Category Archives: Biology

Can humans eat grass?

Let us assume that we are a victim of some disaster and we have run out of food supplies. Can we eat grass to survive? In theory, yes – grass is non-toxic and edible. Unfortunately, in practice, eating grass will do us more harm than good.

There are two problems with eating grass. The first is that human stomachs are not adapted to digest raw leaves and grass. As a result, if we eat grass, we won’t absorb any nutrients from it, but only irritate the stomach, which can lead to problems such as dehydration caused by diarrhea. Raw grass can also be a source of germs, which will make our situation even worse. Finally, we may also pick some other plant along with the grass, which may even be poisonous. Animals, such as cows, can eat grass because they have stomachs with four chambers.

The second problem with eating grass is chewing it. Raw grass contains a lot of silica, which abrades the teeth. In animals adapted to eating grass, teeth grow slowly all the time, renewing the worn surface. For us, the dental clinic will be of necessity.

To get the most out of the nutrients in grass, it would have to be cooked. However, this actually is pointless. If we are not in a crisis, we have no need to eat grass, and if we are (e.g. if we have lost our way), we are unlikely to have a pot with us. Well, and even if we did, in the best case we would get a decoction resembling tea and its nutrients would be minimal.



Foraging Survival Foods

Can You Eat Grass to Survive? What Does It Taste Like?


Can a pocket laser damage our eyesight?

Can a pocket laser damage our eyesight? The answer to this question depends on many factors. It is a bit like trying to establish a single safe speed for driving a car. Under normal conditions, a speed of 30 mph is safe, but not during storm or heavy fog. It is similar with defining the safety limit for the laser pointer. The likelihood of eye damage depends on many factors. It includes the laser color, divergence (beam dispersion), distance from the source, the time our eyes are exposed to it and, above all, power. It is the power that is the main determinant of marketability. Depending on the country there are different standards (with divisions into special classes), but generally lasers up to 5 mW are considered to be the upper safe limit. In the United States the limit is 3.5mW.

The power of lasers is given in milliwatts (mW). Theoretically, 3.5 mW is a safe value because it represents about one-tenth of the actual damage threshold, but history records cases of permanent vision damage from a pocket laser. Why? First, there are cheap Chinese products on the market the power of which may differ from that declared on the housing. Second, users of the laser may be children. In 2018, a 9-year-old became blind in one eye by looking into a green laser beam several times.

Why worry about 5 mW at all? After all, it’s only 5 thousandths of a watt, or less than one percent of one percent of the power of a 60-watt light bulb. The reasons are two. First, a light bulb converts only about 10 percent of that energy into light (the figure is different for an energy-saving bulb). Second, the bulb shines in all directions, thus we see only a small portion of the light it emits. We reduce this amount even further by moving away from it. A laser emits light in one small focused beam.

Despite meeting safety requirements, small lasers can still be dangerous. The reason for this is known as flash blindness. Everyone knows the feeling of temporary blindness after a camera flash or after moving from a dark to a bright room. A laser beam can lead to such temporary blindness, which can have extremely severe consequences for e.g. drivers, or machine operators. There are known cases of attempts to blind airplane pilots. The effect is particularly strong at night, when pupils are dilated. Lasers are also used during protests and riots. They are used to damage drones, CCTV cameras and to blind police. IR (infrared) and UV (ultraviolet) lasers are particularly dangerous. Normally the eye exposed to a laser should blink in reflex, but UV and IR rays our body is not able to detect. Recently, lasers were used in the riots following the death of George Floyd. Three officers were blinded by lasers (authorities report that permanently).

Regardless of the power, lasers should be used with caution and under no circumstances should a child be allowed to play with them.


Lasers: The Future of Protests

Why do some people have dimples in their cheeks?

Dimples are small depressions found in various areas of the body, including cheeks, chin and lower back. They are commonly considered an appearance feature that adds to attractiveness. In this article, we will try to answer the question why dimples are considered attractive, how do they appear and what is their function?

