Knowledge N Fact4u

How do geologists use carbon dating to find the age of rocks ? •Geologists do not use carbon-based radiometric dating to determine the age of rocks.  •Carbon dating only works for objects that are younger than about 50,000 years, and most rocks of interest are older than that. •Carbon dating is used by archeologists to date trees, plants, and animal remains; as well as human artifacts made from wood and leather; because these items are generally younger than 50,000 years. •Carbon is found in different forms in the environment – mainly in the stable form of carbon-12 and the unstable form of carbon-14.  •Over time, carbon-14 decays radioactively and turns into nitrogen. •A living organism takes in both carbon-12 and carbon-14 from the environment in the same relative proportion that they existed naturally.  •Once the organism dies, it stops replenishing its carbon supply, and the total carbon-14 content in the organism slowly disappears.  •Scientists can determine how long ag

How much water can a camel store in its hump ? •Camels do not store water in their humps. Instead, camels use the humps to store energy-rich fat deposits.  •Many animals, including humans, use body fat as an energy storage. •Unique to a camel, however, is the fact that it stores the fat in a hump up on top instead of around the belly or limbs.  •It does this to stay cool. Fat has a natural tendency to insulate heat, acting like a blanket to bodies that are covered in fat.  •Being a hot-climate animal, a camel would waste energy trying to cool down if its fat were wrapped around its body. •Instead, by placing the fat in a hump that is out of the way, the camel can stay as cool as possible while still having an energy reserve.  •Think of it like a tourist from northern Siberia with a coat stuffed full of snacks just stepping off the plane in the Sahara Desert. What does he immediately do? He takes off his coat and slings it over his shoulder. He still wants to lug around his c

Why doesn't   a   laptop emit radiation ? •Your laptop computer does emit radiation. In fact, your laptop emits several different kinds of radiation: •400 to 800 THz electromagnetic radiation. This is the visible light given off by the laptop's screen that makes it possible for you to see what the computer is displaying. Yes, ordinary visible light is a form of radiation. •10 to 100 THz electromagnetic radiation. This is the infrared radiation given off by all parts of the laptop due to their temperature, through the everyday process of thermal emission. •5 GHz or 2.4 GHz electromagnetic radiation. These are the radio waves given off by the WIFI antenna in the laptop, which are used to connect to a wireless network. •2.4 GHz electromagnetic radiation. These are the radio waves given off by the Bluetooth antenna in the laptop, which are used to connect wirelessly to peripheral devices such as a cordless mouse. •Low frequency electromagnetic radiation. These are the ra

How do trees give earth all its oxygen ? •All of earth's oxygen does not come from trees.  •Rather, the atmospheric oxygen that we depend on as humans comes predominantly from the ocean.  •According to a study, about 70% of the oxygen in the atmosphere comes from marine plants and plant-like organisms. •These ocean-living plants release molecular oxygen as a waste product of photosynthesis (as do most plants). •In photosynthesis, plants capture sunlight and use its energy to split carbon dioxide and water, making sugar for itself and releasing oxygen as a by-product. •The dominance of ocean life as earth's top oxygen producer makes sense when you consider that the majority of the earth is covered with ocean. •Of the different types of marine life providing oxygen, the dominant class is phytoplankton.  •Phytoplankton are microscopic photosynthesizing organisms that live in water.  •Phytoplankton includes cyanobacteria, green algae, diatoms, and dinoflagellates.  •Althou

Clouds are just water vapor , so why do they move ? •Clouds are not water vapor. Water vapor is the gas state of H 2 O and is invisible.  •The air around you on a humid summer day is chock full of water vapor, but you don't see any of it.  •On the other hand, there is very little water vapor in the air during the cold of winter, yet you can easily make clouds with your breath.  •Clouds are collections of liquid water droplets or ice that are small enough to float.  •When the water vapor in the air gets cold enough, it condenses back into liquid in the forms of droplets.  •But the condensation is not automatic. It takes a bit of matter – a condensation nucleus – in order to jump start the process. Dust, salt, and ice in the air do the trick by providing a surface for the water to condense on to.  •Clouds are white because the water droplets making the cloud are the right size to scatter light resonantly according to Mie scattering.  •Mie scattering does not depend on wavele

