This Weather for Kids course is designed for parents to begin teaching their children about the weather and how it affects their world. It is primarily intended as a fun learning experience for both parents and kids, but it has a secondary goal of creating the basis for a life-long interest in science and nature.
Whether this interest grows to the point of further studies and an eventual pursuit of a career or studies in a S.T.E.M. (Science, Technology, Engineering, and Math) field is not important at this point.
What is important is that kids and parents share a sense of discovery as they learn about the world around them.
Weather and Science should be part of the child’s curriculum in school. We feel that by sharing these topics outside of a school environment so the child will have greater enthusiasm towards their lessons.
What’s more, this enthusiasm will carry over into other subjects. Children who are raised in an environment where learning for its own sake is encouraged are more likely to have greater success throughout their education. Greater success in school is just the icing on the cake. There are more than seven billion people living on the planet, and every one of them feels the effect of weather.
Talking about the weather has always been one of mankind’s most common conversation topics. We all enjoy nice weather and complain when it is not, but if we understand the weather even a little bit, then frightening and dangerous conditions become less scary. If the child is less scared in a dangerous weather situation, she is more likely to make the correct decisions and stay safe.
Check out the first 5 Chapters of our Weather for Kids Course
The best way to know what the weather is doing is to step outside and feel it for yourself. Weather Measuring Instruments by themselves cannot tell us if it is a nice day, but they will measure the things that make the weather enjoyable or miserable. In this discussion, we will explore how both digital/electronic and traditional analog instruments function.
Calibration is an important concept to understand with any weather measuring instruments.
If an instrument is calibrated we know that whatever it is measuring will be the same as the measurements taken by other instruments. If the thermometer outside your window says the temperature is 72°F, then another thermometer in the same spot should read the same if both instruments are calibrated to the same standard.
This is very important if weather data is being shared over a weather station network like WeatherUnderground or the National Weather Service, but it is also reassuring to know that the instruments in your home weather station are accurate. Highest quality weather instruments are calibrated to NIST (National Institute of Standards and Technology) and the calibration can be tracked for the life of the instrument.
Temperature Gauges
Thermometers are probably the most familiar weather instruments. Many homes have a thermometer or two mounted outside, and it is not uncommon for public buildings to have a temperature display incorporated into their signs.
Thermometers measure temperature, of course, but they do not always tell the full story when it comes to “how hot is it today?”
Measuring comfort seems subjective, but heat index and wind chill can be very useful for understanding human performance as well as comfort. Air temperature is just one element of these measurements, but it is a very important one.
If you are looking for simple and reliable temperature gauge that also show the comfort check our top pick from ThermoPro TP50 . Any gauge from your local store will also do a decent work, however the accuracy depends form brand to brand and instrument to instrument.
ThermoPro TP50 – Temperature Gauge – also indicates comfort level
Liquid thermometers are traditionally the most common. They are traditionally referred to as mercury thermometers, even though real mercury is difficult to find due to its expense and the danger of accidental mercury poisoning.
Liquid thermometers take advantage of the fact that liquid expands at a known and measurable rate in response to temperature changes. The warmer the temperature, the higher the level of liquid in the thermometer tube and the level is compared to a scale built into the thermometer case, or sometimes etched into the tube itself.
The other common form of analog thermometer is the dial type. These work on the principle that different metals expand at different rates in response to temperature change. Strips of two different metals are bound together and then formed into a coil spring. As the temperature changes, the different expansion rates will force the coil to tighten or straighten. The coil is attached to a simple clockwork mechanism attached to a dial where we can read the temperature.
Digital temperature gauges include thermocouplesand thermistors. A thermocouple is similar to the bimetallic element of a dial thermometer, except that rather than turning a dial as a result of temperature changes, the two metals in the element create an electrical charge that changes according to temperature.
Thermistors are a type of electronic resistor made of metal oxides encased in epoxy or glass. As temperature changes, so do the electrical resistance of the device, which can be measured and displayed.
