Plant adaptations

Did you know that not all deserts are hot? Some deserts are extremely cold and they are called tundra deserts. Here is a video that shows how plants in different conditions adapt to the environment. Enjoy :)

More about plant adaptations in deserts

Desert Plant Adaptations
Habitats in Central Washington range from alpine and rainforest in the west, to dry ponderosa forests and shrub steppe to the east. A few plants can live in variety of conditions, and some are restricted to specific habitats.
The plants that grow in the arid eastern region near the Columbia River and the Columbia Basin have a number of traits which help them to be successful in the desert. In the photo to the left is Salvia dorrii and Artemisia tridentata in the Columbia Basin near Moses Coulee, Washington State. Two of the main adaptations of plants in arid environments is having an economical water management system, and maximizing the energy gain from the process of photosynthesis. Some plants, called xerophytes, have adapted their physical structure to suit the rigors such a harsh environment as the desert. 1/3 of the earth's land surface is desert, or about 10% of the total earth surface. Xero- means dry and -phyte means plant. These plants have adapted by having smaller leaves, grow compactly and close to the ground, and a non-porous covering on their leaves such as wax. Hair on the leaves of plants helps to reduce the evaporation of moisture from the surface of leaves by reflecting sunlight and inhibiting air movement. The process of photosynthesis requires both carbon dioxide and water to create energy for the plant. Water is usually absorbed through the roots, and carbon dioxide is absorbed through tiny pores in the plant called stomata. Through the stomata the plant is able to obtain carbon dioxide, but it also loses water by evaporation when the pores are open. Some plants cope with the water loss problem by having fewer stomata, or by having the stomata only open at night when it is cooler. All of these adaptations help to reduce evaporation and transpiration of water. Differences in cellular structure and function, as well as in the basic process of creating carbohydrates from water and carbon dioxide also help plants to survive in arid conditions. The common process of photosynthesis is called the C3 cycle because carbon is fixed by the plant into a three carbon compound (phosphoglyceric acid) in order to make carbohydrates. Another process of photosynthesis used by desert plants such as bunchgrass fixes the carbon into a four carbon compound (malate or aspartate acid). This C4 process, although not used by many plants, is more efficient in maximizing energy gain than normal photosynthesis.

Pseudoroegneria spicata- bluebunch wheatgrass.
Succulent plants such as stonecrop (Sedum spp.) and cactus can store water in the specialized tissues of plant cells called vacuoles. In some desert plants the cells, unlike in the ordinary varieties of cultivated plants, can also survive extreme dehydration then rehydrate when water is available with little or no damage to the cells. It also helps desert plants to have spines or prickles to deter animals from eating the photosynthetic material it worked so hard to produce. Succulents especially need this protection because their cells are full of water that thirsty animals would love to eat. There also many chemicals that are produced by plants that deter herbivores. Other plants, called phreatophytes, have adapted root systems that are long enough to reach underground water sources. Phreato- means well and -phyte is plants. Tamarisk or salt-cedar is example of a phreatophyte. It is an invasive non-native plant, which can cause severe problems because it robs rivers and aquifers of water particularly in the Southwest US. Native examples of phreatophytes an extensive root system is the big sagebrush (Artemisia tridentata) and Ericamerica nauseosa, whose roots can grow up to 25 meters deep. Because big sagebrush is able to utilize underground water sources it can remain photosynthetic throughout the summer, and is one of the latest blooming of all plants in the Columbia Basin. Other plants cope with the extremes in temperature and rainfall by becoming dormant during the winter or droughts, and escaping difficult times all together. Annual plants, also called ephemerals, only grow for one growing season- from seed to flower to seed and grow only when conditions are at optimum. Some seeds can remain dormant for years and even decades, waiting to germinate when the conditions are favorable. Members of the Liliaceae- Lily family and others such as the genus Lomatium (Apiaceae family), store energy within their roots when they bloom in spring and set seed. The Lomatium macrocarpum or bigseed biscuitroot has 80% or more of the plants tissues are below the soil surface in the roots. This stored energy is enough to survive for most of the year in a dormant state. By late summer the upper parts of the plant and leaves dry out above the ground and the have already matured and blown away, leaving none of the plant's soft tissues exposed to heat and dryness of summer. By the middle of summer many plants in a desert environment are dormant, and show few signs of life. Another strategy of drought avoidance can be seen near any stream or wet area. Some plants only germinate and grow in riparian areas, forming the stark contrast in vegetation seen near any water source in arid regions.

