Main->Readings->5th Grade "Stretches"
Here's all those weird, astounding, important, and useless facts I share in 5th grade science class. You can read them in order or click on the topics below.
Most cells are microscopic, a word that comes from the Greek words mikros, meaning "small," and skopion, meaning "to look at," so the word "microscopic" means that something is so small it can only be seen with a microscope.
How small is that? Well, in order to measure cells you need to use microns, not inches or feet. A micron (the symbol is µ, and it's generally known as a micrometer these days) is a millionth of a meter. To put it another way, there are 1,000 microns in a millimeter, and ten millimeters in a centimeter, and your little finger is about a centimeter wide, so you could cover 10,000 microns with your little finger. A red blood cell (the stuff your blood is made of) is 5 microns wide.
So . . . How many red blood cells could you fit across your little finger?
Fungi include such things as mushrooms, molds, mildews, rusts, smuts, and yeasts.
Without fungi, dead wood would not decompose very well, lawns wouldn't grow, we wouldn't have many antibiotics, and a mushroom pizza would be an imaginary object. Not only that, you'd have to hold your sandwich fillings in your fingers because you wouldn't have yeast bread. A tuna salad sandwich would be a horrifying thing.
On the other hand, without fungi, there wouldn't be as many infections and my laundry wouldn't smell so awful when I forget to take it out of the washer overnight.
To make a spore print, take a fresh mushroom, cut its cap off, and put it on a sheet of white paper. Let it sit overnight. You should be able to see a deposit of spore dust on the paper the next day.
People who study fungi are called mycologists.
hyphae (hí - fee) plural: the threads that form the body of a fungus (mycelium (my - sée - lee - um))
mycorrhizae (my - koh - rý - zee) plural: a beneficial combination between a fungus and a living plant root
symbiosis (sim - by - óh - sis): a partnership formed between two living organisms.
The disease called "malaria" is caused by a protist, plasmodium. It starts by growing in the liver and then moves into the red blood cells, and causes fever and chills. It is spread by mosquitos. Yuck.
You aren't going to get malaria by being bitten by a mosquito in this country. Probably.
The first person to describe protists was Antoni van Leeuwenhoek, in 1676. He called them "animalcules."
I don't care what your encyclopedia says, Antoni van Leeuwenhoek didn't invent the microscope. He just made really good ones.
Some scientists think viruses, which are not made from cells, actually did come from cells to begin with. They think the nucleic acids (stuff in the nucleus of the cell) somehow changed and "escaped." Do you think viruses are alive or not?
The first fossils, from 3.5 billion years ago, are of things that look like bacteria. For more than half of Earth's existence the bacteria were the main form of life.
Some bacteria can survive below-freezing temperatures for years. Others can grow in boiling hot springs. Bacteria are even known to live in hot acid and in rock. They're EVERYWHERE.
Bacteria and blue-green algae are prokaryotes - prokaryotes are single-celled organisms without a nucleus. Eukaryotes are different. Eukaryotes include protists and the cells of many-celled organisms such as animals, plants, and fungi which do have a nucleus.
Deoxyribonucleic acid (DNA) inside the cells of every organism carries all the information needed to make a copy of that organism.
Sponges are the most primitive many-celled animals there are. They don't have tissues or organs. Most sponges are both male and female at once. If you use a natural sponge in the bathtub, you're washing with the animal's skeleton!
Echinoderms include sea stars, sand dollars, and sea urchins. Things that eat them are seagulls, fish, sea otters, asteriods, gastropods, crustaceans, and would you believe, humans.
People who study roundworms are called nematologists. The most popular nematode these days is a little tiny worm called c. elegans. It's popular because it's very small and simple and the scientists know what most of its DNA does. I personally like the name c. elegans (even though the "c" stands for Caenorhabditis) and think it would make a great name for a kid.
There is a bug I sometimes find under the bushes around the Haverford School in the summer. It is very small and grayish in color, and when it's disturbed it rolls itself into a ball for protection. Some people call these animals woodlice, but we generally call them pillbugs, and they're crustaceans--like crabs and lobsters--not insects.
Sponges are the most primitive form of many-celled life. They've been around for over 700 million years.