Wind Gauges
Wind direction and speed are measured by wind vanes and anemometers. Knowing the direction the wind is coming from is important in predicting the sort of weather it will bring with it.
Traditional wind vanes are a common sight commonly seen on barn-tops and chimneys. They are mounted on the highest spot available so as to read wind direction without interference.
They consist of a pointer and a flat vertical material mounted behind a pivot point. As the wind acts on the flat element, the pointer points in the direction the wind is coming from. When mounting a wind vane, especially an electronic one, it is important to use a compass to ensure the instrument is mounted in relation to true north.
Mechanical Anemometers are instruments that measure wind speed. They take their measurement by counting the rotations of the shaft over a period of time. Cup anemometers have a vertical shaft with three or four hemispherical cups mounted on arms perpendicular to the shaft. Three cup anemometers are considered more accurate because there is less interference.
Propeller or vane anemometers have horizontal shafts with a propeller mounted on the end. The propeller itself is intrinsically more accurate at sensing wind speed, but must be held directly into the wind, so the unit is often incorporated into a wind vane. The advantage of the cup type anemometer is that it will sense wind strength from any direction.
Kestrel 5500 one of the best Wind Meters on the market
Wind-chill is a measurement of relative comfort. Cold weather “feels” colder since moving air removes heat from a body faster than still air. There are charts and formulas for measuring wind chill at various temperatures and wind speeds, but most electronic weather stations which have an anemometer and a temperature gage will derive wind-chill from installed software.
Pressure Gauges
Atmospheric or barometric pressure measurements are helpful in predicting weather. Generally steady or rising pressure indicates fair weather while a falling pressure means a storm or foul weather is approaching.
Barometers are the instruments used to measure atmospheric pressure.
The earliest type of barometers were the liquid type. This instruments air made by drawing liquid up into a clear (glass) tube and sealing the top of the tube. The liquid is held in the tube by the vacuum created in the top portion. The open bottom is placed below the surface of an open reservoir. As air pressure increases, the liquid in the tube rises.
A more common mechanical barometer is the aneroid type. These operate by comparing pressure between the inside and outside of a sealed “can”. The can has a flexible top that will flex in or out as the outside pressure changes. A very simple aneroid barometer can be made at home by placing a rubber diaphragm over a jar.
Pull a piece of a balloon over the mouth of the jar and seal it with a rubber band.
Tape a long pencil to the diaphragm as a pointer.
As pressure drops, the diaphragm will swell out and the point of the pencil will point lower, and pressure rises the diaphragm will be forced inward and the pencil will point higher.
Electronic pressure readings used by most home weather stations (and some Smartphones) are taken by a piezoresistive strain gauge. These devices have the advantage of being extremely sensitive and accurate in a small size.
Humidity Indicators
Is a measurement of the amount of moisture in the air. At specific temperatures and pressures, air can only hold a certain amount of water vapor. Relative humidity measures the amount of water vapor present compared to the amount air at the local temperature can hold. When relative humidity is 100% the air is said to be saturated.
At high relative humidity levels, liquid water cannot evaporate, and when humidity passes 100% water vapor condenses into liquid. As the temperature falls, the air will reach its saturation point, also called the “dew point”.
Humans regulate their body temperature with the evaporation of sweat. As humidity increases, evaporation of the sweat on the skin is less effective. This is the basis for the “heat index”, which measures how hot it “feels” at different temperature and humidity levels. Human performance, health, and comfort can be compromised at high heat index levels.
Measuring humidity is done with an instrument called a hygrometer. One type of analog hygrometer is a psychrometer, which consists of two thermometers. One thermometer is kept dry while the other has a moist fabric over the bulb. A
s the moisture in the fabric evaporates it cools the thermometer relative to the dry temperature and comparing the two readings give relative humidity.
