Why weather forecasts aren't always accurate?

Wind blowing on a woman.

You probably listen to a weather forecast every day.

Nearly everything that you do is affected by the weather.

Have you ever wondered how it is possible to predict something as changeable as the weather?

On the other hand, why is it that the weather forecaster is so often wrong?

In order to appreciate the weather forecaster’s task, we need to understand something about the nature of weather, and what causes it.

Above the earth’s surface, the atmosphere extends hundreds of miles into space.

But we are concerned here with only the bottom layer, some six to nine miles thick, called the “troposphere.”

This layer contains some five quadrillion tons of air, and it is within it that all the weather happens.

There are three primary properties of the atmosphere involved in the weather—temperature, pressure and humidity.


Temperature

Earth temperature.

The fundamental cause of all weather is the unequal heating of the atmosphere by the sun’s rays.

This comes about because the atmosphere itself is transparent and absorbs very little energy directly from sunlight.

The sun’s rays go through to the earth’s surface, where they are reflected or absorbed, in varying degrees.

Water reflects more light, and land, especially dark-colored earth, absorbs more.

If the surface absorbs a lot, it is warmed.

If it reflects a lot, it remains cooler.

The equatorial regions receive more heat because the sun’s rays hit vertically.

In the polar regions, they strike obliquely, so the heat energy in an equal “bundle” of rays is spread over a larger area.

Also, the snow cover at the poles reflects most of the sunlight.

Consequently, it is colder at the poles.

Temperature differences caused by this process, called “insolation,” put in motion a chain of consequences that brings about the great variety in our weather.

Pressure

Air pressure.

An important factor is changes in pressure.

Since air at a higher temperature is less dense than the cooler air over another area, it rises.

This movement, in turn, generates differences in pressure between different areas.

A barometer, which measures the weight of atmosphere above it, will show a lower pressure under a rising column of warm air, which displaces the cooler, relatively more dense air above it.

On the other hand, a descending column of cool air will cause higher pressure below it.

The pressure difference at the surface causes a wind to blow from the region of higher pressure toward that of lower pressure.

It is similar to what happens when an inflated balloon is opened at one end.

The high-pressure air inside rushes out into the surrounding area of lower pressure.

The greater the pressure difference, the stronger the wind.

This principle operates on a global scale.

The global movements of air masses in different directions generate turbulent motions where the main streams brush against each other.

There is a additional effects from topography—the irregular outlines of continents and the complex patterns of mountains and plains, deserts and forests.

Humidity

Water vapor.

As air masses move across the surface of the earth, they pick up water.

Most of this is vapor from oceans, but some comes from moist earth.

Since warm air has greater capacity for moisture, air masses drawn toward low-pressure areas have relatively higher humidity.

The fact that water vapor weighs less than an equivalent volume of dry air further contributes to the lightness of columns of warm air rising in low-pressure areas.

What happens when humid air rises?

Pressure on it decreases, it expands and cools.

When the temperature falls to the level where the air becomes saturated, water begins to condense in droplets or ice crystals, forming clouds.

From these, rain or snow may fall.

The air, thus dried, descends in high-pressure areas, bringing clear weather.

The Weather Chart Meteorologists note the air’s varying properties of temperature, pressure and humidity.

At each weather station there are instruments to measure all of these.

A weather forecaster also studies wind direction and speed, the nature of clouds, visibility, whether it is or has been raining or snowing, and how much.

These data are organized for comparison with readings at other locations.

To facilitate this, all weather stations have a fixed hour by Greenwich mean time for gathering the needed information.

The observer must take into account that barometric pressure decreases with altitude under constant weather conditions.

In fact, the difference even at an altitude of one thousand feet is greater than that caused by changes in weather.

So a correction is applied to the reading at each station, to put all the readings on a common basis, as if taken at sea level.

With the help of such detailed information from weather stations over a wide area, a meteorologist plots a chart in a special “language” created by the World Meteorological Organization.

In this language information appears as numbers instead of words, making possible its transmission between ships at sea and land stations in various countries without need of translation.

Weather charts are then drawn with irregular curving lines called “isobars” that connect places reporting the same pressure.

Some of these lines form closed curves around regions that are thus identified as high- or low-pressure areas or, for short, “highs” and “lows.”

This gives the weather forecaster a good picture of the weather as it was at the time of the observations.

