported to the skin. Soy sauce's "suspicion of being involved in black" also comes from its two ingredients, amino acids and tyrosinase. Among them, the amino acid component of soy sauce will not promote the formation of melanin; tyrosinase cannot tolerate strong acid. Regardless of whether soy sauce contains tyrosinase, it will be inactivated by gastric acid when entering the stomach and lose its biological activity that can catalyze chemical reactions. Therefore, it is just a rumor that eating soy sauce will make wounds black.

4. The bigger the brain, the smarter it is

gossip

The bigger the head, the more brain cells a person has, and the smarter he is.

(Photo source: Visual China)

the truth

The ability of the brain actually depends on its sulcus area and the connections between brain regions. It is not a simple "the bigger the smarter". Many cases can be seen clinically. Although the patient's brain is larger than the normal brain, it is not well developed, and its internal efficiency is very low. The sulcus area, volume and connection between multiple brain regions of the brain cannot be compared with the normal brain. In a narrow sense, "big brain" actually refers to the large capacity of the brain. The larger the capacity, the richer the sulcus area per unit volume, and the more brain resources can be mobilized for memory or thinking. Therefore, the essence of a good or bad brain is actually more brain cells and richer connections between brain regions. "The bigger the head, the smarter" cannot be generalized.

5. The more sour the fruit, the higher the vitamin C content

gossip

The sourer the fruit, the higher its vitamin C content.

(Photo source: Visual China)

the truth

Judging the vitamin C content in fruits by the sweetness or sourness of the taste is not a reliable method. A sour taste does not mean that the vitamin C content is high. In fact, the sourness of fruits does not come from vitamin C, but is determined by the organic acids in the fruits. If the vitamin C content is judged by acidity, then lemons should contain a lot of vitamin C. However, the latest version of the "Chinese Food Composition Table" shows that every 100 grams of lemons contains only 22 mg of vitamin C. In comparison, every 100 grams of Chinese cabbage contains 64 mg of vitamin C, which is about three times that of lemons.

6. The bigger the number on the bottom of the plastic cup, the safer it is

gossip

When choosing a plastic cup, pay attention to the number marked on the bottom. The larger the number, the safer it is.

(Photo source: Visual China)

the truth

This statement is not accurate. In fact, as long as it is a regular and qualified plastic product, it can be used with confidence. Most plastic containers have a number icon at the bottom, the numbers are usually 1-7. This is an internationally common plastic classification. Different numbers indicate different materials of plastic, not safety indexes.

No. 1 Polyethylene terephthalate (PET), plastic bottles for mineral water, juice, and carbonated drinks are made of it; No. 2 High-density polyethylene (HDPE), common barrels for bottled water are made of it; No. 3 Polyvinyl chloride (PVC), the plastic used for general plastic pipes; No. 4 Low-density polyethylene (LDPE), common wire and cable adhesives and films are made of it; No. 5 Polypropylene (PP), this is the most heat-resistant material, it is often used in plastic utensils heated in microwave ovens; No. 6 Polystyrene (PS), many milk tea cup lids are now made of it; No. 7 is others, often referring to several types of plastics such as polycarbonate (PC), most infant feeding bottles use PC as raw material.

Among these materials, PP No. 5 has the best heat resistance, which can withstand high temperatures of about 200°C. It can be heated in a microwave oven and there will be no problem with repeated heating. The heat resistance of No. 1, No. 6 and No. 7 is relatively poor. It is best not to heat it directly, put too hot food in it, and never use it repeatedly.

7. The tap water in the city cannot be drunk after the heavy rain

gossip

After heavy rain, pollutants will enter the city’s water pipes, causing the tap water quality to be seriously substandard and undrinkable.

(Photo source: Visual China)

the truth

Under heavy rain conditions, pollutants will enter some urban water bodies (including reservoirs and urban rivers, etc.), but will not affect all water sources in the entire city's water source. In addition, after the water resources are brought from the water source to the water plant, they will generally go through processes such as storage, sedimentation, filtration, and disinfection to ensure that the tap water meets my country's drinking water standards. Therefore, even if some pollutants are brought into the water body by heavy rain, these effects will be eliminated during the water plant's water production process, and the final tap water will meet the drinking water standards.