Sponges have skeletons made up of tiny needles or spicules. If you wash with a natural sponge, you're actually washing with its skeleton. There are four kinds of sponge skeletons: bony, glass, spongin, and a mixture kind (Calcarea, Hexactenellida, Demospongiae, and Sclerospongiae). Don't try to take a bath with a glass sponge!
If you put a living sponge in a blender and blend it (without damaging the cells), the sponge can put itself back together again.
Some sponges can build up pressure and squirt water long distances so they don't re-use the same old water.
Stinging-cell animals can be polyps or medusae, or both at different times. Polyps attach themselves to rocks and medusas swim around. Sometimes a stinging-cell animal will be a polyp and have babies which are medusae, and then the medusa will have babies which are polyps. It must be strange having a parent that looks like a completely different animal . . . or it would be strange if stinging-celled animals had brains to think about the idea!
Stinging cell animals include corals, hydras, jellyfish, the Portuguese man-of-war, and sea anemones.
Corals are polyps which attach themselves to other polyps, grow on the bodies of their ancestors, and make more corals by growing buds. They build entire island reefs this way.
Hydras are tiny animals (.25 to 2.5 cm) which move either by gliding or somersaulting. If you cut a hydra into large pieces it will grow into several hydras, but if you put small pieces close to each other they'll grow into one complete hydra.
The Portuguese man-of-war is a collection of cells (colony) more closely related to hydras than jellyfish. Its poison is 3/4 as strong as a cobra's venom.
A jellyfish has no head, no anus, and no brain. It does have a gut. The thing we think of as the jellyfish is only the medusa form. Medusa babies are usually polyps, which live on the sea bottom and reproduce to make more medusas. Jellyfish swim by contracting muscles around their rims. They are 99% water.
The most venomous jellyfish is the Australian sea wasp, (also known as the box jellyfish). It has enough poison to kill 60 humans.
Flatworms take in food and let out waste through the same body opening.
There are about 5,000 species of tapeworm, and every one of them is a parasite. Planarians are not parasites. They are carnivores.
Roundworm parasites include hookworms, which can cause elephantiasis; trichina worms, which cause trichinosis, and whipworms, which can live in the human intestine.
There are enormous numbers of nematodes in the surface layer of our soil; this is actually a good thing, since they enrich the soil. Remember that: some roundworms are good.
To get trichinosis, you eat meat (usually pork) that has larvae of the trichina worm in it. Your digestive juices help the larvae get going. The larvae grow up and mate, and the females burrow into the intestine and make new larvae. The new larvae enter the bloodstream, go into the muscles, and form cysts. Trichinosis can damage your heart, make you blind, and occasionally kill you. Urk.
You can prevent trichinosis by cooking pork thoroughly. Thank goodness.
You get hookworm from walking barefoot on ground that is contaminated with hookworm eggs. I am not going to go into the details of the hookworm too, and I'm not gonna talk about elephantiasis. Enough is enough.
Some mollusks (the word comes from the Latin mollus, "soft.") are clams, oysters, snails, slugs, octopi, and squid.
The plural of octopus is commonly "octopuses," but a
reader (Chris Doherty) tells me the correct and scientific plural of octopus,
according to Eric Partridge (author of the clarifying work on vocabulary 'Usage
and
Abusage') is not octopuses or octopi, but octopodes. At any rate, it is NOT
"octopi."
Octopuses have eyes that are very much like those of humans, even though mollusks and vertebrates are not closely related.
Octopuses (NOT octopi) and squid are "cephalopods," which means "head foot," and their arms come from the area around their mouths.
The Atlantic giant squid (Architeuthis dux) has larger eyes than any other animal. A squid found in Canada in 1878 had eyes with an diameter of about 50 cm. (20 in.). The giant squid is the largest invertebrate in the world. They often measure over 18 m. (59 ft.) in length.
Snails, are gastropods (which means "stomach foot") and they glide along using wave-like contractions of the bottom of their foot. Also they leave slime. Slugs are related to snails but they don't have shells.
A snail's tongue is like a ribbon covered with teeth (denticles).
The gut of a segmented worm is a straight tube, and the segmented worm has a simple nervous system.