Source: http://www.cwnp.org/adaptations.html

Adaptation to dry conditions

This is a plant which is able to survive in very dry conditions. Its sahpe is very different from that of plants found in wet places. Therefore, it is said to be adapted to suit its environment. Environment means surroundings. Adapt means to change so as to fit in with the surroundings.

Plants which are able to survive in dry conditions are called xerophytic. These usually undergo four main types of adaptation, all of them to help conserve water. Conserve means to use up as little as possible.
Take a look at the xerophytic plant. In this case, it is the famous cactus known for its spiky leaves. Did you know that the leaves are one of the most important adaptations of the cactus?

1. These leaves are thin, like spines, and curled round so that water losing pores (stomata) are on the inside, away from the sun and wind.
2. The roots spread out just under the surface of the soil. This is so that when the rain falls, it rarely soaks more than one metre deep. The roots spread out widely in this shallow layer to take in soil water quickly after a shower
3. Desert plants store water to conserve water. Roots and stems are some parts of the desert plants which are able to do so. A round shape can hold more than a long, thin shape so most desert stems have riunded, swollen shapes
4. Stems and leaves are designed to reduce water loss by evaporation. They have a waxy coating which keeps water in . The rounded shapes give desert plants snall surface area for their size compared with plants in wet areas. This means thet have less surface to lose water from, so they keep more water witthin them than plants in wetter lands.

Steps in science by R Bateman and P Lidstone Book 3

Chapter 2 page 14

Autotroph Humans

Here is the article Mrs Phua showed us in class. Enjoy! :) It is not ruled out that they will replace us at a new evolution stage People all around the world were storming supermarkets and grocery stores on Christmas and New Year's Eve. There was a small group of people, though, who did not even think about eating anything for Christmas. In fact, they do not think about food at all. Such people call themselves autothrophs – they do not eat at all. The term designates an organism that makes its own food. Autotrophs can go on hunger strikes for years and even decades. Irina Novozhilova, the president of the center for protection of animals' rights, expressed her opinion about phenomenal individuals, who can live without food and water. ”The idea to turn down food as it is appeared long ago. Russian philosophers, particularly Vernadsky, were thinking about a possibility for a human being to live on something non-material. Vernadsky was certain that man is an energetic creature that can nourish himself from the energy of space. Some people can prove it today that it is possible to live a normal life without physical food. ”All living beings on our planet can be divided into two categories – autotrophs and heterotrophs. The majority of plants constitute the first category – they receive energy from non-organic substances – sunshine or air – and process it during the photosynthesis. Humans and animals make the second category: they nourish themselves with other living beings. Therefore, the people, who can live on the solar and space power, are closer to plants than to other humans. There is a group of autotrophs in Moscow. They gather in the Konstantin Vasiliev Museum, where they share experience with others. If a woman breastfeeds her child until it turns seven years old, for example, a child will be able to become an autotroph already by eight – simply and painlessly. A mother neither drinks nor eats, but she has enough milk to feed the baby. There are such women in Moscow. I often interact with people, who reject food completely. At first they become vegans - they exclude all products of animalistic origin from their menu in other words. After that they gradually turn down the vegetal food too. When people stop eating physical food, they also stop consuming any kind of liquid. They drink nothing. ”I would not say that scanty nourishment exerts a negative influence on their state of health. They are rather vigorous and cheerful people. However, I would like to warn everyone that it is impossible to quit drinking water and eating food in a moment. It should be done slowly, step by step, with short-term temporary starvation. A lethal outcome would be inevitable otherwise. A person will be killed either with starvation or their own wastes. The 70-year-old Indian yogi Pralad Djani is one of the most renowned contemporary autotrophs. This man has not been eating or drinking anything for 62 years, since the age of six. Indian doctors examined and tested him: they placed the man in a special room, outfitted the room with surveillance cameras and sealed the bathroom. As it turned out, Pralad Djani's body was functioning absolutely normally. The body was producing urine, although it was being absorbed into the urinary bladder. The yogi said that he was receiving water from air. He also said that there was a tiny hole in the palate, from which drops of “heavenly” water penetrated into his mouth. ”Russia's most famous autotroph's name is Zinaida Baranova. The old lady from the city of Krasnodar is 67 years old. She was approaching her new existence very slowly. At first she gave up meat, then she turned vegetables down. She has been living without food and water for 4.5 years already. Scientists of the Bauman Institute examined her organism and were very surprised to find out that the woman's biological age corresponded to 20 years. Professor Spiridonov came to conclusion that the pensioner was a perfectly healthy lady; all her systems and organs, except for the stomach, were functioning normally. Indeed, she is a very energetic and bubbly person. She got rid of all diseases, even chronic ones. She said, however, that it was rather hard for her to get used to the new lifestyle. She was suffering from cramps, exhaustion, dry mouth, etc. There were moments, when she thought she was dying. The woman's health improved in 1.5 months. ”Doctors say that autotrophs make a fundamentally new type of self-sufficient human beings. It is not ruled out that they will replace us at a new evolution stage. Modern science has already confirmed the ability of a human being to maintain itself. Dietitians were recently saying that the B12 vitamin was naturally contained only in animal foods. Vegans, therefore, were supposed to die, since they could not receive the vitamin. However, doctors found out that the concentration of the B12 vitamin was fine with vegans. The situation became clear, when scientists discovered the synthesis process in the intestines. It became known that human beings could live on their own microflora. Medics have already discovered that the human intestines produce microorganisms that can synthesize amino acids.” http://english.pravda.ru/science/19/94/377/14815_autotroph.html