8. There are fewer mosquitoes in the summer because they are “killed by the heat”

gossip

There are sometimes fewer mosquitoes during the high temperatures in summer because they are "killed by the heat".

(Photo source: Visual China)

the truth

When it’s hot, it feels like there are fewer mosquitoes. In fact, the chance of being bitten by mosquitoes is reduced, but this does not mean that the mosquitoes are “killed by heat”.

Generally speaking, the area where mosquitoes are more active and bite is 20℃-35℃. Outside this temperature range, the temperature is too high or too low, mosquitoes will be affected and restricted to a certain extent, their activity will be significantly reduced, causing the frequency of mosquito bites on people to decrease accordingly.

Climate and environment are also major factors that affect mosquito density. Good water management in various environments can effectively reduce mosquito density. It is best to change the water used for growing flowers, plants, and fish at home every 7 days. If there are bottles and cans in front of or behind the house, they should be turned over or directly discarded to avoid water accumulation. If water needs to be stored, the lid should be covered and the water should not be stored for more than 7 days.

9. When riding an escalator, you should walk on the left and stand on the right.

gossip

When riding an escalator, leaving the left side passage for others to quickly go up and down is a courteous, safe and civilized way to ride the escalator.

(Photo source: Visual China)

the truth

In fact, it is not correct to "walk on the left and stand on the right" when taking an escalator, because escalators are not suitable for walking. The height and width of the escalator steps are different from those of ordinary stairs. If someone walks or runs, it is easy to step on empty space or trip, and it is easy to squeeze other passengers during walking, causing accidents. In addition, the steps of the escalator are "comb plates" with grooves on the treads and risers. People walking on them are prone to kicking the edge of the steps and causing injuries. At the same time, "walking on the left and standing on the right" can easily lead to uneven gravity distribution, increasing the probability of escalator damage and the difficulty of maintenance.

In recent years, many cities in China have expressed their opinions and stopped the practice of "walking on the left and standing on the right" when riding escalators. Since December 2012, because the escalator steps are too large and unsafe to walk on, Shanghai Metro no longer emphasizes "walking on the left and standing on the right", and some stickers originally posted on escalators advocating this behavior have been removed; Nanjing Metro said on its official Weibo in 2016 that it does not advocate "walking on the left and standing on the right" when riding escalators; Beijing West Railway Station has also made it clear that it does not recommend passengers to "walk on the left and stand on the right" when riding escalators, but hopes that passengers "stand firmly and hold on well".

From the perspective of safe travel, when riding an escalator, please hold the handrail firmly and pay attention to the safety of your feet. Passengers who are in a hurry are safer to take the stairs and avoid walking on the escalator. After all, safety is more important than time.

10. One injection of the Internet celebrity diet pill can help you lose 16 pounds

gossip

Recently, some netizens shared that by injecting semaglutide injection, one can lose 16 pounds with one injection.

(Photo source: Visual China)

the truth

Semaglutide was originally a prescription drug for the treatment of type 2 diabetes, and it does show some effect in weight loss. On the one hand, the drug suppresses appetite by inhibiting the feeding center of the hypothalamus, so that people do not feel hungry; on the other hand, it can act on the gastrointestinal tract, delay gastric emptying, and increase satiety. However, it should be noted that semaglutide is a prescription drug and needs to be managed in full accordance with the current national management methods and measures for prescription drugs. Patients need to obtain the drug through regular hospital channels and use it under the guidance of a doctor. At present, in my country, the weight loss indication of semaglutide has not yet been approved. And whether at home or abroad, the use of semaglutide has many precautions and conditions, and it is not a "weight loss artifact" that everyone can use.

There are many adverse reactions and contraindications to the use of semaglutide. At present, the biggest adverse reaction after the use of semaglutide is gastrointestinal reaction, including abdominal distension, nausea, vomiting, diarrhea, etc. The user's mental health may also be affected, and psychological problems such as depression, anxiety, and bipolar disorder may occur.

(Sources of this issue: Science Popularization China, Science and Technology Daily, Rumor Refutation Platform, Life Times, Beijing Rumor Refutation, Beijing Science and Technology Daily, Tadpole Music, Beijing Daily, Beijing News)