Earthworms and leeches are basically hermaphrodites: that means each one is both male and female.
You probably already know that earthworms pass soil through their bodies, making the soil richer. . .
But did you know that leeches have a chemical called hirudin that keeps blood from coagulating (so it will keep flowing)? Leeches can be 5 mm to 46 cm long, and they eat about three times their weight in blood in one feeding and then live on it for months. Doctors sometimes use leeches to suck out patients' blood when it doesn't drain from injuries.
The arms of echinoderms radiate from the mouth area, which faces down. If they have an anus, it's on top.
Sea stars have a simple nervous system but no brain. However, they can touch, smell, taste, and respond to light.
Very few animals eat sea stars. They don't taste good and they aren't nourishing. Sea stars, on the other hand, are carnivores and eat meat. For many sea stars, if you cut them into pieces, each piece can grow a new sea star. The sea star class is called Asteroidea.
Insects are the largest class in the animal world. There are at least 800,000 species (and many more undiscovered), and they live everywhere from the polar regions to the tropics. Only some insects are bugs (true bugs are a specific kind of insect).
Insects all have three pairs of legs growing from the thorax. A caterpillar has three pairs, too. His other legs are just little bumps growing from the back segments, they aren't real legs.
"Arthropod" means "jointed foot." Scientists think arthropods evolved from the segmented worms.
The millipedes (Diplopoda) don't have a thousand feet, and the centipedes (Chilopoda) don't have a hundred. Millipedes can have from 24 to 106, and centipedes can have the same number. They are very different, though: millipedes feed on decaying plant life and may have stink glands, while centipedes are carnovores and have poison.
Spiders can only eat liquid food, so they digest their prey outside the body and then suck the fluid.
Some crustaceans switch sex as they get older.
Scientists prefer properties that can be measured. The science of weights and measures is called metrology. Many measures are based on the human body. The inch comes from the width of a thumb. The foot (12 inches) is, of course, the length of a foot. This can be a problem if you're dealing with people of different sizes. Measures like this are also hard to multiply, divide, and convert. The United States still uses many of these old measures ("English customary units"), even though much of the rest of the world has changed to the metric system.
The metric system was started by the French in the 1790's. It's great because it works by multiplying by 10 and is easy to convert. It's incredibly reasonable. Scientists use it all over the world. Americans still haven't changed over completely, probably because somebody else thought of it first.
The word for changing over to the metric system is metrication.
The alchemists believed they could change "base metal" (such as lead) into gold. The word for that is transmutation.
The alchemist Paracelsus, in the 1500s, thought matter was made of salt, sulfur, and mercury.
Separating mixtures is a big part of the mining industry and the recycling industry. Making mixtures is essential to concrete and pottery. Most things around us--rocks, air, water, dirt, classrooms, people--are mixtures.
Solutions are a kind of mixture. A solution of a solid in a liquid, or a gas in a liquid, or a liquid in a liquid, is usually clear. Milk obviously isn't a solution, then, is it? It's a suspension. And if you drink homogenized milk, it's milk that has been mixed so energetically that it doesn't separate out into its parts. When I was a kid, milk wasn't homogenized. The cream in it rose to the top. You had to shake the bottle before you poured the milk out.
You may think matter is solid, but that's an illusion. Matter is made up of energy and empty space. This is no consolation when you fall off your bike, because it really hurts when the energy and empty space of two things - the pavement and your body - collide.
Niels Bohr suggested that the electrons traveled around the nucleus in orbits, like planets around the sun. The current theory is more that the electrons exist in probability clouds around the nucleus. The Heisenberg Uncertainty Theory says it is impossible to know both the location and the speed of an electron at the same time. It's not just hard, it's impossible. Can't be done.
Some elements have odd symbols. For instance, silver has the symbol Ag because its ancient Roman name was "argentum."
NaCl, NaHCO3, CH3COOH, and C12H22O11 are all common substances found in your home. What do you think they are?
Dihydrogen monoxide is a common element found in your home as well. For some reason, many people with web sites on the Internet like to post pages that talk about the "dangers of dihydrogen monoxide." See if you can figure out why this is funny. Hint: "di" means two in chemistry-speak, and "mon" means one, while "oxide" means oxygen is involved.