The Weather Forecast However, discerning what the weather is at a given moment is one thing; telling what it will be tomorrow or several days hence is quite another.

This requires examining a number of charts drawn up over a period of time.

Since each chart is like a photograph that pinpoints the weather at a given moment, by arranging several charts in order the weather forecaster views a “motion picture” of atmospheric movements.

Based on the most recent shifts of the highs and lows, one marks out their probable position for tomorrow.

Thus one can get a good idea of how the weather will change in the immediate future.

In view of today’s sophisticated equipment and scientific know-how, why are weather forecasts often wrong?

Why are meteorologists at times unable to foresee devastating storms that cause vast damage to property and loss of lives?

It is important to realize that your weather forecaster can only observe what is happening and tell us what he believes will happen next, but he cannot control weather conditions.

We cannot expect, in the nature of a  weather forecaster's task pinpoint accuracy.

For instance, he may predict showers in a given area.

But these are often local manifestations.

One locality might enjoy a heavy rain, and another, only a few miles away, might remain perfectly dry.

And there are other unpredictable factors.

Just as differing currents exist at various depths of the sea, so too the atmosphere at varying altitudes has different winds and air masses that influence one another.

Charts of higher altitudes contain fewer details, making it difficult to know in advance the effect of these more remote conditions on our weather.

When developing the forecast, the meteorologist must ask himself questions such as:

Will this low-pressure center continue at the same speed tomorrow?

Or might it slow down, or turn aside?

Is there any indication that the disturbance is weakening and might disappear?

Will the approach of the “low” to a stationary “high” interfere with it?

Which will probably prevail?

Far from being simply a matter of guesswork, however, weather forecasting is an art that involves detailed knowledge and skill.

Your weather forecaster can indeed help you to plan activities in advance, but he cannot guarantee what the weather will be.

And now you know why.

There are so many factors beyond the weather forecaster's control.

Read more…

How to protect your children from accidents?

A mother first-aids her child after a bicycle accident.

Daily, thousands of children worldwide meet with accidents that make a call to a doctor or a hospital necessary.

Each year, 1 out of every 8 children receives medical treatment after an accident.

Hence, if you are a parent, there is a substantial chance that something similar could happen to your child.

It is not strange that children are often injured in a familiar environment, such as the home and its surroundings.

The type of injuries they incur change as they get older.

An infant can easily fall off its nursing table or choke on a piece of food or a small object that gets stuck in its throat.

Young children often fall when they climb about or get burned or poisoned when they touch or taste things within reach.

Children of school age often get injured in traffic accidents or when playing outdoors.

Many of these accidents are preventable.

With a little foresight and a knowledge of your child’s level of development, you can help prevent injuries or even fatal accidents.

Indoors

Children opening windows.

You cannot teach the one-year, two-year, or three-year-old to avoid dangers and then count on them remembering.

Hence, the responsibility for helping your child to avoid accidents rests on you as the parent—or on other adults with whom the child stays now and then.

To begin with, take a look around your home.

Use the checklist in the adjoining box.

Perhaps some safety devices are not available in all countries or are not available at a reasonable price.

Yet with a little ingenuity and imagination, you can probably think of solutions that will work in your particular circumstances.

For example, if you have loop-type handles on your kitchen drawers, you can lock them by slipping a stick through the handles.

A similar arrangement could also serve as a lock for the oven door.

Plastic bags are much less dangerous if you tie them in a knot when storing them.

Perhaps you can think of other simple ways to prevent accidents in and around the home and can share these with friends and acquaintances who have small children.

Outdoors

Mother with her child with safety gear on.

Check the areas where your child plays.

Most injuries to children over four years of age happen when they play outdoors.

They fall down and hurt themselves or perhaps fall off their bicycle.

The most common fatal outdoor accidents for children between the ages of three and seven are traffic accidents and drowning.

When you inspect playgrounds, check to see if the equipment is in good working condition so that the child will not be hurt when using it.

Are surfaces under swings, climbing frames, and similar equipment composed of soft material, like loose sand, so that the child will not hurt himself if he falls?

Are there pools of water or streams near your home?

Only a few inches of water is enough for a one- or two-year-old child to drown.

When a little child falls face down in a pool of water, it loses its sense of what is up and what is down.

The child simply cannot get back up again.

The most fundamental rule, therefore, is this: Never let a child between one and three years of age play alone outdoors without adult supervision.