Cactus Juice

Health Benefits of Cacti

There is more to the cactus plant than just a prickly house ornament to collect and admire. Medical studies conducted reveal that cactus extract contains phytochemicals, the cancer-fighting nutrient found in most fruits and vegetables, and also nutrients that strengthen the immune system.

Cactuses are drought-resistant plants found mostly in hot and dry regions. Cactus fruits are considered by some as “nature’s most perfect food”, with a large percentage of water, sugar, and minerals contained in it’s soft and gel-like flesh. The fruit performs a laxative function, increasing the frequency and ease of bowel movements. The gel extract is also used in some parts of the world as a remedy for non-insulin dependent diabetics. An experiment conducted on non-insulin dependent patients showed a significant decrease in blood glucose and insulin levels in patients who were given a cactus-water solution. Cactus extract is also a food source of phytochemicals. It enhances and strengthens the immune system’s ability to resist infection.

Another experiment conducted on the wound-healing properties of cactus juice produced a positive effect. Clinical studies show that the opuntia cactus is effective in fighting chronic inflammation. Cactus juice prevents scar forming and inflamation of the wounded area. The results of the experiment also show that cactus improves circulation and wound healing substantially.

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Nopal cactus juice is made from this desert plant's brightly colored fruit. You can use prickly pear cactus fruit for inflammation found in many areas of the body.

• Muscle
• Gastrointestinal
• Cardiovascular
• Arterial
• Bone

The fruit of the Nopalea cactus contains high amounts of calcium, magnesium and vitamin C. This cactus fruit also contains the amino acid known as taurine, is rich in flavonoids and antioxidant proteins known as betalains.

Nopal cactus fruit is low in calories, as well as sodium. In addition, it does not contain any cholesterol or saturated fat.

Nopalea cactus fruit nectar is also high in soluble fiber. The kind that is effective in reducing cholesterol in the blood. The American Heart Association has conducted research to measure nopal cactus fruit's ability to control cholesterol levels.

Nopal Cactus Juice Health Benefits

The nopalea cactus can provide you with the following health benefits:

• Helps you to lose weight! It curbs your appetite and blocks your body's ability to absorb fat
• Lowers your blood pressure
• Lowers your cholesterol levels! It improves your HDL / LDL ratio
• Helps to cleanse your body of harmful toxins
• Lowers your blood sugar levels
• Improves your mental focus & clarity

Find out more on http://www.best-natural-health-supplements.com/nopalea.html

Sources:http://worldvillage.com/health-benefits-of-cacti

http://www.best-natural-health-supplements.com/nopalea.html

How do desert plants adapt to conditions in the desert?

How Plants Cope with the Desert Climate

*Highlighted points are the adaptations

Desert plants have developed three main adaptive strategies: succulence, drought tolerance and drought avoidance. Each of these is a different but effective suite of adaptations for prospering under conditions that would kill plants from other regions.

Succulence - What adaptations do they have to survive in the desert?

Succulent plants store water in fleshy leaves, stems or roots. All cacti are succulents, as are such non-cactus desert dwellers as agave, aloe, elephant trees, and many euphorbias. Several other adaptations are essential for the water storing habit to be effective.

A succulent must be able to absorb large quantities of water in short periods.Desert rains are often light and brief, and the soil dries rapidly under an intense sun. To cope with these conditions, nearly all succulents have extensive, shallow root systems. The roots of a saguaro extend horizontally about as far as the plant is tall but are rarely more than four inches (10 cm) deep. The water-absorbing roots are mostly within the upper half inch (1.3 cm).