Here's a chemistry joke: Q: What common table tool can you make from the elements Potassium, Nickel and Iron? A: KNiFe. Get it? No? Oh, well.
Mendeleyev organized the Periodic Table because he was writing a textbook. He was writing a textbook because he couldn't find a good one to use for teaching his students, and decided to make his own.
Mendeleyev also worked on the liquefaction of gases; the expansion of liquids; a theory of solutions; a theory of the inorganic origin of petroleum; the chemistry of coal; Russian weights and measures; and the universal ether. The last theory (the uinversal ether) has been disproved. Many great scientists have worked hard on things that turn out not to be true.
The heaviest elements are man-made ones that only exist for short times in laboratories.
In 1997 the elements 104-109 were officially named after many years of arguing. They are: Rf, #104, Rutherfordium, Db, #105, Dubnium, Sg, #106, Seaborgium, Bh, #107, Bohrium, Hs, #108, Hassium, and Mt, #109, Meitnerium. As you might expect, they're all named after chemists.
Water, unlike most other substances, expands when it cools. Therefore, it gets less dense. Try filling a plastic container (with a tight lid) with water and putting it in the freezer overnight. Just try it. See what happens. Oh, yeah, and if you have a really good scale in the house, weigh the full container before and after. What happens? Does the weight change?
One of the biggest problems in medicine is trying to freeze donor organs so they can be used later in transplants. Because water expands when it cools, cells explode from the pressure of the liquids inside them, and ice crystals shred the organs from inside.
Yuck.
Luckily, medical science is making advances in this area.
Chemists describe chemical reactions with equations. The equation for rust is:
4Fe + 3O2 -> 2Fe2O3
An equation always has an equal number of atoms on each side of the arrow. See if you can figure it out. (By the way, although water helps the process along, it doesn't get involved.)
Newton's Laws of Motion:
1. Objects at rest will stay at rest and objects in motion will stay in motion in a straight line unless acted upon by an unbalanced force.
2. Force is equal to mass times acceleration. (F=ma)
3 For every action there is always an opposite and equal reaction.
Newton's First Law means that things don't start moving by themselves unless they're already moving. Once they start moving, they keep moving in a straight line unless something is pushing on them.
A rocket on the launch pad is balanced. The surface of the pad pushes the rocket up while gravity tries to pull it down, and it doesn't go anywhere. Without Newton's Laws, it would be a huge paperweight.
Newton's Third Law is what lets rockets move. The action is the pushing of gas out of the engine. The reaction is the movement of the rocket in the opposite direction. To enable a rocket to lift off from the launch pad, the action, or thrust, from the engine must be greater than the mass of the rocket.
The Second Law means that in order for rockets to get up into orbit, they have to shoot a large mass of gas out at high acceleration. If you shot out a little bit of gas at a slow speed, it wouldn't produce enough force to counteract gravity or the friction of air.
However, once the rocket is in free fall (or, if it's far enough away from the Earth's gravity), it only takes a little bit of force to make the rocket change direction because the forces of gravity and friction are no longer as important; the rocket engine only has to be enough to affect the rocket's momentum.
There were actually four Sputnik satellites. The third Sputnik satellite was launched on April 27, 1958, but it was destroyed 88 seconds after launch, and it wasn't given a number. The official Sputnik 3 took off on May 15, 1958; it was supposed to gather information about the Van Allen radiation belts but its tape recorder failed.
Sputnik 1 went over the United States twice before anybody in the U.S. even knew it existed.
NASA was created on the 29th of July, 1958, by President Dwight D. Eisenhower.
The Russians launched Gagarin's ship Vostok (as well as Sputnik, and all the later manned missions) from a site in Kazakhstan: Baikonur Cosmodrome. They named it after a town called Baikonur which is actually about 200 miles away, in order to mislead anyone who might want to spy on their space program or sabotage it.
Gagarin had a doll with him on his flight, to show weightlessness when it began floating in free fall. Thirty years later, on April 12, 1991, another cosmonaut, Musa Manarov, carried Gagarin's doll with him on the space station Mir.