How do magnets heal ? •Magnets have no healing properties. Magnetic Resonance Imaging (MRI) employs very strong magnetic fields, far stronger than a household magnet can produce, and yet MRI's have no direct effect on the health of the patient (an MRI may have an indirect effect as a diagnostic tool). •The iron in our blood is in far too low of a concentration to be affected by the weak magnetic fields of household magnets.  •Furthermore, the iron atoms in our blood are bound in heme molecules. The chemical bonds that hold the iron atom in the heme molecule interfere with the state of its electrons, causing the iron atom to lose its usual ferromagnetic properties. •The lack of healing properties for magnets has been established multiple times through controlled experiments. •For instance, M.S. Cepeda and colleagues found that static magnetic fields had no effect on pain levels. •A study performed by M.H. Pittler reviewing multiple experiments also confirmed the in

Why is plastic not used in home construction ? •Plastic materials are used in several ways in home construction. Plastic has useful properties such as water resistance, corrosion resistance, electrical insulation, and durability. •Here we are using the common meaning of the word "plastic": a synthetic moldable solid. Among the uses of plastic in home construction are: •Sewage pipes. These are increasingly being made out of plastic such as PVC instead of metal because PVC is cheap, corrosive resistant, light, and somewhat flexible. •Water supply lines. These are increasingly being made out of plastic such as PEX because PEX is cheap, strong, and flexible. The relatively high flexibility of PEX leads to better water flow and quicker installation. •Fuel supply lines. •Electrical conduits. These are channels that carry various electrical wires. •Insulating coating on electrical wires. •Housewarp. This is the weather barrier that is placed just behind the

Why are stars not blurred even though the earth is moving ? •Stars are blurred when viewed from earth. We just don't notice it much with our naked eyes because of the high temporal and low spatial resolution of the human visual system. •Take a glow stick, sparkler, or flashlight and spin it very quickly in the dark. You don't see an individual object anymore, but see instead a circular blur of light. •The reason for this is that the spin rate is faster than the rate at which our eyes can discern distinct images.  •The distinct images of the object get smeared together in a process known as motion blur.  •So why don't the stars look like spinning glow sticks? The rotation of the earth does cause the stars to spin in the sky, but the spinning is much slower. •Whereas it takes the stars one day to trace out a circular path in the sky, it takes tenths of a second for the glow stick to spin in a circle.  •Our eyes can mostly keep up with the motion of the stars because

Why do car tires protect you from lightning strikes ? •Car tires do not protect you from lightning strikes. Although the rubber in a tire acts as an insulator at low voltages, the voltage in a lighting bolt is far too high to be stopped by tires or air.  •No matter how thick your tires are, they don't stop lightning, according to scientists. •A study states that inside a car can be a safe place to wait out a lighting storm, but it's not because any materials are blocking the lightning. •Rather, if the car is struck by lightning, its metal frame redirects the electrical current around the sides of the car and into the ground without touching the interior contents.  •The ability of a hollow conducting object to protect its interior from electrical fields and currents is one of the fundamental principles of electromagnetics.  •Such an object is called a Faraday cage. For this reason, riding around in a convertible, on a motorbike or on a bicycle during a lightning storm

How do tractor beams work ? •Up until recently, tractor beams (beams of light that tow objects) existed only in the world of science fiction. •While large-scale tractor beams that can tow space ships are still machines of the future, microscopic tractor beams are here today.  •The idea at first seams to defy physics. Shoot light at an object and the light's momentum should push the object away from the light source according to the law of conservation of momentum; not pull it closer like a tractor dragging its cargo. •But what if you managed to create a situation where upon striking the object, the light gains forward momentum instead of losing it.  •In that case, the law of conservation of momentum tells us that the object will lose momentum in the forward direction, even to the point of going backwards, towards the light source. •So there is a way to make a tractor beam without violating any physics, if you can get the light to gain forward momentum upon interacting with the

