The air inside the tube increases in volume when heated up. As sufficient space for the expansion of the air is not available because the tube is already highly pumped, it may result in bursting of the tyre.
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.
Frogs are able to make their croaking noises because they have simple vocal cords that have two slits in the bottom of the mouth. These slits open into what is called a vocal pouch. When air passes from the lungs through the vocal cords, a sound is produced. The inflating and deflating vocal pouch makes the sound louder or quieter.
That sound changes depending on the kind of frog there are as many different kinds of croaks as there are frogs! Frogs croak for the same reasons that many animals make noises: to track down and then select a mate, and to protect their territory from other male frogs.
Euclid’s Elements is a series of 13 geometry and mathematics books written by the Greek mathematician Euclid in Alexandria about 300 B.C.E. It is a collection of definitions, postulates (axioms), theorems, and mathematical proofs of the propositions. The 13 books cover Euclidean geometry and the ancient Greek version of elementary number theory. Along with the Greek mathematician Autolycus’s On the Moving Sphere, the Elements is one of the oldest Greek mathematical treatises to have survived, and is the world’s oldest continuously used math textbook.
Historians do not know a lot about Euclid’s life, but his work has proven important to the development of logic and modern science. Most of the theorems in the Elements were not discovered by Euclid himself, but were the work of earlier Greek mathematicians such as Pythagoras, Hippocrates of Chios, Theaetetus of Athens, and Eudoxus of Cnidos. However, Euclid is credited with arranging these theorems in a logical manner.
Without the Sun, life on Earth would not exist. The planet would be a frozen dark ball, drifting in space. The Sun provides light, heat, and energy, which stirs up the atmosphere to create winds and rain. With it, plants grow, and animals and humans eat.
However, the Sun’s heat output changes over time, which affects our daily lives, the climate, and our satellite communications.
In medieval times, during the last feast of the Christmas week, knights of the realm were required to place their hands on a peacock and vow to continue living up to their pledge of chivalry. This was known as the knight’s “peacock vow.” The New Year’s custom of resolving to live a better life originated with the Babylonians, who promised the gods that they would return all borrowed farm and cooking tools and pay off personal debts.
The story of Cinderella was passed along orally for centuries before it was written down by Charles Perrault in 1697. While doing so he mistook the word vair, meaning ermine, for the word verre, meaning glass.
By the time he realized his mistake, the story had become too popular to change, and so instead of an ermine slipper, Cinderella wore glass.
An earthquake is a great shaking of Earth’s surface. It is caused by the cracking and shifting of the plates of rock that make up the planet’s layered crust. As shifting plates suddenly slide past one another, vibrations in the form of waves are released. These shock waves travel through Earth, gradually weakening as they move farther from the spot (or spots) where the quake began, which is called the epicenter. Regions located near faults (places where cracks in Earth’s crust are known to exist), are particularly vulnerable to earthquakes.
Earthquakes vary in size and intensity. They may last a few seconds or continue for a few minutes. They may cause no damage, or they can result in widespread destruction and the deaths of thousands of people. Earthquake vibrations can be so violent that they collapse bridges and buildings, destroy highways, cause landslides, and lead to flooding if they occur in shallow water near a coast.
It bends because it is made of two metals that are joined together, something called a bimetal switch. One metal (usually brass) expands quickly when heated, while the other expands much more slowly. This difference causes the switch to bend toward the low-expansion metal.
Bimetal switches are used in other appliances that switch electricity on and off to keep their temperatures even, like irons and refrigerators. The thermostat that regulates the temperature of your home by turning your furnace and air conditioner on and off also uses a bimetal switch.
Because animals are unpredictable and because schools have rules, it is never okay to bring animals out in public without the permission of both a parent and teacher. Even if you have permission, these creatures—such as snakes, rabbits, hamsters, gerbils, lizards, frogs, and other small critters—should be contained in their habitats and handled very carefully. Sometimes in public animals are outside of their natural habitats because they play a role in helping humans.
Guide dogs (also called seeing-eye dogs) help the blind or visually impaired move around cities and neighborhoods. These dogs are trained to behave properly on public transportation, in restaurants, in stores, and in any other place their masters go. Other times people carry their dogs and cats in pet carriers to the vet, to the park, or on shopping trips. However, they must have the store’s permission to enter, since many businesses (like restaurants and supermarkets) do not allow pets or require them to be contained and/or on leashes.