Succulents must be able to maintain their water hoards in a desiccating environment and use it as efficiently as possible. The stems and leaves of most species have waxy cuticles that render them nearly waterproof when the stomates are closed. Water is further conserved by reduced surface areas; most succulents have few leaves (agaves), no leaves (most cacti), or leaves that a deciduous in dry seasons (elephant trees, ocotillos, boojums).

Many succulents, as well as semisucculents such as most yuccas, epiphytic orchids, and xerophytic bromeliads, possess a water-efficient variant of photosynthesis called CAM, an acronym for Crassulacean Acid Metabolism. CAM plants open their stomates for gas exchange at night and store carbon dioxide. By day, while the stomates are closed, photosynthesis is conducted using the stored carbon dioxide. Because of the lower temperatures and higher humidity at night, CAM plants lose one-tenth as much water per unit of carbohydrate synthesized as standard C3 plants.

Another valuable attribute of CAM plants is their capability for idling metabolism during droughts. When CAM plants become water-stressed, the stomates remain closed both day and night; gas exchange and water loss nearly cease. The plant, however, maintains a low level of metabolism in the still-moist tissues. Just as an idling engine can rev up to full speed more quickly than a cold one, an idling CAM plant can resume full growth in 24 to 48 hours after a rain. Therefore, succulents can take rapid advantage of ephemeral surface moisture.

Stored water in an arid environment requires protection from thirsty animals. Most succulent plants are spiny or toxic, often both. Some protect themselves by growing only in inaccessible locations. Still others rely on camouflage. Arizona night blooming cereus, for example, closely resembles the dry stems of the shrubs in which it grows.

Now we know why plants like the cactus that grow in the desert have swollen leaves and spiky leaves. It's all for a matter of survival!

Drought Tolerance
Drought tolerance (or drought dormancy) refers to a plant's ability to withstand desiccation without dying. Plants in this category often shed leaves during dry periods and enter a deep dormancy. Most water loss is from transpiration through leaf surfaces, so dropping leaves conserves water in the stems. Some plants that do not normally shed their leaves have resinous coatings that retard water loss (e.g., creosote bush).

The roots of drought tolerant shrubs and trees are extensive compared to those of plants in wetter climates, covering an area up to twice the diameter of the canopy. They exploit the soil at greater depth than the roots of succulents; sometimes they extend to extreme depths (e.g., mesquite). Most of a mesquite's roots, however, are within three feet (0.9 m) of the surface.

(I think these type of plants do have roots that are so deep in the ground to absorb more water)

Rooting depth controls opportunities for growth cycles. In contrast to the succulents' shallow-rooted strategy, a substantial rain is required to wet the deeper root zone of shrubs and trees. After a soaking rain has fallen, shrubs such as brittlebush and creosote take a few weeks to resume full growth from deep dormancy. The tradeoff between this strategy and that of succulents is that once the deeper soil is wetted by several rains it stays moist much longer than the surface layer, supporting several weeks of growth.

Succulents can absorb water only when the soil is nearly saturated. In contrast drought tolerant plants can absorb water from soil that is much drier. Similarly these plants can photosynthesize with low leaf moisture contents that would prove fatal to most plants.

Drought Avoidance
Annual plants escape unfavorable conditions by not existing. They mature in a single season, then die after channeling all of their life energy into producing seeds instead of reserving some for continued survival.

Most Sonoran Desert annuals will germinate only during a narrow window in the fall, after summer heat has waned and before winter cold arrives. During this window of opportunity there must be a soaking rain of at least one inch for most species. This combination of requirements is survival insurance: an inch of rain in the mild weather of fall will provide enough soil moisture that the germinating seeds will probably mature and produce seeds even if almost no more rain falls in that season. There is still further insurance: even under the best conditions not all of the seeds will germinate; some remain dormant. Although the mechanisms are not known, a percentage of any year's crop of desert lupine seeds will not germinate until they are ten years old.

Seedlings rapidly produce rosettes of leaves during the mild fall weather, remain flat against the ground as they grow more slowly through the winter, and bolt into flower in the spring. Since the plants are inconspicuous until they begin the spring bolt, many people mistakenly think that spring rains produce our wildflower displays.

Annuals are common only in communities that have dry seasons, where the spacing of perennial plants is determined by the rooting space required to obtain enough moisture to survive the driest years. In the occasional wetter years both open space and moisture are available to be exploited by a population of fast-growing annuals. The more arid the habitat, the greater the proportion of annual species. Half of the Sonoran Desert's flora is comprised of annual species. In the driest habitats up to 90% of the plants are annuals.