Gagarin died on March 27, 1968, in an air crash, while preparing for Soyuz 3. What caused the crash? Was it bad weather, an unstable plane, or a near-collision with other jets that got too close? In spite of thorough investigations, nobody is sure.
The first human space flight of the 21st Century was February 11, 2000. Space Shuttle Endeavor lifted off with the crew of Commander Kevin Kregel, Pilot Dom Gorie, and Mission Specialists Janice Voss, Janet Kavandi, Gerhard Thiele and Mamoru Mohri to take care of the Shuttle Radar Topography Mission (basically that means they were mapping the whole world).
Because the Gemini missions each had a two-man crew, the Gemini Program was named "Gemini" after the constellation containing two stars, Castor and Pollux. Castor and Pollux were the names of twins from Greek myth.
Alexei Leonov, the first human to "spacewalk" outside in vacuum, was one of the first 20 people chosen to be cosmonauts. When he was finished with his spacewalk, his suit had expanded so much he couldn't fit back inside the capsule and had to let some air out. In 1969, when he was riding behind the Premier in a parade, he barely survived an attempt to assassinate Premier Brezhnev.
For some reason, all the interesting facts I came up with about manned flight to the Moon have to do with failures, endings, and second chances.
Apollo 1 wasn't really a flight, it was a disaster. It wasn't even a test-flight, it was a launchpad test. NASA named it Apollo 1 following the fire which killed astronauts White, Chaffee, and Grissom. There was no Apollo 2 or Apollo 3.
Alan Shepard was captain of the Apollo 14 mission in 1971. It was his first spaceflight mission since he was the first American in space in 1961, due to the inner-ear problem which grounded him.
The Apollo 17 mission in 1972 was the last manned spaceflight to the Moon. Nobody has been there since. Sometimes that makes me very sad.
Donald K. ("Deke") Slayton never made it to the Moon because of an irregular heartbeat. However, he was restored to flight status and went on a joint U.S./USSR Apollo-Soyuz mission in 1975.
The Russians sent a number of probes to the Moon from 1959 to 1976: first probe to impact the Moon, first flyby and image of the lunar farside, first soft landing, first lunar orbiter, and the first around-the Moon probe to return to Earth. However, due to political problems, the death of a major space scientist and an astronaut (Vladimir Komarov in 1967), and some unmanned flight accidents, the Soviets never landed a human being on the Moon.
Shuttles have included Columbia, Challenger, Discovery, Atlantis, and the newest one, Endeavor, all named after famous sea-going ships. The NASA people call them by their numbers (Discovery, for instance, is OV-103) and each mission of the shuttle has its own number (the first mission of the year 2000 was STS-99, Endeavor, which is OV-105). Are you confused yet?
In June of 1983, STS-7, Challenger, carried the first U.S. woman in space, Mission Specialist Sally Ride.
In August of 1983, STS-8, Challenger, carried the first African-American man in space, Mission Specialist Guion Bluford.
January 28, 1986, STS 51-L, Challenger, exploded in the air 73 seconds after lift-off, killing the crew, which included Christa McAuliffe, the first Teacher In Space. NASA didn't send up another mission until September 29, 1988.
In August of 1992, Mae Jemison became the first African-American woman in space on STS-47, Endeavor.
In July of 1999, STS-93, Columbia, was the first to be commanded by a woman, Eileen Collins.
My favorite space shuttle wasn't really designed to go into orbit. That was the Enterprise, named after the ships on the Star Trek television shows. In 1977, it was used as a test vehicle for the planned shuttle program, and it went through everything the space shuttles were going to do except go into orbit. It belongs to the Smithsonian Institution now.
About half of the bones in the human body are in the hands and feet.
When you were born, you had over 300 bones. When you're an adult, you have about 206. What happened? Did they fall off or something?
The longest bone in your body is the femur, or upper leg bone.
A few years ago, one of my students brought in a bone he had found at the beach. It was a long bone, very sturdy. I took it over and compared it with the Lower School skeleton, Mr. Bones. The bone was exactly the same size and shape as Mr. Bones' femur. My student took it home again and I've never heard what happened . How do you think the bone ended up at the beach? I sometimes think about that and wonder.