Cheek dimples

Dimples in cheeks are caused by a specific structure of facial muscles, specifically the zygomaticus major. This is the muscle responsible for smiling – when we smile it pulls the corners of our mouth up. Normally, the zygomaticus has two attachments – one above the corners of our mouth and the other on the zygomatic bone (cheek, on the outside of the eye socket). However, people with dimples have a third attachment – to the inner skin of the cheeks. When such a person smiles, the muscle pulls the cheek skin attached to the muscle, forming dimples.

As cheek dimples develop during the fetal period, they are sometimes mistakenly referred to as a birth defect. Although cheek dimples have no biological function, they also have no negative health effects. They simply are, just because they are.

Zygomaticus major muscle (wikimedia commons)

A chin dimple (cleft chin)

Dimples in chin most often appear due to the jawbone structure. The mandible is formed during the fetal period, fusing together from two parts: the left and the right. If the halves do not fuse together completely, it causes a small dimple to form at the junction. As with cheek dimples, this has no biological significance.

In some cases, the chin muscle is responsible for the dimple.

Dimples above buttocks (Venus dimples)

Venus dimples are tiny depressions above the buttocks. They are located in the area of lumbar region completely devoid of muscles. They are most commonly found in women, but some men also have them. In this case we refer to Apollo dimples. As with facial dimples, Venus dimples have no biological significance, although some researchers suggest that dimples above the buttocks indicate better blood supply to the intimate area, which may have a positive effect on sexual experience.

Why are cheek dimples considered attractive?

There are two reasons. First, dimples accentuate a smile, making it appear more sincere and joyful. Second, they look adorable because we associate them with a baby face. Some studies suggest that the presence of dimples can convey more information about the intensity of facial expression.

Can you get dimples in your cheeks from exercise?

Unfortunately, no. Exercising your facial muscles will improve your facial contours and overall appearance. However, it does not make dimples appear by any means. The only solution is a procedure called dimpleplasty. Your physician will make a small incision on the inside of your cheeks through which he will cut a small piece of muscle and remove a bit of fatty tissue, then place a suture connecting the skin to the muscle. The suture is dissolvable, so you will not need to make additional visits to have it removed. In place of the suture, a scar will appear to permanently connect the skin to the muscle. The procedure is very simple and the chances of complications are relatively low.

Cleft chin correction

When it comes to chin dimples, it is a completely different matter. Although in most cases they are celebrated positively, in some cases they can cause disruption to the symmetry of the face. The dimple may be too deep, or unevenly placed. In this case, it is essential to consult the physician. He must determine the cause of dimple and suggest a method of correction. The simplest is to use a filler – hyaluronic acid. Such a procedure takes several minutes and is almost painless. If muscles are responsible for the problem, the physician may recommend an injection of botox, i.e. botulinum toxin. This substance paralyzes the muscles, which will reduce their tension and loosen the pulled skin. Depending on the substance used, the treatment will have an effect of several months to two years. A permanent option is chin surgery. Depending on the need, the physician may file the excess bone, fill the gap with a special implant, correct the muscle position, or use a combination of the above methods. The disadvantage is a long convalescence. There is also a price difference. A cosmetic procedure costs from $200 to $400, whereas a surgical intervention involves the cost up to $2,000.


Is it dangerous to take a shower during a thunderstorm?

Yes – if you take a shower during a thunderstorm, there is a risk of electrocution. To understand why, we need to remind ourselves how electricity behaves. If lightning strikes a house, the electricity will follow the path of least resistance, which is the best conductor available. This can (and should) be a lightning conductor, but even in its absence, the electricity will find some path. Many things can be used as conductors: metal gutters, plumbing pipes, or even reinforcement elements provide an excellent escape route to the ground. Thus, when lightning strikes, the current will flow through one of these available conductors until it reaches the ground and dissipates. The occupants will remain safe. But…

Well, there is always a “but.” If you are taking a shower during a thunderstorm, or even washing your hands when lightning strikes, you can become a conductor of electricity. The current will flow through the water pipes, and our wet body standing in the shower will close the circuit between the shower and the drain with which the water pipes have no connection. There are several documented cases of such a shock. This is why, despite the small chance of such an occurrence, experts recommend avoiding contact with plumbing during a storm. We don’t wash plates, shower or bathe. For our own safety.


How long can you survive without food?