The desert environment may seem hostile, but this is purely an outsider's viewpoint. Adaptations enable indigenous plants and animals not merely to survive here, but to thrive most of the time.

Source: http://www.desertmuseum.org/programs/succulents_adaptation.php

An interesting video on sound

Sound

Sound is the energy produced when objects vibrate.

Sound...

• helps us communicate
• allows us to enjoy music
• use as a warning

Why do you think that glass can produce such a beautiful melody?

By touching the glass, we are making it vibrate, thus, sound is produced.

Generation of electricity

In a fuel power station what happens?

1. A fuel such as coal, oil or natural gas is burnt and heat is produced to boil the water in the boiler.

Chemical potential energy of the fuel-->Heat energy of the water

2. The heat energy turns water into steam at high pressure, which goes through the boiler and turns the turbines.

Potential energy and kinetic energy of steam-->kinetic energy of the turbines

3. The turbines are connected to a generator, which converts the kinetic energy of the turbine blades into electricity

kinetic energy of turbines-->Electricity

Electrical energy

electricity or electrical energy is the energy that results from the flow of charged particles

Electricity is a useful form of energy that can be transformed into many other forms of energy.

Learn more from this video:)

Light energy

Light enables us to see

things that are luminous can give out light energy. The sun is an important source of light energy in the day.

Why are we able to see objects like books even though they don't give off light?

This is because light from a light source, like the sun, reflects light off the and into our eyes.

Why do we feel cool when wearing white on a sunny day but feel hot when we wear black?

Have you ever wondered why roses are red and why violets are blue? This should give you the answers. Enjoy :)

Ever wondered how heat travels?

Watch this interesting clip!

heat energy

Heat is the energy that flows from a region of higher temperature to one at a lower temperature.

Work

Oops... sorry everyone. I should have posted this last time before moments.

Conditions for work to be done

1. There is a force acting on the object
2. The object moves
3. The movement of the object is in the direction of the force

kinetic energy

kinetic energy is the energy that a body has due to its motion. All moving objects have kinetic energy.

Example: A girl walking down the street

This video should tell you more! :)

potential energy

Potential energy is stored energy due to a body's position or condition.

This video demonstrates gravitational potential energy. Enjoy! :)

Gravitational potential energy

Gravitational potential energy is the energy an object has because of its position or location. The higher the object is from the ground, the more gravitational potential energy it has, thus, it has more potential to fall

Example: a chandelier hung on the ceiling possess gravitational potential energy

Chemical potential energy

Chemical potential energy is the energy stored in fuels such as petrol and food that can be released through chemical reactions.

Example: We need to eat food to store ourselves with chemical potential energy so that it can be transformed into other types of energy as we carry out different activities like running (converted into kinetic energy)

Elastic potential energy

Elastic potential energy is the energy an object has when it is stretched or compressed.

Example: a stretched rubber band possesses elastic potential energy

The three classes of levers

here are the 3 classes of levers!

Levers

"Give me a place to stand on and I will move the earth!"

moment of forces

Definition:
The moment of a force (or torque) is the product of the force and the perpendicular distance form the pivot to the line of action of the force.
Principle of moment:
When a body is in equilibrium, the sum of clockwise moments about a pivot is equal to the sum of anticlockwise moments about the same pivot.

Why the plane crashed

The videos are quite long so watch it if you have time. :)

Aircrash Investigation Introduction

Pressure

Pressure

Pressure is defined as force per unit area. It is usually more convenient to use pressure rather than force to describe the influences upon fluid behavior. The standard unit for pressure is the Pascal, which is a Newton per square meter.

For an object sitting on a surface, the force pressing on the surface is the weight of the object, but in different orientations it might have a different area in contact with the surface and therefore exert a different pressure.

There are many physical situations where pressure is the most important variable. If you are peeling an apple, then pressure is the key variable: if the knife is sharp, then the area of contact is small and you can peel with less force exerted on the blade. If you must get an injection, then pressure is the most important variable in getting the needle through your skin: it is better to have a sharp needle than a dull one since the smaller area of contact implies that less force is required to push the needle through the skin.

Source: http://hyperphysics.phy-astr.gsu.edu/hbase/press.html

A hovercraft--moves easily because it has less friction

A hovercraft is an amphibious vehicle that is supported by a cushion of slightly pressurized air and moves just above the surface, be it land or water. The compressed air serves as a cushion that eliminates almost all friction between the vehicle and the surface. Although often seen as a mysterious, even bizarre mode of transportation, it is conceptually quite simple.