Electronic hygrometers are usually of the capacitance type. The sensor has a polymer layer which absorbs moisture from the surrounding air, which changes the device’s capacitance. Most electronic weather stations mount the temperature gauge and the humidity gage near each other and use software to calculate heat index and dew point.
Analog Rain Gauges are among the most simple of all weather instruments to understand. Rainfall is measured by the amount of participation to fall over a certain area. Thus, all a rain gauge needs is a straight walled vessel with an open top. It can be as simple as a tin can placed on level ground. The disadvantage to such a simple instrument is that the observer needs to check it personally on occasion, measure the amount of liquid inside, and then dump out the water.
Electronic rain gauges measure rainfall amounts using a self-emptying tipping bucket sensor. The device consists of a funnel which directs rainfall into the bucket assembly. The bucket is divided into two chambers on either side of a teeter-totter mechanism. As the upper chamber fills, the bucket tips and that chamber spills its contents while the next chamber fills.
Every time the bucket tips, an electric switch is closed, and rainfall is measured by counting the number of times the connection is made.
Q1: What is the functional difference between a thermocouple and a thermistor?
Q2: What is the advantage of a cup type anemometer over a propeller type?
Q3: The cup type anemometer can read wind speed regardless of wind direction.
Q4: What does a falling barometer generally indicate?
Q5: Falling barometric pressure usually indicates an approaching storm or foul weather.
Q6: How does a psychrometer measure relative humidity?
Q7: How is rainfall measured?
Answers:
A1: thermocouple measures the voltage generated by two dissimilar metals at different temperatures while a thermistor changes electrical resistance as temperature changes.
A2: The cup type anemometer can read wind speed regardless of wind direction.
A3: Falling barometric pressure usually indicates an approaching storm or foul weather.
A4: The psychrometer measures the difference between a wet-bulb and a dry-bulb thermometer. As greater evaporation will lower the wet-bulb temperature, there will be less temperature difference at high humidity levels.
A5: The amount of rain falling over a specific area.
In this section, we present some simple projects which will give you a hands-on lesson about how weather and weather instruments work, and how to make a homemade weather instrument at home.
None of these projects can completely replace a fully featured electronic weather station, but they are useful for understanding what the weather station is displaying. These procedures will also help you on how to make weather instruments for school projects.
Experiment #1: Make a Cloud In a Bottle
Have you ever looked up at a cloud and wondered how a cloud is made and how it gets up there? In this simple demonstration, we will see the process in miniature inside of a 2-liter soda bottle. What happens inside of the bottle is very similar to what occurs in the atmosphere.
The mechanism of the experiment is to pressurize the air inside the bottle and then releasing it. The pressure release is very sudden in the bottle while it happens rather slowly in nature, but the results are basically the same.
Experiment #2: A Homemade Thermometer
This demonstration shows us how a liquid thermometer works. There are many variations on this experiment, and it is very simple to do with just a few materials that you probably have around the house. Some people have made these thermometers using plastic water bottles.
The problem with the plastic is that it is flexible so it is easy to get a higher reading if you accidentally squeeze the bottle. However, either glass or plastic will work for demonstration purposes.
What keeps the bottle thermometer from being a useful weather instrument is the difficulty in calibrating the instrument and devising an accurate and readable scale. We are including this second link which shows how commercial and scientific grade thermometers are made.
Experiment #3: Making and Using Homemade Barometers
As you may recall from our discussion of weather instruments, there are two common types of non-electronic barometers, the liquid barometer and the aneroid barometer. Simple aneroid barometers are quite easy to make as you will see in the video. What makes this project even more interesting is that your homemade barometer is actually useful for making short-term weather predictions.
The homemade barometer does not have to be calibrated in atmospheres or Inches of Mercury to make predictions, rather, observe the change in the reading. If the needle is lower than the last time you looked at it, there may be a storm coming. If the needle is rising it indicates rising pressure and fair weather is on the way.