Why is lead used in pencils even though lead is poisonous ? •The core of a pencil does not contain lead and never has. Pencils contain a form of solid carbon known as graphite.  •According to a study, the graphite pencil was first developed and popularized in the 1600's.  •The first users of graphite simply dug this mineral out of the hills and discovered it could be sawed into sticks and used as an excellent writing tool.  •During the 1600's, no one knew the chemical nature of this material, as chemistry itself was still in its infancy. •Since this writing material behaved similar to metallic lead, but had a darker color, people began calling it "black lead".  •Eventually, the name of the core of the pencil got shortened to "lead". In 1779, German chemist K. W. Scheele finally determined pencil lead to be composed of pure carbon.  •A decade later, A. G. Werner decided that this carbon material needed a new name and proposed the name "graphi

Why don't dark-skinned people get sunburns ? •Dark-skinned people do get sunburns. While it's true that the higher pigment levels that make certain people's skin look dark helps protect against sunlight, the pigments do not block 100% of the light. •The skin pigment melanin is produced by special skin cells called melanocytes to protect the body from the damaging effects of ultraviolet light.  •Higher levels of melanin means less sunburn and less skin cancer. •But even the darkest-skinned person is not protected 100% from sunlight. •A study found that 13% of black women and 9% of black men reported getting at least one sunburn in the past year.  •Furthermore, 38% of Hispanic women and 32% of Hispanic men reported getting at least one sunburn in the past year.  •For comparison purposes, the average value across all ethnicities and genders was 50.1%. While dark-skinned people definitely get fewer sunburns, they still get them.  •When a dark-skinned person gets a sunbur

Why does chocolate cause acne ? •Chocolate does not cause acne. Acne is caused by overactive sebaceous glands.  •Sebaceous glands are microscopic glands connected to the hair follicles.  •Their job is to secrete skin oil (sebum), which travels up the shaft of the hair and out onto the skin in order to waterproof the body.  •If the glands secrete too much skin oil, the channel along the hair's shaft becomes clogged.  •As a result, a buildup of skin oil and dead cells occurs in the glands and the hair follicle.  •This stagnant, clogged mass just below the skin's surface becomes infected with bacteria and turns into a pimple.  •Sebaceous glands accelerate their secretions in response to high levels of sex hormones, such as present during puberty.  •The causes of acne are therefore: 1) elevated sex hormones, 2) sebaceous glands that are overly sensitive to sex hormones, and 3) the presence of bacteria that take advantage of the situation.

Find out how these versatile plugand-play devices can store data Similar in nature to a conventional hard drive, a fl ash drive is a very convenient device capable of not only storing data, but also transferring it quickly between computers and digital devices. A form of solid-state storage (electronic, with no moving parts), fl ash drives are both robust and small enough to fit in your pocket and yet can hold vast quantities of data depending on how great their storage capacity. Flash memory is a type of EEPROM (Electrically Erasable Programmable Read-Only Memory) stored as small blocks. The chunks of data stored using fl ash memory can be erased and re-programmed electronically, making it a quick, effective way of transferring files. When you insert the fl ash drive into the computer’s USB port, the computer automatically detects the device. It then acts like an external hard drive, allowing you to immediately begin storing and retrieving data. The internal workings of a fl ash drive

Only a few years ago, seeing in 3-D meant peering through a pair of red-and-blue glasses, or trying not to go cross-eyed in front of a page of fuzzy dots. It was great at the time, but 3-D technology has moved on. Scientists know more about how our vision works than ever before, and our computers are more powerful than ever before -- most of us have sophisticated components in our computer that are dedicated to producing realistic graphics. Put those two things together, and you'll see how 3-D graphics have really begun to take off. Most computer users are familiar with 3-D games. Back in the '90s, computer enthusiasts were stunned by the game Castle Wolfenstein 3D, which took place in a maze-like castle. It may have been constructed from blocky tiles, but the castle existed in three dimensions -- you could move forward and backward, or hold down the appropriate key and see your viewpoint spin through 360 degrees. Back then, it was revolutionary and quite amazing. Nowaday