Most of your joints are free-moving joints called synovial joints. These allow you to bend, and jump, and stretch
Many people have a "growth spurt," (around 14 for boys and 12 for girls, but it can happen at many different points), when they put on height at a rate of 10 to 12 cm a year.
Bones tend to grow ahead of muscles, which means that muscles and tendons become tight and more easily strained when you're having a growth spurt.
Some of your joints are very complicated. For instance, part of the ankle joint moves like a hinge, moving up and down to allow you to stand on your toes and squat. The other part of the ankle joint allows your foot to rock side to side under your leg to enable you to move across uneven ground.
Medical experts generally agree that cracking your knuckles does not cause arthritis. You still shouldn't do it when you're around other people. It's one of many body functions that are annoying in public places.
You have more than 400 voluntary muscles and over 600 muscles altogether.
The cardiac muscle never stops working, your whole life. This is a good thing because its job is to push blood through your body.
Every muscle does only two things: it contracts (clenches and gets shorter) when it's being used and expands (unclenches and relaxes) when it's resting. Muscles don't push. They can only pull.
People who study the human body are called anatomists, and the study of the body is anatomy.
Your fingers are mostly powered by muscles in your palm--inside your fingers you mainly only have bones and tendons.
Newborn babies may sleep as much as 16 hours a day. Kids your age should be sleeping at least 10 hours a day.
However, kids your age sometimes have problems with nightmares, sleepwalking, and bedwetting, all of which are more common than you might think.
If you have problems getting to sleep, try to make your bedtime the same every night, don't do anything exciting right before bedtime, and don't drink anything with caffeine in it after about mid-afternoon.
On a regular day, your body loses two to three quarts of water (about the same amount that's in eight to 12 milk cartons from the cafeteria), and on a day that you're exercising and sweating hard, your body loses even more water. You get some water from the food you eat, but you also need to drink water too.
Even though our bodies need some fat to work properly, they don't need as much as most people eat. You get enough fat in your diet. Believe me, it's already there.
If you eat a balanced diet, you don't need sports drinks, energy bars, or much in the way of extra vitamins. It's all there in the food you already eat. But don't tell anybody. Think of all the people who would go out of business if people didn't listen to commercials and buy glitzy supplements.
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In 1848, Phineas Gage, a responsible hardworking railroad man, tamped some explosive down with his own custom-made inch-thick one-meter tamping rod, and set off an explosion. Propelled by the explosion, the rod shot in through his left cheek, destroyed his left eye, and came out the right front top of his skull. Though he fell down in convulsions, he soon stood up and spoke, and after being treated by a Dr. Harlow at a local hotel he eventually recovered his physical health. However, now he was a foul-mouthed liar who couldn't hold a job. He wasn't killed by the rod through his head, but something in his frontal lobe had been destroyed, something that helped him make good decisions.
The brain of an elephant weighs about 6 kg (13 lb). An adult human brain weighs about 1.4 kg (3 lb). This doesn't make the elephant smarter than a human. Brain size is related to body size.
There are about 100 billion neurons (nerve cells) in the human brain.
One nerve fiber (axon) in a giraffe neck is 15 feet long.
Humans have a left brain and a right brain inside their heads, connected by something called the corpus callosum. The right side of the body is controlled by the left brain, and the left side of the body is controlled by the right brain. In most people, the left brain takes care of mathematics, logic, and language and the right brain takes care of patterns, music, art, and creativity.
Reflexes usually have survival value. That means they help you stay alive. For instance, your eye's pupils get small when they're exposed to bright light so you don't get blinded when someone shines a light in your eye.
Reflexes happen faster than normal actions because they don't involve the brain.
They aren't the same thing as instincts. Instincts are automatic actions too, but they usually take a long time to happen. An example is birds migrating
People often talk about "reflexes" when they mean reaction time - that is, how fast you can do something intentionally. The kind of thing where someone shouts, "Think fast!" and throws something at you. It isn't the same thing as a real reflex. A real reflex is something like putting your hand on a hot stove by accident and yanking it off before you realize you're getting burned - the withdrawal reflex.