If there is a quantity of water in the neighborhood, wait until the child is considerably older before allowing him to play outdoors without supervision.

In traffic

Children's crossing traffic sign.

The same is true if there is traffic around your home.

A preschooler can only take in tangible messages and concentrate on one thing at a time.

But traffic is full of abstract conceptions and double messages.

Do not let your child cross a street on his own before he is of school age.

Children are not considered mature enough to cycle alone in busy traffic until they are at least 12 years of age, according to experts.

Teach your child to use a safety helmet when cycling, riding, roller-skating, or tobogganing.

Head injuries are difficult to treat and can cause permanent damage—or even be fatal!

At one children’s clinic, 60 percent of those treated after bicycle accidents suffered injuries to the head and the face, but those using helmets suffered no severe head injuries.

Also, make sure your child is safe when traveling by car.

Many countries have laws that require small children to be buckled up in specially designed safety seats.

This has drastically reduced the rate of injuries and deaths among children involved in traffic accidents.

If safety seats are available where you live, using one could be good life insurance.

But make sure it is an approved model.

Note that seats for infants are different from those for children from about three years of age.

Safety in your home

Child safety at home.

• Medicines:

Keep them out of the child’s reach in a locked cupboard.

The same goes for nonprescription and natural medicines.

Also, ask overnight guests to keep their medicines secure.

• Household chemicals:


Store them out of the child’s reach in a lockable cupboard.

Keep them in their original containers so that they are clearly identified.

Keep strict watch over the products as you use them, and always put them away, even if you leave the room for only a moment.

Never leave residues of detergent in your dishwasher.

• Stove:

Always turn the handles of pans inward on the stove.

Attach a saucepan guard, if available.

Equip the stove with a tilt guard for safety should the child climb on the open oven door.

The oven door itself should be equipped with a locking device.

Could the child burn himself by touching the oven door? Then, attach a guard or a grating so that he cannot touch the hot door.

• Dangerous household utensils:

Knives, scissors, and dangerous appliances should be kept in cupboards or drawers with locks or catches or stored out of the child’s reach.

When you are using such utensils and temporarily put them aside, place them away from the edge of the table or counter, out of the child’s reach.

Matches and plastic bags are also dangerous items for small children.

• Stairs:

Fit gates, at least 30 inches [70-5 centimeters] high, at both ends of stairs.

• Windows and balcony doors:

Equip them with childproof safety catches or chains high up or some other safety device that prevents the child from opening them or squeezing through them when they are opened to air out the room.

• Bookshelves:

If the child likes to climb and hang on things, secure bookshelves and other tall furniture to the wall, to keep them from falling over.

• Power outlets and electric cords:

Outlets not in use must be equipped with some kind of lock.

Cords for table lamps and the like should be attached to the wall or to furniture so that the child cannot pull down the lamp and be struck by it. Otherwise, take such lamps away.

Never leave the electric iron on the ironing board, and do not let the cord hang down loose.

• Hot water:

If you can adjust the temperature of your hot water, you should put it down to about 120 degrees Fahrenheit [about 50 degrees Celsius] so that the child will not be scalded if he or she turns on the tap.

• Toys:

Discard toys with sharp edges or corners.

Throw away small toys or toys that can be pulled into small pieces, as they can choke the child if put into the mouth.

Eyes and noses on the child’s teddy bears should be securely fixed.

Teach older brothers and sisters to remove their small toys when the baby is on the floor.

• Candy and snacks:

Do not leave candy and snacks, such as peanuts or hard sweets, within reach. They could get stuck in a child’s throat.


In case of an accident 

A father carrying his injured child.

• Poisoning:

If the child has swallowed some toxic liquid, rinse its mouth thoroughly and give it one or two glasses of water or milk to drink.

Thereafter, call a doctor or a poison information center for advice.

If the child has got something corrosive in its eye, immediately rinse with plenty of water for at least ten minutes.

• Burns:

For minor burns, apply cold (not too cold) water on the injury for at least 20 minutes.

If the injury is bigger than the child’s palm or is located on the face, a joint, or the lower abdomen or genitals, you should take the child to an emergency room.

Deeper skin injuries must always be treated by a doctor.

• Choking:

If something has got stuck in the child’s windpipe, it is most urgent that you get the object out quickly.