Traditional liquid barometers are made using mercury as the liquid. However, mercury is not only expensive to obtain, it is highly toxic to work with. It is possible to make a scientifically accurate barometer using water, but the tube must be very long. This video shows how to make a smaller barometer that is accurate enough for weather prediction and will look nice on a shelf.
Experiment #4: A Simple Wind Vane
Knowing which direction the wind is blowing from can be important for predicting the weather in your area. Wind blowing from the interior of the continent is usually dry and cold, depending on the time of the year, while wind coming from the sea may be warm and moist, bringing storms.
A wind vane is one of the most basic of weather instruments. You may have seen decorative wind vanes on top of barns and other tall structures. Even though they seem like they are a decoration, they can serve a useful purpose. The wind vane project in the video will not last as long as a metal one, but it will demonstrate how the device works.
Experiment #5: Rain Gauge
Monitoring a simple rain gauge is a good way to develop the habit of observing and recording weather conditions. Your weather notes can be used for a school science presentation, not to mention that it is good information to have on hand. The rain gauge can also be used to monitor irrigation. Simply place the gauge on the lawn when you turn on the sprinkler and you will keep the grass green without overwatering.
How the National Weather Service uses information gathered by storm spotters and storm chasers to help everyone be safer.
How to find a storm chasing mentor.
How to conduct your own storm chase.
You may have seen exciting video footage of a tornado or thunderstorm on TV or YouTube, or perhaps you have seen storm chasers on reality TV or in the movies Twister (1996) or Into the Storm (2014). Some of the footage you see is from people who just happen to have a camera handy when a storm comes their way, but the best of it is probably shot by Storm Chasers who make it their business to go out and observe radical weather first hand.
Seeing a violent storm up close, feeling the strength and violence of the wind and feeling the bite of the rain and hail can be a frightening and exciting experience at the same time. In fact, the whole idea of storm chasing seems a little crazy to most people who are more likely to seek shelter when that a storm is coming.
For people who do enjoy the thrill of experiencing violent weather first hand, there is the satisfaction that even a clip of a storm shot with a phone camera can help researchers and scientists to better understand tornadoes and thunderstorms.
Photo by Brian A Morganti/stormeffects.com
A Storm Chaser is anyone who looks for heavy weather conditions, no matter what their motivation. They may be interested in collecting scientific data, producing news or media coverage, seeking adventure or simply curious to know what it is like in a severe storm. Very few people actually make a living as storm chasers. Most of the footage and data available comes from people who take up storm chasing as a hobby.
The National Weather Servicedoes not encourage people to take up storm chasing, in fact, since their mission is the protection of life and property from the damaging effects of weather, NWS does all they can to keep people away from dangerous storms. However, the Service does provide training for Tornado and Thunderstorm Spotting, and spotters are a vital link in the heavy weather warning system.
As exciting and dangerous as storm chasing can be, it is probably not the best pastime for an adrenaline junkie. Yes, there will be a lot of adrenaline if you actually find yourself face to face with a tornado, but the chances to actually see a storm up close can be few and far between. Probably the easiest way to enjoy storm chasing is to sign up for a storm chasing tour group.
These can cost thousands of dollars, and even though they take reservations months in advance of tornado season, none of the operators can really guarantee to get you up close and personal with a major storm. You can expect to spend the entire 6-10-day tour crisscrossing the Great Plains in a van with the possibility of seeing nothing more than some beautiful scenery.
Check out F5 Tours, Silver Lining Tours or Tempest Tours to see what is included in their packages.
It is possible for a new storm chaser to “go for it alone”, but it is better and safer to find a mentor, an experienced storm chaser who knows what they are doing to show you the ropes. Of course, the best mentors will be someone who has a great deal of storm chasing experience, and they are also the sort of people who will have little patience with someone who is not going to take the hobby seriously.
An online forum likeStormtrack is a great place to learn about storm chasing and to introduce yourself to experienced storm chasers.