To understand how hovercraft work, it is necessary to realize that the dynamics are more closely related to aircraft than to boats or automobiles. As a member of a family of air cushion vehicles (ACVs) or Ground Affect machines, which includes wing-in-ground-effect or ram wings, surface effect ships, sidewall hovercraft, and surface skimmers, hovercraft, are the amphibious members of the air cushion vehicle family. They are the most novel among vehicles that are supported by pressurized air. Refer to the illustration below as you read about exactly how hovercraft work.

Hovercraft float on a cushion of air that has been forced under the craft by a fan. This causes the craft to rise or lift. The amount of lift can range from 6" to 108" (152mm to 2,743mm) depending on the size of the hovercraft. The amount of total weight that a hovercraft can raise is equal to cushion pressure multiplied by the area of the hovercraft. To make the craft function more efficiently, it is necessary to limit the cushion air from escaping, so the air is contained by the use of what is called a hovercraft skirt. Fashioned from fabric, which allows a deep cushion or clearance of obstacles, hovercraft skirts vary in style ranging from bags to cells (jupes) to separate fingered sections called segments.

Once "lifted" or "on cushion", thrust must be created to move the hovercraft forward. With many craft, this is generated by a separate engine from the one used to create the lift, but with some, the same engine is used for both. As the diagram above indicates, the fan-generated air stream is split so that part of the air is directed under the hull for lift, while most of it is used for thrust.

Now that the hovercraft has lift and thrust, it must be steered safely. This is achieved through the use of a system of rudders behind the fan, controlled by handlebars up front. Steering can also be controlled by the use of body weight displacement ... a skill which is achieved after practice.

Source:http://www.discoverhover.org/abouthovercraft/works.htm

why are high heels bad

Wearing high heels can be fashionable and may make you feel taller, but at what price? High heels can cause foot problemswhile exacerbating foot problems that you already have. Leg andback pain also are common complaints from those who wear high heels.

Posture

A high heel shoe puts your foot in a plantarflexed (foot pointed downward) position, placing an increased amount of pressure on yourforefoot. This causes you to adjust the rest of your body to maintain your balance. The lower part of your body leans forward and to compensate for that, the upper part of your body must lean back to keep you balanced. This is not your body's normal standing position.

Gait

When walking, your foot is in a more fixed downward position (plantarflexed) therefore you are not able to push off the ground with as much force. This causes your hip flexor muscles in your legs to work harder to move and pull your body forward. Your knees also stay more bent (flexed) and forward, causing your knee muscles to work harder.

Balance

Walking in high heel shoes is like walking on a balance beam. It takes a lot of balance and just like teetering on a beam, there is not any support in a high heel shoe to catch you if you fall. High heel shoes cause your foot and ankle to move in a supinated (turned outward) position. This position puts you at risk for losing your balance and spraining your ankles.

Back

The normal s-curve shape of the back acts as a shock absorber, reducing reduce stress on the vertebrae. Wearing high heels causes lumbar (low-back) spine flattening and a posterior (backward) displacement of the head and thoracic (mid-back) spine. High heel shoes cause you to lean forward and the body's response to that is to decrease the forward curve of your lower back to help keep you in line. Poor alignment may lead to muscle overuse and back pain.

Hips

The hip flexor muscles are located on the upper front part of your thighs. They are forced to work much harder and longer to help you walk because your feet are held in a downward position (plantarflexed) and have reduced power to move your body forward. If your hip flexor muscles are chronically overused, the muscles can shorten and a contracture can occur. If a contracture occurs, this could lead to flattening of the lumbar (low-back) spine.

Knees

Knee osteoarthritis is twice as common in women. Some of that blame may be due to high heels. The knee stays flexed (bent) and the tibia (shin bone) turns inward (varus) when wearing high heels. This position puts a compressive force on the inside of the knee (medial), a common site of osteoarthritis. If you already have osteoarthritis, it is best to avoid wearing high heel shoes. High heels increase the distance from the floor to the knee and can result in increased knee torque which can also lead to osteoarthritis.

Ankles

High heels limit the motion and power of the ankle joint. The calf muscles (gastrocnemius & soleus) are shortened because of the heel height. The shortened muscles cause them to lose power when trying to push the foot off of the ground. The position of the ankle may also cause a shortening (contraction) of the achilles tendon. This can increase the pull of the achilles tendon where it attaches on the back of your heel bone (calcaneus) and may cause a condition called insertional achilles tendonitis.

