- Put a cup of hot water and a cup of cold water in the refrigerator at the same time, who freezes fast?
People usually think that if a cup of cold water and a cup of hot water are put in the refrigerator at the same time, the cold water will freeze quickly. However, it is not.
One day in 1963, in a middle school in Tanzania, a student named Erastor Mpeba added sugar to hot milk and prepared to put it in the refrigerator to make ice cream. He thought, if you wait for the hot milk to cool and put it in the refrigerator, other students will fill the refrigerator, so they put the hot milk in the refrigerator.
After a while, he opened the refrigerator and found that his cup of hot milk had turned into a cup of delicious ice cream, while the ice cream made by other students with cold water had not frozen. His discovery did not attract the attention of teachers and classmates, on the contrary it became their joke.
However, Mpeba told this special phenomenon to Dr. Osborne, a professor of physics at the University of Dar es Salaam. Osborne was also a little surprised after listening to Mpeba's narrative, so he conducted another experiment, and the result was exactly the same as Mpeba's narrative. This definitely confirms that in a low temperature environment, hot water freezes faster than cold water.
Since then, many scientific journals around the world have introduced this natural phenomenon and named this phenomenon "Mpemba Effect" (MpembaEffect). Have you gotten this phenomenon that breaks through common sense?
- Sheep belong to the bovid family
Haha, this point is not only cold, but also looks like irony.
However, it is absolutely true. Please remember that in the biological classification, sheep belong to the family Bovidae, Chordata, Mammals, Artiodactylidae!
- The lighter was invented earlier than the match
Most people think that lighters are much more advanced than matches, so the invention of lighters must be later than matches. However, the fact is just the opposite. The lighter was invented in the 16th century, and the match was invented at the end of the 18th century. The invention of the lighter predates the match.
According to data, the lighter drawings first appeared in a hand scroll owned by a nobleman in the Nuremberg region of Germany in 1505 AD.
- Polar bear's hair is transparent
You read that right! The fur of the polar bear is not white, but transparent!
U.S. scientist Mallim Henry, who specializes in polar bears, once analyzed the "white hair" of polar bears through a scanning electron microscope, and was surprised to find that the fur of polar bears is not white, but hollow and transparent tubes.
The "white" seen by the human eye is formed because the inner surface of the hair is rough and uneven, so that the light is refracted very messy.
- Spicy is not the taste but the pain
The sensation of hotness is produced by capsaicin and other receptors that act on the headache fibers of the tongue. This pathway is actually a pathway for pain, not a pathway for taste.
Therefore, from a neuroscience point of view, spicy is actually a kind of pain. To explain it in more common terms, capsaicin stimulates the pain nerves of the taste buds to make us feel burning pain, which is the source of the spicy sensation.