Here are some tips that will help an experienced storm chaser take you seriously. Begin by learning as much about storms and weather as you can.
Training as astorm spotter with the NWS is a good way to show that you take learning about weather seriously.
Making observations on a home weather station and recording them is another way. Remember, you don’t always have to chase storms to learn about them, sometimes they will come to you. Learning to understand everything that your weather station is displaying and what it means is a great education for a beginning storm chaser. With the correct accessories, you can even display your home weather station data on your personal weather website and connect to an on line weather station network.
There are a few skills that storm chasers need to develop in order to get the most out of their hobby. The first is to learn how to monitor a VHF radio for weather alerts from the National Oceanographic and Atmospheric Administration. Portable VHF radios are probably the most useful because you can leave them plugged in while you are monitoring and take it in the vehicle with you during a chase. Our recommended choice is the Uniden MHS75 that you can find on Amazon.
Uniden MHS75 Handheld Submersible Marine Radio
Once you have determined that there is a storm in your area to chase, locate it on a map and program the information into a GPS device. It is best for storm chasers to work as a team of at least two. The driver needs to keep his full concentration on not only the normal hazards of driving, but heavy weather can present sudden and unexpected hazards, such as flooded roads, downed power lines, low visibility, and other confused drivers who are not prepared for the same dangers.
One of the team members should take care of all the navigation duties, tracking the storm’s progress from the radio, finding its location on the map, and tracking the data from a GPS device. When the tornado or thunderstorm is in sight, drive parallel to its track to follow it. When it is safe, pull to the side of the road, turn on the hazard flashers, and take pictures of the event. It is best to remain inside the vehicle while recording to protect against a lightning strike.
Even though your team will be tempted to get as close as possible to get the best pictures, keep the following in mind for safety.
The hazards of driving in heavy weather include standing water on the road which can cause hydroplaning and a loss of control, low visibility, hail which can make the road slick and damage the vehicle, and heavy winds that can make it hard to control the vehicle.
Break off the chase and move towards safety when lightning begins striking every 15 seconds or hail begins falling in sheets.
After a successful storm chase, you can submit a recording to the event to a branch of the National Weather Service who will use your images to create a better understanding of weather hazards, post the video on your website or on YouTube, and then congratulate yourself for facing and experiencing Nature’s fury up close and personally.
How the Military needs meteorologists and how they are trained
How you can become an amateur meteorologist with a home weather station
A meteorologist is a scientist who studies weather and the atmosphere. They work for government agencies, private business, in education, consulting and research services, and for TV and radio stations. The public is most familiar with meteorologists who provide weather forecasting in media.
Most professional meteorologists will attain a four-year college degree in meteorology or a related science. The course of study will be heavy on math because modern weather forecasting depends upon compiling data from hundreds or thousands of observation sites then creating and analyzing computer models based on the data.
If you plan on studying meteorology, it is best to start in high school. If your school offers calculus, computer programming and physics courses, you can start college ahead of the game. If you just want a straightforward and funny tool for your kid to start with, check out the Scientific Explorer Wacky Weird Weather Kit. We guarantee that both you and your child will have a ton of fun with this game.
Scientific Explorer Wacky Weird Weather Kit
Another option to receive the latest “Hands On” meteorological training is through military service. Both the US Navy and Air Force require up to date and accurate local weather information to accomplish their missions. Both services use enlisted specialists to collect and interpret both locally collected weather data as well as satellite data.
An enlisted weather specialist will be required to complete Enlisted Basic Military Training (“Boot Camp”) for their service, and then attend a specialized technical school. The Navy’s Aerographer’s Mate (AG) Class A Technical School and Air Force Weather Specialist technical training is held at Keesler AFB, Mississippi. Your local Military recruiter can provide more detailed career information.