Feet

With the foot in a downward position, there is significant increase in the pressure on the bottom (plantar) of the forefoot. The pressure increases as the height of the shoe heel increases. Wearing a 3 1/4 inch heel increases the pressure on the bottom of the forefoot by 76%. The increased pressure may lead to pain or foot deformities such as hammer toes, bunions, bunionettes (tailor's bunions) and neuromas. The downward foot position (plantarflexion) also causes the foot to be more supinated (turned to the outside). This change in foot position changes the line of pull of the achilles tendon and may cause a condition called Haglund's deformity (pump bump).

Skin and Toes

The narrow, pointed toe box that is often found in high heel shoes also causes damage such as corns, callouses and blisters. If you look at a baby or toddler's foot you will see that their toes are spread apart. If you look at an adult's foot, their toes are usually squished together. A lot of times this is due to the footwear that has been worn. If you trace the footbed (part of the shoe where you put your foot) of a high heel shoe on a sheet of paper, and then stand barefoot on that tracing, you will probably have quite a bit of overlap. Does it still seem like a good idea to put your foot inside that shoe?

Save Your Feet

If your car tires are out of alignment, you can only drive so many miles before you are at risk of blowing a tire. The same is true for your body. Things need to be in alignment. It is recommended that you only wear high heels for special occasions and even then only a heel height of 1 1/2 inches. Your feet and body will thank you - and you'll save money on trips to the podiatrist's office.

MagLev trains

A few countries are using powerful electromagnets to develop high-speed trains, called maglev trains. Maglev is short for magnetic levitation, which means that these trains will float over a guideway using the basic principles of magnets to replace the old steel wheel and track trains. In this article, you will learn how electromagnetic propulsion works, how three specific types of maglev trains work and where you can ride one of these trains.

Electromagnetic Suspension (EMS)

If you've ever played with magnets, you know that opposite poles attract and like poles repel each other. This is the basic principle behind electromagnetic propulsion. Electromagnets are similar to other magnets in that they attract metal objects, but the magnetic pull is temporary. You can easily create a small electromagnet yourself by connecting the ends of a copper wire to the positive and negative ends of an AA, C or D-cell battery. This creates a small magnetic field. If you disconnect either end of the wire from the battery, the magnetic field is taken away.

The magnetic field created in this wire-and-battery experiment is the simple idea behind a maglev train rail system. There are three components to this system:

• A large electrical power source
• Metal coils lining a guideway or track
• Large guidance magnets attached to the underside of the train

The big difference between a maglev train and a conventional train is that maglev trains do not have an engine -- at least not the kind of engine used to pull typical train cars along steel tracks. The engine for maglev trains is rather inconspicuous. Instead of using fossil fuels, the magnetic field created by the electrified coils in the guideway walls and the track combine to propel the train.

Photos courtesy Railway Technical Research Institute Above is an image of the guideway for the Yamanashi maglev test line in Japan.

The Maglev Track

The magnetized coil running along the track, called a guideway, repels the large magnets on the train's undercarriage, allowing the train to levitate between 0.39 and 3.93 inches (1 to 10 cm) above the guideway. Once the train is levitated, power is supplied to the coils within the guideway walls to create a unique system of magnetic fields that pull and push the train along the guideway. The electric current supplied to the coils in the guideway walls is constantly alternating to change the polarity of the magnetized coils. This change in polarity causes the magnetic field in front of the train to pull the vehicle forward, while the magnetic field behind the train adds more forward thrust.

Maglev trains float on a cushion of air, eliminating friction. This lack of friction and the trains' aerodynamic designs allow these trains to reach unprecedented ground transportation speeds of more than 310 mph(500 kph), or twice as fast as Amtrak's fastest commuter train. In comparison, a Boeing-777 commercial airplane used for long-range flights can reach a top speed of about 562 mph (905 kph). Developers say that maglev trains will eventually link cities that are up to 1,000 miles (1,609 km) apart. At 310 mph, you could travel from Paris to Rome in just over two hours.

Germany and Japan are both developing maglev train technology, and both are currently testing prototypes of their trains. (The German company "Transrapid International" also has a train in commercial use -- more about that in the next section.) Although based on similar concepts, the German and Japanese trains have distinct differences. In Germany, engineers have developed an electromagnetic suspension (EMS) system, called Transrapid. In this system, the bottom of the train wraps around a steel guideway. Electromagnets attached to the train's undercarriage are directed up toward the guideway, which levitates the train about 1/3 of an inch (1 cm) above the guideway and keeps the train levitated even when it's not moving. Other guidance magnets embedded in the train's body keep it stable during travel. Germany has demonstrated that the Transrapid maglev train can reach 300 mph with people onboard.