Some glands are the hypothalamus, pituitary, thyroid, parathyroid, pancreas, adrenals, and reproductive glands. The following useless facts are just a few of many I found:
You sweat from glands. You drool from glands. We call those exocrine glands. Other glands release their substances directly into the blood, and we call them endocrine glands.
A square inch of your skin may have as many as 625 sweat glands.
The thyroid gland needs the substance iodine to do its job. If you don't get enough iodine in your diet, you can get a goiter, a big swelling on your neck where the thyroid is. In the United States iodine is often added to our table salt, so you don't see goiters very often.
The pituitary gland at the base of the brain makes and releases about eight different hormones. If your pituitary is messed up, you can have all kinds of things wrong with you, including not growing properly. The pituitary is sometimes called the master gland because of that.
Did you know your body makes its own steroids? Steroids are natural products of the body. For instance, the adrenal glands on top of your kidneys, besides making the emergency-response hormone epinephrine, make about 30 steroids. There are already so many steroids in your body that taking more can cause all kinds of problems. Your body is already a humongous soup of chemicals.
Along with all the other things they do, the reproductive glands make the hormones testosterone and progesterone. People think only males have testosterone and only females have progesterone, but that's not true.
Hormones are truly weird chemicals. We're still finding things out about them constantly.
Some quick facts: According to the National Council on Alcoholism, 1 in 13 adults is an alcoholic or abuses alcohol. According to the U.S. Department of Health and Human Services 2000 survey, slightly less than 1 in 3 people over 12 use tobacco. About 1 in 15 people reported using illegal drugs in the previous month. Depending on where you look and how things were counted, these numbers can be different.
The word "drugs" is usually used to mean drugs that are bad for you. There are plenty of those. There are also drugs which are good for you, which are called "medicines" or "pharmaceuticals". How do you know which is which?
First of all, it's always a bad idea to take illegal drugs. But you knew that.
It isn't just the illegal drugs that are bad for you. Some of the legal ones can do you harm too, if you don't follow a doctor's advice. Even some safe ones are unsafe if you take too much.
Some surprisingly dangerous drugs are sold "over-the-counter" in drug stores. Some are sold in health food stores. In this country, as long as you don't call something a drug (for instance, if you call it an herb or a nutritional supplement) you can sell it without having to follow all the safety procedures required for drugs. So just because it's a "vitamin" or an "herb" doesn't mean it can't make you plenty sick.
Just so you know, Dr. Turner doesn't smoke, drink alcoholic beverages, or take any illegal drugs.
However, like many people, I drink coffee. Coffee contains caffeine, which is a drug. I also use an asthma inhaler containing a drug that helps me breathe, and when I overstress my muscles training too hard I take a drug called ibuprofen, which is an anti-inflammatory pain reliever like aspirin. I also take a daily vitamin, when I remember, and an antihistamine when my allergies act up.
However, I think that taking illegal drugs is a stupid idea, and that if you want to damage your brain cells it would be cheaper and simpler just to stand facing a brick wall and whack your head into it repeatedly. Though I don't recommend that, either.
Some humans also do something very peculiar: they abuse drugs. That means they take way too much and deliberately mess up their brains and bodies. Drug abuse isn't something that just happens to poor people, street people, or people in cities. It happens in nice places like the suburbs and the country, and it happens to rich people as well as poor people. Sometimes (not always), if someone is behaving very oddly, he or she may have a problem with drugs or alcohol.
Ice cubes shrink in the freezer because the H2O goes directly from a solid to a gas (it's called sublimation). Frost-free freezers have a constant breeze blowing through them, and the moving air makes the molecules on the outside of the cube get excited and move more quickly, going straight to water vapor. Unfortunately, you can't stick your head in the freezer and watch this happening, no matter how hot it is outside.
In order to find out if sunscreens work, scientists test them on the backs of people who have been selected for their pale, sensitive skin. They paint sunscreen on a patch of skin about the size of a playing card and blast the subjects with a "solar simulator" in a line of 5 small circles across the patch, each one a stronger zap than the previous one.
This page last modified May 6, 2003
Copyright 2002 Delia M. Turner, Ph.D.