Many of the instruments that a professional meteorologist uses are just like the ones that come with a home professional weather station. In fact, many weather hobbyists are able to connect their weather stations to a central data collection point so that weather scientists can use the data collected by amateurs for weather modeling and forecasting.
Review Quiz:
Q1: Why is studying math so important for meteorologists?
Q2: What are two military enlisted career specialties that work with weather and gathering meteorological data?
Answers:
A1: Meteorology is a science of observation, and the most efficient and accurate way to make sense of the thousands of data points gathered around the world each day is through complex computer-based mathematical models.
A2: Air Force Weather Specialists and Navy Aerographer’s Mates.
The difference between weather and climate and how they are related
The Five components that generate climate
The Köppen climate classification system
Climate change
After the TV weather person makes their report and prediction on the local station, many times there will be a short clip about the climate, often with dire warnings of how changes are going to mess everything up and that it is all mankind’s fault. You may have heard people say things like
“The weather is going to be exceptionally hot today, it must be because of global warming” or “We had a really bad winter last year because of climate change”.
These statements can be confusing because weather and climate are related, but they are not the same thing. On the NASA Climate page, it says that
“The difference between Weather and Climate is a measure of time”
and even that is not quite accurate. Comparing weather and climate is not like comparing apples and oranges, nor is it like comparing an orange to a crate full of oranges. It is more like comparing oranges to fruit. In other words, oranges are fruit, and there are many fruits that have a lot in common with oranges, but not all fruit is like an orange.
Weather is an important part of climate, and when we classify climates one of the important things to look at is the average weather over an extended period of time. The climate of a certain region is generated by the interaction of five worldwide components:
the atmosphere where weather is generated
the hydrosphere which is the mass of water found on below and above the planet
the cryosphere or regions of solid ice such as the polar caps
the lithosphere or rocky outer shell of the planet
and the biosphere or the living things on the planet.
The most common way of classifying climates is using the Köppen Climate Classifications. The classifications were first published in 1884 and have been modified several times since. They were originally based on the notion that native vegetation is the best expression of climate.
The system is divided into five main groups (A, B, C, D, E) and each group is further divided into types. Each climate type may be represented by a 2-4 letter symbol. For example, Miami has an A or Tropical monsoon climate; Denver has a B or Dry Steppe climate with at least one month of average temperatures below freezing, Los Angeles has a C or Mediterranean climate with hot and dry summers dominated by subtropical high-pressure systems, and Chicago has a D or Continental climate with the warmest month averaging greater than 72°F. Group E climates are polar and alpine zones.
The Köppen climate classifications are useful for travelers and geography students as well as those studying weather and climate.
Paleoclimatology is the study of ancient climates and weather patterns before modern record keeping. We know that the worldwide climate has changed many times, just like it is changing now. There are many theories and reasons behind climate change ranging from an “end of the world” scenario caused by pollution and other manmade factors to a natural cycle that would occur no matter what man does.
This is not a forum to debate the various causes of climate change, let alone fix blame. We will just point out that climate change is happening, it has happened before, and species and civilizations who can adapt will survive and thrive.
Review Quiz:
Q1:What are the five world-wide elements of climate?
Q2: What expression of climate are the original Köppen climate classifications based on?
Q3: What can the study of paleoclimatology teach us about climate change today?
Answers:
A1: The atmosphere, the hydrosphere, the cryosphere, the lithosphere and the biosphere.
A2: The system was originally developed by Wladimir Köppen, who was a botanist as well as a climatologist. He based his climate classification system on the observation that certain types of plants grow in certain regions but not in others. In the decades since the Köppen climate classifications has come into use, we have a better understanding of how a saguaro cactus and a live oak tree have different climatic needs, and how climate change over time affects how plants grow and thrive
A3: Through paleoclimatology, the study of climate before records were kept, we know that regional and planet wide climates change. These cycles are not entirely predictable, and it is inconclusive how much effect man-made factors have influenced climate change.
