Yes. Washing your hands with soap and water cleans them of pathogens (bacteria and viruses) and chemicals that can cause disease. Hot water is not enough to clean your hands. Using soap adds to the time spent washing and breaks down the grease and dirt that carry most germs.
The most important times to wash your hands with soap and water are after you use the toilet or before handling food. When not washed with soap, hands that have been in contact with human or animal feces, bodily fluids like mucus, and contaminated foods or water can transport bacteria, viruses, and parasites to others. When done thoroughly and at least for 20 seconds, hand washing can prevent all types of illness and disease, skin infections, and eye infections.
“Dog days” are the hot, humid days of summer that usually take place in the Northern Hemisphere in July and August typically between July 3 and August 11. The days get their name from the dog star Sirius of the constellation Canis Major.
At this time of year, Sirius, the brightest visible star, rises in the east at the same time as the Sun in the northern hemisphere. Ancient Egyptians believed that the heat of this brilliant star added to the Sun’s heat to create this hot weather and they blamed the star for everything from withering droughts to sickness.
Absolutely. Being bitten by a plant-eating dinosaur such as Brachiosaurus, with its 52 chisel-like teeth, would certainly hurt! The bite of a Parasaurolophus, with its interlocking rows of teeth, might take off your fingers. In the Iguanodon, numerous sharp teeth were set in rows in the upper and lower jaws, and at steep angles to each other.
When the teeth were pressed together, the upper jaw was forced outward, creating a grinding motion between the teeth and its meal of crushed plant tissue.
A cobweb is an old, abandoned spider web that has collected dirt and dust. Sometimes the cobwebs you see in ceiling crevices and along floorboards are several draglines that spiders no longer use.
The common house spider—which feeds on many insects daily—often abandons webs that do not yield prey, and then constructs new ones until it finds a productive site. It’s best to sweep these old cobwebs away, and let your house spiders spin new webs, preferably outdoors!
As a matter of fact, yes! Researchers believe that regular contact with pets can reduce levels of stress and reduce blood pressure (the force of blood pushing against the walls of the arteries as the heart pumps out blood).
Pets offer stability, comfort, security, affection, and intimacy. Owning a dog also provides a great opportunity to get exercise and fresh air, since it will need to go for a walk every day.
America’s founders did debate a bit as to whether or not to force children to attend schools, and they decided to leave such decisions to individual families and local and state governments. The words “education” and “school” do not appear in any of our founding documents, such as the Declaration of Independence, the Constitution, or the Bill of Rights.
Some of our most famous inventors, writers, and politicians were self-taught, learning through mentoring or apprenticeships, conversation, and reading. In 1850, Massachusetts became the first state to institute a compulsory schooling law.
The first primitive plants appeared on land about 470 million years ago. But these plants did not look like the lush greenery we see in the world today. Rather, they were rootless patches of thin, leaflike plants called liverwarts, so named because some species look like green livers. Liverwarts used a specialized filament (called a rhizoid) to absorb water and stick to rocks.
Fossils reveal that the first true plants to colonize land appeared about 420 million years ago. These plants included flowerless mosses, horsetails, and ferns. They reproduced by throwing out spores, or minute organisms that carried the genetic blueprint for the plant. The ferns eventually bore seeds, but not until about 345 million years ago. Plants with roots, stems, and leaves (called vascular plants) evolved about 408 million years ago.
The Nobel Prize is the most famous international science award. Three science prizes, for chemistry, physics, and physiology or medicine, are awarded every year to people who have made significant contributions to these fields. The prize was created by the Swedish chemist and industrialist Alfred Nobel, who made a fortune from his invention of dynamite and left much of his money to fund the prize. Since 1901, the Nobel Prize has been honoring men and women from all parts of the world for their discoveries and inventions in these areas, as well as in the fields of literature and peace.
Some famous scientists and inventors who have been awarded the prize include Ivan Pavlov (in 1904), Albert Einstein (1921), and Linus Pauling (1954). Eleven women, from a total of 500 scientists, have been awarded a Nobel Prize in the sciences from 1901 to 2008. Among them, Marie Curie is the only person ever to have twice received a Nobel Prize in the sciences, each time in a different field of specialization: in Physics, in 1903, and in Chemistry, in 1911.
The word “toadstool” dates to the Middle Ages when it was associated with the toad, Which was thought to be poisonous. Toadstools, with their stool-like shape, are really mushrooms that are poisonous or inedible.
For example, the bright red “fly agaric” toadstool’s juice was once used to make a remedy for killing bugs. It is a very poisonous mushroom that still lives today and should be avoided.
Unlike the fragrant blossoms that attract bees, carrion flowers simulate the odor of a rotting animal carcass and attract carrion beetles and different types of flies, including blowflies, flesh flies, and midges. The stapelia flower, which is shaped like a starfish and grows in Africa, has fine hairs around its petals, perhaps to imitate the appearance of a small dead animal. When the bloom opens it gives off a rotting smell, imitating dead animal meat.
The smell attracts flies, which collect pollen before they fly away. Some carrion flowers, such as the European and Brazilian Dutchman’s pipe, lure insects into dark openings that lead to the foul-smelling interior where they become trapped. When the flower “releases” the insect, it is coated with fresh pollen to be taken to a different plant. The lantern stinkhorn, a fungus that releases a feces-like odor, attracts green bottle flies to spread its spores.