One effective method you might resort to is the Heimlich maneuver.

If you are not familiar with it, contact your doctor in order to get more information about this method, or attend a child-accident or first-aid course where this method is taught.

Read more…

Best ways to protect your skin from the sun

Sun skin protection.

Do you like to spend a vacation at the beach?

How about hiking in the mountains?

Then you are one of the millions who enjoy outdoor activities.

However, a word of caution: This often means added exposure to the sun.

Is there any danger in that?

If so, how can you protect yourself?

Bad effects of excessive exposure to sun

Picture of sunburn.

Your skin is the largest and one of the most visible organs in your body.

Your skin helps to protect your body against dehydration and to keep you warm.

It enables you to sense cold, heat, pain, and vibration, as well as rough or smooth surfaces.

Your skin also plays an important role in the production of vitamin D, which is essential to bone formation.

This production of vitamin D takes place with the help of sunlight.

However, there is increasing danger in excessive exposure of the skin to sunlight.

Solar radiation reaching the earth’s surface is composed of infrared and visible light, as well as ultraviolet light in the A and B ranges (UVA and UVB).

Fortunately, the atmosphere absorbs the cosmic rays, gamma rays, and X rays produced by the sun.

The atmosphere’s ozone layer effectively blocks ultraviolet C radiation (UVC) and filters out most of the UVA and UVB.

Unfortunately, this ozone layer is breaking down in places.

Many scientists blame certain refrigerants and aerosol propellants for the problem.

In any case, exposure to the sun is becoming ever more dangerous to your health.

Besides giving you a sunburn, ultraviolet rays can cause brown spots and progressive thickening and drying of your skin.

Ultraviolet can also weaken your skin’s elastic fibers, resulting in premature aging, including those dreaded wrinkles.

Worse yet, excessive ultraviolet exposure can interfere with your body’s immune system and may lead to the development of lesions and skin cancer.

As if this were not enough, damaged or diseased skin affects your appearance and may, in some cases, contribute to feelings of insecurity and even depression.

What can you do?

Picture of sunscreen and a hat.

Your skin needs day-to-day protection from the sun as much as it does during brief periods of intense exposure.

What can be done?

Besides wearing protective clothing and limiting the time you are exposed to the sun, you can follow the advice of experts who recommend the use of a sunscreen.

How can you choose an effective sunscreen?

Check the sun protection factor (SPF) indicated by the manufacturer.

The higher the number, the greater the protection.

People with light skin need sunscreens that have a higher SPF number than those with a darker complexion need.

A note of caution: The SPF refers only to a sunscreen’s protection against UVB radiation.

Therefore, give preference to broad-spectrum sunscreens, which also provide a measure of protection against UVA radiation.

Children, particularly those with fair skin, are especially sensitive to the sun.

Moreover, children often get more exposure to sunlight than adults do.

Taking steps to protect your child’s skin from the sun during his first 18 years of life can greatly reduce his chances of developing skin cancer.

Sunlight is indispensable to life on earth.

And who does not enjoy beautiful sunny weather?

But do not be fooled by popular images portraying bronzed skin as the epitome of beauty and youth!

Protect your health—protect your skin from excessive exposure to the sun.

Natural sun protection tips

A woman with a hat to protect her from sun rays.

 1. Protect yourself from the sun especially between 10:00 a.m. and 4:00 p.m., when the sun’s rays are strongest.

 2. Even on cloudy days, use a broad-spectrum sunscreen that protects against UVA and UVB rays and that has a sun protection factor of 15 or greater.

 3. Avoid tanning beds

 4. Wear protective, tightly woven clothing. Dark colors give more protection.

 5. Wear a hat with at least a four-inch brim and sunglasses with ultraviolet protective lenses.

 6. Stay in the shade whenever possible.

 7. Avoid reflective surfaces, such as water, sand, and snow, which reflect most of the sun’s damaging rays.

Read more…

How to lower your car fuel costs?

Picture about car expenses.

The number of families that own a car has steady increased over the last decade.

This means that gasoline is becoming a significant expense to more and more households

The annual gasoline expense of some households is quite high.

Certainly it is wonderful when the price of gasoline is cut.

Although the likelihood of this happening always is remote, there are ways of realizing benefits almost as dramatic as such a gasoline price cut.

How so?

By increasing the number of miles you are presently getting from a gallon of gas.