How hurricanes and tropical cyclones are formed and named.
Typical, everyday weather is important to watch and fun to keep track of. It is the weather we see most of the time and the type of weather that has the greatest influence on our lives. Some of the real fun of observing weather happens when the weather gets a little bit crazy and even dangerous.
One of the most common types of violent weather is a thunderstorm or electrical storm. Thunderstorms can range in intensity from a really short and intense rain burst with some lightning and thunder to a full blown tornado.
Besides thunder and lightning, one of the defining characteristics of a thunderstorm is its intense winds, especially the vertical winds. A thunderstorm is generated when warm, moist air is blown upward. As the air rises towards the cooler higher altitudes it reaches the dew point and the moisture in the air begins to condense and form snow or raindrops.
As the drops collide and form bigger drops, they begin to fall. As the water drops fall, they will cause a localized cooling effect, which causes even more winds to blow.
When the different temperature air masses rub against each other they can build a static electrical charge. The molecules of air and water rubbing together set up an electrical imbalance just like when you scuff your stocking feet across a carpet. Usually, the top of the thundercloud is positively charged while the bottom is negatively charged, but sometimes the cloud moving over the ground can give the ground a negative charge.
When the total charge is big enough, the electrical structure of the atoms in the air between the two charges begins to break down or ionize. This ionized air is highly conductive, and what we see as lightning is the plasma energy created when the charge between the positive and negative zones equalizes.
The sudden increase of temperature and pressure along the lightning bolt causes a rapid expansion and contraction of air which we hear as thunder.
The most severe thunderstorms are called supercell thunderstorms, and they occur when the wind changes direction and speed at different heights, and there is a separation between the updraft and downdraft zones. Tornadoes are often associated with supercell storms.
The name tornado comes from the Spanish word for thunderstorm. The funnel cloud of a tornado is formed around a localized low-pressure zone. The condensation of moisture inside the funnel and the dust kicked up by the intense surface winds allow the funnel cloud to be visible.
The winds associated with most tornadoes are below 110 mph and the tornado may travel a few miles before dissipating. A severe tornado may have winds up to 300 mph and travel for dozens of miles.
Here is some interesting Trivia: The first time a Hollywood movie successfully used showed a tornado effect on screen was in The Wizard of Oz (1939). This was decades before digital effects and green screens were even considered, and the science of weather forecasting was still primitive enough that sending a crew out to Kansas in hopes of filming a real tornado was out of the question.
Special Effects director A. Arnold “Buddy” Gillespie attempted to use a water vortex and a rubber cone to fill in for his tornado, but the results were not realistic. Finally, he noticed that the windsock at the local airport was the shape he was looking for. He made a 30′ muslin sock which he hung from a crane over the set.
The bottom of the fabric cone was attached to a car below the stage floor, and compressed air hoses blew dust and wind into it to simulate the debris which swirls around the base of an actual tornado.
The Weather Channel named the tornado scene from The Wizard of Oz in their list of Great Moment in the history of weather. The scene inspired several generations of meteorologists to take up the science.
A hurricane is a type of tropical cyclone and is one of the largest and most intense storms on the planet. Tropical cyclone refers to where the storm forms, and its winds, which circle around a low-pressure center or eye. Cyclones in the Northern hemisphere turn counterclockwise and clockwise in the South. The storms are generally “born” over warm tropical oceans, but rarely within 5° of the equator.
Warm, moist winds blow radially toward the low-pressure area at the center of the storm, feeding it with more and more energy. A hurricane can grow to between 60 and 2,500 miles in diameter.
Hurricanes are such large weather events that they are traditionally given names. Names are generally selected in advance for each season and assigned in alphabetical order. Tropical cyclones which originate in the Atlantic are referred to as hurricanes and those which affect the Western Pacific region are called typhoons.
In case of Hurricanes or other extreme weather events, safety should be your first concern, therefore we recommend to prepare in advance. You could either prepare an emergency kit buying all the items one-by-one or use ready-made kits.
