Everyone with children has kissed a small bruise or cut to make it better. This comes from one of our earliest medical procedures for the treatment of snakebite. Noticing that a victim could be saved if the venom was sucked out through the point of entry, early doctors soon began treating all infectious abrasions by putting their lips to the wound and sucking out the poison.
Medicine moved on, but the belief that a kiss can make it all better still lingers.
No. Very large finite numbers are not the same as infinite numbers. Infinite numbers are defined as being unbounded, or without boundaries or limits. Any number that can be reached by counting or by representation of a number followed by billions of zeros is a finite number.
The expression “frog in your throat” doesn’t come from sounding like a frog because you have a cold or sore throat. It originates from an actual Middle Ages medical treatment for a throat infection.
Doctors believed that if a live frog was placed head-first into a patient’s mouth the animal would inhale the cause of the hoarseness into its own body. Thankfully, the practice is long gone, but the expression “frog in your throat” lives on.
Beginning in the Middle Ages, Boxing Day was known as St. Stephen’s Day in honour of the first Christian martyr. Although unknown in the United States, Boxing Day is still observed in Britain, Canada, New Zealand, and Australia.
It’s called “Boxing Day” because on the day after Christmas, the well-off boxed up gifts to give to their servants and tradespeople, while the churches opened their charity boxes to the poor.
On a clear, dark night in your backyard, you can see about 2,000 or so stars in the sky, a small fraction of the 100,000 or so stars that make up our galaxy. They seem to twinkle, or change their brightness. In reality, most of the stars are shining with a steady light. The movement of air (sometimes called turbulence) in the atmosphere of Earth causes the starlight to get slightly bent as it travels from the distant star through the atmosphere down to the ground.
This means that some of the light reaches us directly and some gets bent slightly away. To the human eye, this makes the star seem to twinkle.
The combine harvester saves the farmers time and labor. Before modern machinery, harvesting crops was a painstaking process. Gathering and removing mature plants from the field had to be done by hand. Farm workers used sharp-bladed, long-handled scythes and curved sickles to cut down cereal crops like wheat. Even the fastest reaper could only clear about a third of an acre a day. Because rain could ruin harvested wheat, workers called sheaf-makers quickly tied it into bundles, so that it could be safely stored if the weather turned stormy. During the long winter months farm workers used jointed wooden tools called flails to thresh or beat the dried wheat in order to separate its edible grain seeds from its stalks.
But in 1786 a machine that threshed wheat by rubbing it between rollers was invented, replacing human threshers. And around 1840 a reaping machine—whose revolving wheel pressed grain stalks against a sharp blade that cut them down— replaced human harvesters. Today, farm machines called combine harvesters do this work in much the same way. These machines are very efficient and combine all three jobs of cutting, collecting, and threshing a crop. A single combine harvester can process five acres of wheat in less than an hour!
Since flowers possess both male and female parts, some flowers can fertilize themselves— or fertilize another flower on the same plant—which is called self-pollination. Or the ovules of one flower may be fertilized by the pollen of a different flowering plant of the same species, a method called cross-pollination.
The wind, water, insects, and other animals help to carry pollen from one flower to another. Crosspollination usually produces a better plant: the offspring of cross-pollination possesses the genetic traits of two parents, which may give it new characteristics that will help it survive in an always-changing environment. Cross-pollination is so desirable, in fact, that many flowering plants have developed different ways to keep selfpollination from happening. In the flowers of a spiderwort plant, for example, the stamens are ready to release pollen grains before the pistils are ready to accept them, so the pollen has to travel to other spiderwort plants in search of a ripe pistil.
Muscles are attached to bones by tendons, the longest and strongest of which is called the Achilles tendon in your heel. This thick band of tissue attaches the muscles of the calf to the heel bone and is the key to the foot’s ability to flex.
The Achilles tendon allows you to push off of your foot when walking or running. In ancient Greek myth, the hero Achilles died from a wound to his heel, so the popular expression “Achilles heel” often refers to a physical weakness or limitation.
Dinosaurs probably communicated both vocally and visually. Large meat eaters like Tyrannosaurus rex, with its loud roar, or a Triceratops shaking his head, would have made its intentions very clear. The chambered head crests on some dinosaurs such as Corythosaurus and Parasaurolophus might have been used to amplify grunts or bellows. Mating and courtship behavior and territory fights probably involved both vocal and visual communication. Scientists believe that the sounds created by dinosaurs like Parasaurolophus were so individual that each had a slightly different tone. They also believe that these dinosaurs had different calls, ranging from low rumbles to high-pitched notes, which they used for different situations.
During colonial times the U.S. Navy used the oak tree’s hard wood to build its ships. The U.S.S. Constitution received its nickname, “Old Ironsides,” during the War of 1812 because its live oak hull was so tough that British war ships’ cannonballs lit erally bounced off it. Because the Constitution was built before shipbuilders learned to bend or steam wood into shape, the live oak’s long, arching branches were used as braces to connect the ship’s hull to its deck floors. Throughout the years, oak wood has been used as lumber, railroad ties, fenceposts, veneer, and fuel wood. Today it is manufactured into flooring, furniture, and crates.