How long is it possible to survive by just drinking water and not taking any food? What is the human body’s endurance limit?

At the beginning it is necessary to point out that only an approximate time can be given, because it all depends on various factors such as: health of the starving person, body weight, genetic conditions or physical effort during the starvation.

Do we burn calories doing nothing?

Let’s start with our body. Do we still burn calories while doing nothing? Yes. Even if we lie down on a bed and close our eyes, our body is still using resources. The body has to maintain the right temperature, the muscles responsible for breathing are also working, and the most important muscle in our body, the heart, which is constantly pumping blood. All this comes at a cost in precious calories. How many exactly? It depends on our body weight, and the recommended formula to calculate our own energy expenditure is to multiply our weight by 0.02. An example reader weighing 70 kilograms burns 1.4 calories for every minute of reading this article (assuming he does nothing else at the same time). This means that for 60 minutes the body burns 84 calories and over 2000 calories in a day.

But what happens when we stop supplying calories? The body then begins to use its reserves. At the beginning goes fat tissue. The body of an average woman has 25-31% body fat and a man 18-24%. So let’s assume that our 70-kilogram individual has 20% body fat, or 14 kilograms of fat. It is estimated that 0.45 kilogram of fat is about 3500 calories. With the energy expenditure of such a person, this means losing 1/4 kilogram of fat per day. So that comes out to 53 days. However this is pure mathematics, in practice man still makes some movements. In addition, man does not live by fat alone, thus the body will start to take additional nutrients also from our muscles, which will soon be depleted. Our body takes protein from the muscles, which it uses, among others, to support the brain function.

Effects of starvation

In the initial stage of starvation, there is a significant weight loss, apathy and weakness. This period can last for about 30 days. After this time, the starving person will begin to feel much worse effects. Due to weakness of the body various infections may appear, which our body is not able to fight. Then weakness appears, with which the starving person is not even able to drink on his own. The lack of vitamins causes rashes, swelling and cracking of the increasingly dry skin. Due to muscle atrophy, any movement causes pain. The starving person is also increasingly lethargic. Beyond 40 days, the body will begin to shut down more organs. The last organ is the heart and it is its arrest that is generally considered the cause of death.

Interestingly, even the minimal amount of food taken in, extends life by up to several months. Prisoners of concentration camps and Russian camps, despite receiving starvation rations, were able to survive for a long time and at hard labor. This has to do with the yet unexplored “economic mode” of our body, in which it consumes fewer calories. It is speculated that this has to do with our body’s hormonal balance, specifically the thyroid gland.

No research has been done on starvation, but there are various historical sources about the course of such starvation.

One of the better documented cases is the 1981 Irish hunger strike, where IRA members went on hunger strike in protest. Most of the protesters were relatively young: the youngest was 23 and the oldest 30. The first death occurred after 46 days. The longest survivor was 25-year-old, Kieran Doherty. He survived for 73 days. These events are shown in a film entitled “Hunger.”

Much older in age was Mahatma Gandhi, who at the age of 74, conducted one of his hunger strikes in protest. It lasted 21 days. It is also worth noting that Gandhi had 14 such hunger strikes in his life.

Longest starving person

The longest starving person was a Scot who in 1965 decided to lose weight in a very drastic way. Under the supervision of physicians he starved himself for 1 year and 17 days. It was not a full-fledged starvation, because the patient received a small portion of yeast and a set of essential vitamins and minerals – a total of about 60 calories. However, even this small amount proved to be enough to keep the 27-year-old in good shape. After 382 days, Angus Barbieri had reduced his weight from 207 to 82 kilograms.

Starvation is also a religious ritual. The most extreme example is Sokushinbutsu which means self-mummification. Buddhist monks, for almost three years ate only nuts and seeds, while doing physical exercise. Then, for another three years, they fed on roots and herbs to induce poisoning of the body. In this way, the monks systematically supplied their bodies with ingredients that were used to embalm their future corpses. Finally, the monk was locked in a special cave, where he sat in the lotus position, awaiting death.

Mumified monk (Wikimedia commons)

Starvation was also one of the methods of execution. However, it usually went hand in hand with a lack of water, so death was quicker – after just a few days.