Mark Twain famously once said, “It ain’t what you don’t know that gets you into trouble. It’s what you know for sure that just ain’t so.” This is so true with things that are perceived as common sense. These common sense things have been so intricately carved into our brains by our elders and society, that we do not even stop for a second to question them. What we don’t realize is that there are numerous common sense facts that are actually wrong. We bring you 10 such common sense facts that are wrong.

1 Common sense: Put ice on burns to soothe the pain and fasten the healing process.

Fact: Putting ice on burns on the skin actually slows down the healing process. The better way is to run the affected area under cool water.

Putting ice on burns is a common, first-aid activity in households. The logic is simple. Ice is cold, and cold provides the perfect relief from the pain caused by burns. But home remedies that seem like common sense are too often more wrong than right. Putting ice on burns remedy is no exception.

Although putting ice on a burn may seem to soothe the initial pain to an extent, it is not advisable in the long run. In reality, ice slows down the healing process and sometimes can even cause burns of their own.

A study published in 1997 in the Burns journal provides proof for the same. The scientists compared the relief effect from using ice with other remedies and discovered that ice caused the most severe damage. A similar study was carried out in 2002 where volunteers with first-degree burns were treated with both ice and a placebo effect. Interestingly, the ones with the placebo effect noticed more reduction in pain than those who were treated with ice.

So the best way to treat burns at home is to run cold water over them. (source)

2 Common sense: You only get sunburned when the sun is out and the weather is hot.

Fact: People can get sunburns in any season, even in snowy, cold weather. This is because sunburn is caused by UV rays, and they can pass through clouds. Also, snow reflects 80% of UV rays increasing exposure.

We think about putting on sunscreen only when the Sun is out. It is wired into our minds that the sun causes sunburn. So, when it is not out, there is no reason to worry about it. Although this seems like common sense, it is entirely wrong.

According to science, the Sun is always affecting us no matter how cold or cloudy the weather is. The reason is it is not the Sun’s heat that causes sunburns. The culprit is the UV rays, specifically the ultraviolet B rays radiated by the Sun. These rays can easily penetrate through clouds and reach the Earth’s surface. In the case of snowy climates, 80% of the rays that have reached the ground are reflected by the snow. So, people get hit two times by the rays – first directly from the sky and second when reflected by snow. A dermatology professor at the University of Wisconsin, Dr. Apple Bodemer, says, “Our atmosphere helps scatter some of the UV radiation. When you’re up at a high altitude, there’s not as much atmosphere and you will get more intense UV radiation exposure.”

So even if there’s no sun, it is always a good habit to put on sunscreen while going out. (source)

3 Common Sense: The harder you brush, the cleaner your teeth will get.

Fact: Brushing too hard can cause gum recession.

Kids with dirty teeth are often accused by their parents of not brushing hard enough. It seems just common sense that brushing hard would obviously clean the teeth better. But. that is not the case. Aggressive brushing of the teeth can actually cause more damage.

Brushing too hard leads to gum recession. This causes the gum tissue surrounding the teeth to wear away or pull back, exposing more of the tooth or its root in the process. This, in turn, increases the gap between the gum and teeth making it easier for bacteria to take hold. If the teeth are brushed too hard or in the wrong way, the enamel of the teeth wears away and causes the gums to recede. (source)

4 Common sense: Hold your breath if you run out of air during scuba diving.

Fact: This will just lead to the lungs exploding as you float upwards with a lung full of expanding air.

Never ever hold your breath when you run out of air during scuba diving even though it might seem like common sense. The consequences are quite serious but the reason is quite simple.

When a scuba diver goes underwater, the deeper he goes, the more pressure he experiences. According to the laws of physics, as one goes deeper, the pressure increases and the volume decreases. This means that with increasing pressure, the volume of the lungs gets smaller. Now, a scuba tank regulates the pressure of the air that the diver breathes in through it. The tank makes sure that the pressure of the air is the same as the pressure outside making it easy to breathe.

Now imagine the reverse process. When a diver is coming up towards the surface of the water, the pressure decreases and the volume increases. This means the lungs will now expand. So, if a diver comes back up with a lungful of air, there is no possible space available for the lungs to expand as their capacity is full. So, the only thing that can happen is that the lungs might explode. Not holding your breath underwater should be the rule of thumb for scuba diving. (source)

5 Common sense: People wear their wedding rings on the ring finger of the left hand because that finger has a vein that leads directly to the heart.

Fact: All the fingers in both the hands have a similar vein structure. The ring finger on the left hand has no special vein the goes to the heart directly.

Everybody seems to know about a special vein in the ring finger of the left hand. This is known by many people across the world. If you ask any person as to why they wear their wedding rings on that particular finger, then they would reply that it’s common sense! The ring finger on the left hand has a special vein the leads directly to one’s heart.

But this so-called “common sense” does not have a scientific backup. There is no such special vein. In reality, this myth dates back to the ancient Egyptian civilization. It traveled down numerous generations and reached the Romans who referred to this vein as “Vena Amoris” or the “Vein of Love.” The English King Edward VI declared his left-hand ring finger to be the official ring finger, and it turned to common sense after being prevalent for so long. (source)