Ever wondered about the science behind the little things that we notice in our lives but are too lazy to google about them? From wondering why we are not able to recognize our voice in sound recordings to trying to understand why our hair turns lighter and skin darker in sun? Well, we have answers to all these questions right here.
#1 Why the grass smells so nice?
The smell of freshly cut grass smells so amazing. But the reason behind this smell is not so amazing. To put in one word, the smell is trauma. When the grass is cut, organic compounds called green leaf volatiles (GLV) are released in a much higher amount than usual from the plants.
These GLV compounds are released to help the plant in closing the wound where the grass is cut so that it avoids fungal growth. Some of the compounds aid in the formation of new cells while others act as distress signals.
For humans, the GLVs are pleasing to the nose. The group of eight, related, oxygenated hydrocarbons along with alcohols and aldehydes cause the “green odor” that we smell after the grass is freshly cut.
However, this “green odor” comes at a cost as the GLVs form “bad” ozone that is detrimental to the environment and is the main component of photochemical smog in the atmosphere. (source)
#2 Why we don't like ourselves in the photographs
The photographs we see are in reality the flipped mirror images of us. We are actually so used to seeing ourselves in the mirror that our snapshots don't look right to us. Well, there is science behind this too. Actually, human faces are not symmetrical, where one eye or ear might be slightly bigger than the other, or we may have a mark or mole on our faces.
Some people part their hair on one side which is what they prefer, but the photographs show it flipped making the image look odd.
When you look at a photograph you expect to see a certain image of yourself that stems from the memory of your face in the mirror. You don’t see what you expect which leads to disappointment, and you don’t like how you look in the photograph.
Meanwhile, your family and friends like your photograph and find nothing wrong with it because this is how they view you every day. This all boils down to expectations. (source)
#3 Why soda and soft drink bottles are different
When the soda or soft drink bottles were engineered, two major things were kept in mind. The design of the bottles was not made so for looks. One reason is the bottle must be able to withstand the change in volume that occurs when the chilled liquid increases in temperature and shouldn’t topple.
The second reason is it should be able to resist the process where the bottles are pressurized to fill the gas as the drinks are carbonated.
A “five-pointed” corrugation in most of the soda bottles makes them stronger. When you try to crush the top of a soda or soft drink bottle, it is easier to do so than to try and crush its bottom, as the latter has stronger resistance to force.
The bottles become narrower towards the top to improve stability. In case of water bottles and juice bottles, since they are not pressurized, they don’t have as many bumps as soda bottles. However, even water bottles have small indents on the bottom to improve stability. (source)
#4 Why does standing for long makes our legs sore?
Walking doesn’t make our leg muscles as sore as compared to when we are standing in one place for long. There is a reason behind it. When we stand, the calf muscles in our legs are under great pressure as they take all the weight.
This tires the legs out as opposed to when we are walking when other muscles in the thighs, buttocks, core, and arms share the burden with the calves. Standing also tires the feet. Also, our legs do not get a break, as none of them are off ground for even a second when we are standing, but when we walk, the legs get a quick break alternatively.
Standing still can hinder the heart from pumping blood efficiently. This is one reason why our feet swell after long periods of standing. While walking, the muscles contract which helps the heart to pump blood. These were the physiological aspects.
And to point, there is a psychological aspect to it too. While standing, as we are stagnant in one place as opposed to walking when the sights around us keep changing, we tend to get bored and focus more on the pain and tiredness in our legs. Walking is also known to release endorphins, the feel-good neurotransmitter. (source)
#5 Shampoo always turns white in the shower
There is a scientific reason behind this too. The pigments in the shampoo when mixed with water, become so thin that the visible light gets scattered. As a result, the reflected light rays are dispersed in several directions after striking a surface (bubbles in this case) much like how the sky appears white or grey at times.
Also, the dye that is used in coloring shampoo is highly diluted, which means that when further diluted with water, the color becomes much lighter.
The scattering of light in the case of the foam happens as the light has to pass through several bubbles, which means several surfaces. The light spreads in multiple directions making it almost impossible for the human eye to detect colors. The same thing happens with soap bars, body washes, hand washes, etc. (1, 2)
#6 Blown-out candle gives out more smoke
There are two parts to a candle: the wax and the wick. The wick is the thread-like thing that sticks out and which we light with a match. The wax is the fuel that burns producing light through the capillary action of the wick.