This can be done by practicing good driving habits and maintaining your car in proper running condition.

And perhaps by purchasing a more economical fuel.

Let us elaborate each of this fuel saving ways in more details.


1. Gas-saving driving habits

A driver driving a car.

After testing several advertised gas saving gadgets, all of which failed to improve gas mileage substantially, Popular Science reports:

Our conclusions are that the best ways to save gas and get more power from your car are to keep it tuned to factory [specifications] and improve your driving skills.”

Another automotive specialist assessed the motorist’s skill as the “most important single controllable factor in driving economy.”

But what are good, gas-saving driving habits?

The most important of all is easy, smooth acceleration.

Avoid tramping on the gas pedal.

Every time you do, an excess of gasoline is poured into the engine, much of which is expelled through the exhaust unused.

So economy driving means developing a feather foot.

This will eliminate such practices as jackrabbit getaways, darting about in traffic and nervous pumps on the gas pedal while waiting for a signal light to change.

Some expert drivers say that they imagine there is an egg between their foot and the gas pedal, and they always press gently so as not to break it.

This habit of smooth, easy acceleration can add up to ten more miles per gallon from your gasoline.

By developing the related habit of evenness in driving speed, you may make such remarkable gas savings a reality.

The biggest enemy of economy is the brake pedal.

Too many drivers forget to synchronize speed with traffic lights.

Expert drivers alertly watch traffic conditions, anticipating well in advance any necessary change of pace.

In this way they hold stops, starts and gear shifting to a minimum and maintain the steadiest possible speed.

The brakes are used only when necessary.

You can drive the same way.

Practice it.

The next time you get behind the wheel of a car concentrate on using a feather foot on the gas pedal, and determine not to use the brakes unnecessarily.

That will mean observing the red traffic light a block or two ahead and coasting toward it, instead of continuing to accelerate.

By the time you reach the light it may turn green, and you can continue without stopping.

Remember: Every time you use your brake it will take extra gas to build up speed again.

It is also important to avoid staying in the lower gears for extended periods.

On most cars, low gear at 20 mph. uses about 50 percent more gasoline than high gear at the same speed.

An “economy run” winner driving a standard shift car said that he usually up shifted at 11 or 12 mph. and again at 20 to 22 mph.

Cruising speed is important, too, the most economical being from about 35 to 50 mph.

To drive at 80 mph. nearly doubles the cost of gasoline from What it would cost to cover the same number of miles at 40 m.p.h.

So develop an economic style of driving and realize the benefits.

Not only will you stretch your gasoline, but you will find the relaxed and unhurried frame of mind most welcome.

It is safer and much more restful.

2. Proper maintenance

A man performing car maintenance.

Another way to save on money for gasoline is to have a regular spring and autumn engine tune-up.

Proper timing of the spark is vital to good gas mileage.

One faulty spark plug in a six-cylinder engine can waste as much as 16 percent of your gasoline.

Accurate adjustment of the idle speed screw to give a correct gasoline-air mixture will also save fuel.

A dirty air filter can add 10 percent to your gasoline bill, and a slow acting or stuck choke even more.

A good mechanic will check these and other matters when he tunes up your engine.

A simple thing that you can do to improve gas mileage is to keep the air in your tires up to specifications or slightly higher.

Under inflated tires are gas wasters.

3. Inexpensive gasoline

Putting fuel in a car.

Finally, you may be able to shave more dollars off your annual gasoline bill by purchasing a less expensive type.

Gasoline prices depend primarily on octane number.

This number indicates a gasoline’s ability to burn properly in an engine without knocking, which is a series of sharp pings or clicks when you accelerate or climb a hill.

After comparing regular and premium gasoline the above-mentioned Science Digest concluded:

There is little significant difference between regular and premium except for octane rating.”

Therefore, if your car can burn the less expensive, lower octane gasoline without knocking, it is a waste of money to use more expensive fuels.

Since today’s regular gas has as high an octane rating as the premium gas of several years ago, most older cars can use regular satisfactorily.

Even many newer cars, particularly smaller ones, can run efficiently on gasoline's with lower-octane numbers.

It may pay for you to experiment with lower-octane gasoline.

However, it is poor economy to use a gasoline that causes engine knock.

So there are several ways to stretch your gasoline.

It is conceivable that with a little care and thought your family may be able to save on gasoline each year.

Read more…