Do birds have ears?
Did you ever try to look for birds’ ears? If you did, you probably didn’t find them. Birds’ ears are not visible, but this doesn’t mean they don’t exist, or that birds don’t hear.
Instead of bulging external ears, birds have small, feather-covered openings on the sides of their heads. These openings lead to their inner ear, and through them the birds hear what is happening around them.
Who invented the first band-aid?
Every mother warns her children not to use the kitchen knives, because they may cause injury and pain, but mothers also can get hurt by these knives. And indeed, an American woman named Josephine Dickson, who lived in the early 20th century, wasn’t so careful and often nicked her fingers. She had to prepare food for her family, so she could not avoid using her sharp kitchen knives. She had to think of some solution, even if not for preventing the injury – at least for helping the wound to heal.
She decided to affix small pieces of gauze to her fingers using an adhesive tape. Josephine’s husband was excited by the idea and decided to improve it. He showed the finished invention to his manager at the factory where he worked, and that manager decided to manufacture the new product – the Band-Aid – and market it to the public.
Why do windows get foggy in the winter?
The air around us contains a great amount of water vapors. We can’t detect them because they are colorless, tasteless, and odorless. However, in the cold days of winter we can see proof of their existence, when a thin layer of water appears “out of the blue” on the windows of our home.
What causes this phenomenon? The higher the air’s temperature, the more water vapor it can contain, and so when the air is really warm, it can contain a larger amount of water vapor. In the winter, when the warm air in the house touches the cold glass of the window, it cools down, and then it cannot hold as much water. The water vapors then turn back into water in a process called “condensation,” and this is the moisture we see and feel on the window.
What are corks made of?
Cork stoppers are, of course, made of cork, but not everyone knows where cork actually comes from. Plants are protected by a shell made of transparent cells, and when the plant reaches adulthood, this shell becomes lifeless, and thus the trunk peels. Outside this layer is a padding of cork cells.
There is also a type of tree which is wrapped in a thick shell made entirely of cork. The cork is composed of different cells, which prevent water and other materials from sifting into the plant. Industrial cork is “peeled” from the tree once every three to four-and-a-half years. Cork trees are found in southern Europe and northern Africa.
Question of the Month:
This month’s question was sent by Gladys, age 10, of Brooklyn, NY.
Dear Professor, Which is the largest known mammal in the world?
The giant blue whale, reaching 108 feet in length, is the largest known mammal in the world.