When the candle is burning, we do not see smoke coming out of it. However, when it is blown out what we notice is not smoke but in fact, vaporized paraffin wax that was acting as fuel. The candle wax is not just melting, it is also vaporizing.
The vaporized paraffin wax is to candle wax what steam is to water. When we blow out a candle, some heat due to combustion remains in the wick. This heat continues to vaporize the candle wax for a few seconds.
As there is no flame, the wax doesn’t burn properly and condenses in the colder air around the wick forming the smoke which stops after a few seconds and turns solid. Try an experiment of blowing out a candle and re-lighting it through the smoke without touching the wick. It acts as conclusive proof that the smoke is indeed vaporized candle wax.
#7 Men burn fat faster than women
A study that was published in the journal Diabetes, Obesity and Metabolism talked about how 2,200 overweight adults from Europe, Australia, and New Zealand were put on an 800-calorie diet for eight weeks.
By the end of the 8-week period, it was noticed that men lost 16% more weight than women. Apart from this, a number of other not-so-good results were also observed in women including a decrease in HDL cholesterol, bone mineral density, and lean body mass, all of which can cause a slow metabolism.
The reason why men lose weight faster than women is that men are physiologically built to burn fat faster. They have a higher metabolic rate and lean muscle mass that consumes more calories.
Because men have a higher metabolic rate, they need to consume more calories. In the case of the study mentioned above, as both men and women consumed an equal amount of calories, a larger calorie deficit was created for men which resulted in the shedding of more kilograms. (source)
#8 Why does skin turn dark and hair lighter in sun?
Both our hair and skin have a pigmented polymer called melanin. This pigment is our protection from the ultra-violet (UV) rays of the Sun. Melanin is responsible for absorbing and scattering UV rays, but in case of prolonged exposure, it degrades.
Our skin cells react to the UV rays causing the body to produce a hormone that binds to melanin-making cells. This makes the skin produce more melanin which becomes darker as it disperses from the lower layer of the skin to its upper layer. This is what darkens our skin and causes a suntan.
For our hair, since the cells are dead, new melanin in return is not produced In once the melanin that is already present is exhausted.
The hair cells are comprised of structured proteins, lipids, water, and pigments which in no way help the hair retain its original color. So, the hair gets lighter under the Sun and remains that way until they are cut and new strands grow in the place of the damaged, lighter ones. (source)
#9 Why we don't recognize our voice in recordings?
Well, it is very common to not recognize your own voice in recordings. There is a scientific reason behind this too. When we hear people talk, the sound waves travel through the air and they vibrate in our eardrums.
The same thing happens when we hear our own voice in addition to another thing. Our vocal cords vibrate when we speak, and these vibrations are a second source of sound for us. So, when we speak, what we hear is a combination of these two sounds.
When we hear a recording of our voice, the only thing we hear is the external stimulus and not the vocal cord vibrations making it sound very different to us, almost unrecognizable as we are not used to hearing it.
According to a study, when people heard recordings of their own voices, only 38% were able to immediately identify their own voice. The recording of our own voice is at a higher pitch and does not have a false sense of bass like the one we have when we hear ourselves speak. (1, 2)
#10 Why do fingernails grow faster than our toenails?
Our fingernails grow two to three times faster than our toenails. There are a lot of similarities between our fingernails and toenails. Both have a distal matrix (below the cuticle) from where new nails grow.
The distal matrix has epithelial cells which die over time and leave behind the protein keratin. A key enzyme called transglutaminase is mixed with keratin and other proteins and fats which then grows into a hardened nail. However, the growth patterns of the nails in the toes and the ones in the fingers are different.
One popular theory for the slower growth of toenails is that lesser blood blow reaches the feet than the hands resulting in lesser oxygen and nutrients for the growth of new cells in the toenails’ distal matrix. We also tend to cover our feet in socks and shoes reducing circulation.
Another theory is that our fingernails undergo more trauma than our toenails as we use our hands more and for a variety of tasks. The trauma caused brings about an increase in the growth of the epithelial cells which results in more growth. It has also been observed that as we age, our nail growth slows down by around 30%. The growth also slows down in the winter. (source)