Electrodynamic Suspension (EDS)

Photo courtesy Railway Technical Research Institute Japan's MLX01 maglev train

Japanese engineers are developing a competing version of maglev trains that use an electrodynamic suspension(EDS) system, which is based on the repelling force of magnets. The key difference between Japanese and German maglev trains is that the Japanese trains use super-cooled, superconducting electromagnets. This kind of electromagnet can conduct electricity even after the power supply has been shut off. In the EMS system, which uses standard electromagnets, the coils only conduct electricity when a power supply is present. By chilling the coils at frigid temperatures, Japan's system saves energy. However, the cryogenic system uses to cool the coils can be expensive.

Another difference between the systems is that the Japanese trains levitate nearly 4 inches (10 cm) above the guideway. One potential drawback in using the EDS system is that maglev trains must roll on rubber tires until they reach a liftoff speed of about 62 mph (100 kph). Japanese engineers say the wheels are an advantage if a power failure caused a shutdown of the system. Germany's Transrapid train is equipped with an emergency battery power supply. Also, passengers with pacemakers would have to be shielded from the magnetic fields generated by the superconducting electromagnets.

Maglev Accidents On August 11, 2006, a maglev train compartment on the Transrapid Shanghai airport line caught fire. There were no injuries, and investigators believe that the fire was caused by an electrical problem. On September 22, 2006, a Transrapid test train in Emsland, Germany had 29 people aboard during a test run when it crashed into a repair car that had been accidentally left on the track. The train was going at least 120 mph (133 km) at the time. Most passengers were killed in the first fatal accident involving a maglev train.

The Inductrack is a newer type of EDS that uses permanent room-temperature magnets to produce the magnetic fields instead of powered electromagnets or cooled superconducting magnets. Inductrack uses a power source to accelerate the train only until begins to levitate. If the power fails, the train can slow down gradually and stop on its auxillary wheels.

The track is actually an array of electrically-shorted circuits containing insulated wire. In one design, these circuits are aligned like rungs in a ladder. As the train moves, a magnetic field the repels the magnets, causing the train to levitate.

There are two Inductrack designs: Inductrack I and Inductrack II. Inductrack I is designed for high speeds, while Inductrack II is suited for slow speeds. Inductrack trains could levitate higher with greater stability. As long as it's moving a few miles per hour, an Inductrack train will levitate nearly an inch (2.54 cm) above the track. A greater gap above the track means that the train would not require complex sensing systems to maintain stability.

Permanent magnets had not been used before because scientists thought that they would not create enough levitating force. The Inductrack design bypasses this problem by arranging the magnets in aHalbach array. The magnets are configured so that the intensity of the magnetic field concentrates above the array instead of below it. They are made from a newer material comprising a neodymium-iron-boron alloy, which generates a higher magnetic field. The Inductrack II design incorporates two Halbach arrays to generate a stronger magnetic field at lower speeds

Maglev Technology In Use

Image used under GNU Free Documentation License
A Transrapid train at the Emsland, Germany test facility.

While maglev transportation was first proposed more than a century ago, the first commercial maglev train made its test debut in Shanghai, China, in 2002 (click here to learn more), using the train developed by German companyTransrapid International. The same line made its first open-to-the-public commercial run about a year later in December of 2003. The Shanghai Transrapid line currently runs to and from the Longyang Road station at the city's center and Pudong airport. Traveling at an average speed of 267 mph (430 kmh), the 19 mile (30 km) journey takes less than 10 minutes on the maglev train as opposed to an hour-long taxi ride. China is building an extension of the Shanghai line that will run 99 miles (160 km) to Hangzhou. Construction is scheduled to begin in fall 2006 and should be completed by the 2010 Shanghai Expo. This line will be the first Maglev rail line to run between two cities.

Several other countries have plans to build their own maglev trains, but the Shanghai airport line remains the only commercial maglev line. U.S. cities from Los Angeles to Pittsburgh have had maglev line plans in the works, but the expense of building a maglev transportation system has been prohibitive. The administration at Old Dominion University in Virginia had hoped to have a super shuttle zipping students back and forth across campus starting back in the fall semester of 2002, but the train remains motionless while research continues. The American Maglev Company is building a prototype using similar technology in Georgia that it plans to finish by fall 2006.

Source:

http://science.howstuffworks.com/maglev-train.htm