7. If you mix water and sawdust and freeze it, the resulting “ice” melts extremely slowly, like “weeks at room temperature” slowly.
Want to make a material that is nearly as tough as concrete and can float on water? Well then, in a container add 14% sawdust and 86% water by weight and let it freeze. Once it is completely frozen, you will get the toughened ice known as “Pykrete.” Pykrete was invented during World War II by British molecular biologist Max Perutz. The material was noted for its relatively slow melting rate. Being almost as tough as concrete yet possessing the ability to float on water, Pykrete was proposed as building material for an aircraft carrier. Since there was a shortage in the supply of steel and aluminum, the project for a pykrete aircraft carrier, Project Habakkuk, was given a green light. A small-scale prototype was built in 1944, but later the project was shelved.
Pykrete is a bit difficult to form as it expands during freezing. It can be repaired and maintained by using seawater. Pykrete can be frozen into any shape, and it will be tough and durable as long as it is kept below freezing temperature. It has the crush resistance of greater than 21 megapascals. That’s why even a 25 by 24 mm column of pykrete can support the weight of a typical car. Apart from sawdust, Pykrete can also be formed using shredded paper. (1, 2)
8. Blind people don’t see black.
Blind people in most cases get some visual inputs which range from being able to perceive very bright lights to about a 20/2000 threshold of vision. A person who is completely blind and has no light perception at all is actually quite rare. Surprisingly, these people cannot see black or what we call “pitch darkness.” Sight, whether it’s light or darkness, is a signal that the eye sends to the brain. In the case of blind people with no light perception, the pathway from eye to brain is blocked or severed. So, basically, they see nothing. Sometimes people who are totally blind might see flashes of color or light that aren’t there. This is a biological glitch, and it looks like the flashes of light that people with normal vision temporarily see when they get hit in the head.
BBC journalist Damon Rose who lost his sight as a child has one of the rare blindness – no light perception. When asked what replaced the 3D technicolor vision once the total blindness took over, he said, “Light.” He said his vision has been replaced by colorful, bright, and ever-changing light. Often these lights turn out to be distracting, and according to him, he rather misses not being able to see darkness. He also mentioned that he doesn’t know whether other people with no light perception can also see the same thing. (1, 2)
9. Earth’s atmosphere extends out to as much as 630,000 kilometers and actually extends beyond the Moon.
Earth‘s atmosphere is divided in five layers, and the outermost layer is known as “exosphere”. The outermost layer of the exosphere is the geocorona, a cloud of hydrogen atoms that is luminous in ultraviolet light. The geocorona is very thin and hence hard to measure. According to previous records, it was believed that the upper limit of the geocorona is around 200,000 kilometers from Earth. But a recent data achieved from Solar and Heliospheric Observatory (SOHO) has revealed that it extends out as much as 630,000 kilometers, which means even our moon is inside the Earth’s atmosphere.
The surprising thing is that the data from which this conclusion had been derived is not a recent sampling. SOHO made these observations between 1996 and 1998. The data was archived and this amazing fact about the geocorona has been deduced recently. It was made public on February 20, 2019, by the European Space Agency (ESA). The data have been provided by SWAN, one of the instruments of SOHO. SWAN’s sensitive sensors have successfully traced the border where the hydrogen of geocorona dwindles into nothing. (1, 2)
10. There exists a banyan tree in Howrah, India that is bigger than the average Walmart.
Founded in 1786 by Colonel Robert Kyd, the Acharya Jagadish Chandra Bose Indian Botanic Garden is located near Kolkata, India. The most famous landmark of this garden is The Great Banyan Tree which is over two hundred and fifty-five years old. Spreading over 14,500 square meters of land, it is the widest tree in the world. The area covered by the tree is so huge that it is even greater than the size of an average Walmart store (9,750 square meters). The size of this banyan tree has even gained it a place in the Guinness World Records.
The Great Banyan Tree has over 4,000 prop roots which give it the appearance of a forest when viewed from a distance. Over the years, the tree has been through a lot. It has survived two major cyclones in 1864 and 1867. In 1925, the main trunk was lost to a fungal infection. Surprisingly, the prop roots have kept the whole tree alive. In 1985, fencing was done around the tree, but it soon outgrew and even crossed the metaled road surrounding it. The tree is still growing and is steadily spreading out to the east. (1, 2)
11. Chameleon bones glow in the dark under ultraviolet light even through the skin.
If you were amazed by the color-changing ability of chameleons, then you will love them for their recently discovered characteristic – glowing in dark. Light-emitting characteristics are common in deep-sea creatures, but biogenic fluorescence is rare in terrestrial vertebrates. This new discovery came to light when a team of German researchers published their paper on January 15, 2018. They tested 31 species of calumma chameleons and revealed that when viewed under ultraviolet light, the chameleon’s skeleton shined through their skin.
Chameleons have four layers of skin which help them in changing colors. Upon shining the UV lights on the bones, they began to glow through the skin and revealed a previously invisible pattern on the head. On some species, the pattern (also known as “tubercles”) was present over the whole body. Scientists also found that the number of tubercles in males is more than the females. (source)
12. Gold and silver worth three million francs end up in sewers of Switzerland each year.
What if tons of precious metal started flowing through the sewers of your locality? You probably would start sieving through the sludge right now. As improbable as it may sound, this is the reality in Switzerland. In 2017, a study revealed that 43 kg of gold and 3,000 kg of silver end up in the sewers of Switzerland every year. The amount of gold and silver that goes into this wastewater is worth three million francs. This study was commissioned by the Swiss Federal Office, and the result was derived after researchers evaluated the sludge from 64 wastewater treatment plants. Apart from gold and silver, other rare metals were also found including gadolinium, neodymium, ytterbium, ruthenium, and rhodium.
A large portion of these elements enters the wastewater in regions where factories and refineries are situated. Gold and ruthenium were found mostly near watchmaking industries. Tech and medical fields use gold, silver, and copper which contributes to the presence of these metals in the sewage near their location. A high concentration of gold was found in the sewage of Ticino. It’s probably due to the presence of several gold refineries in the area. According to the researchers in most places, recovery of these metals is not economically worthwhile. (1, 2)