Review Quiz:
Q1: What are the defining characteristics of a thunderstorm?
Q2: What makes a tornado funnel cloud visible?
Q3: What gives a hurricane or typhoon its energy?
Answers:
A1: Lightning, thunder, and intense winds
A2: What we see as a funnel cloud is the condensing moisture inside the low-pressure zone along with the dust and debris picked up by the intense winds.
A3: The storm gains energy and intensity as the low-pressure center travels over hundreds of miles of warm, open ocean water.
How humidity is the amount of water vapor in the air and relative humidity is the measurement of how much moisture is present versus how much moisture the air can hold in a certain temperature
How water changes its physical state from solid ice to liquid water to gaseous vapor depending on temperature.
That the changing state of water drives the water cycle and the water cycle drives the weather
How precipitation occurs when water vapor in the air condenses as the air reaches the dew point
Barometric or atmospheric pressure and how low pressure air rises and high pressure air sinks through the atmosphere.
If you sat down and listened to strangers meeting and getting to know each other, what would they be talking about?
Most of the time they will be talking about the weather because it is something that we all have in common. There is even an old joke that says “Everyone talks about the weather, but nobody does anything about it!”
When weather becomes subject to study or a hobby, it is good to understand the language that weather scientists, formally called meteorologists use. Meteorology seems like a very complex science, and it is because the weather is something that happens over the whole planet. However, the concepts that every meteorologist or weatherman uses are fairly simple to understand.
Humidity
In the last section, we learned that water has three physical states, solid ice, liquid water and gaseous water vapor. Humidity is the presence of water vapor in the air. The mix of gases in normal air is usually around 78% nitrogen, 21% oxygen, 1% argon, 0.04% carbon dioxide, and varying amounts of other gases, including water vapor. The normal concentration of water vapor is about 1%, but air can hold more or less water vapor depending on its temperature.
Since air at specific temperatures can hold a certain amount of water, we can measure how much water vapor is in the air compared to how much the air can hold at that temperature. This is called relative humidity.
When the air can hold no more water vapor, we say that it is saturated, or 100% relative humidity. The lower the relative humidity is, the more readily liquid water will evaporate into it, and as water evaporates it takes heat energy with it. When warm air, which can hold a lot of moisture, cools, it may approach the dew point, which is the temperature where the water vapor begins to condense back into liquid.
This is what drives the water cycle, and the water cycle is what drives weather. In a simplified fashion, the cycle goes something like this:
As the sun heats the air over the ocean, the warmer air is able to hold more of the water vapor that evaporates from the surface of the water.
As the air warms, it also rises and cooler air moves in to take its place.
As the air rises it cools, and the cool air replacing the warm air causes winds to blow.
As the first mass of warm air rises, the winds may blow it over a land mass where it may cool to the point that it cannot hold the same amount of water vapor. The water condenses out of the air as clouds and eventually precipitation in the form of rain or snow that falls on the land, and runs down hill to lakes and rivers, eventually to the ocean and the cycle starts again.
Precipitation
Precipitate is a fancy word which means to fall.
When the air temperature drops below the dew point, the water vapor begins to condense into water droplets, and the water begins to give up the heat energy it absorbed during evaporation. When this happens up in the sky we see it as clouds, if it is at ground level it is fog or mist.
Mist and fog are classed with precipitation because they form like other types, but the water droplets are so small that they remain suspended in the air rather than falling.
Dew forms on objects on the ground that are at a temperature lower than the dew point of the air. If the object is below the freezing point of water, frost forms. When water vapor in clouds begins to condense, either on dust particles or simply into droplets, the same thing occurs. If the air in the cloud is below the freezing point, ice crystals form. As more water condenses and freezes, the crystal grows until it becomes a snowflake, and when the flake grows too heavy to be supported in the air, it falls to the ground.
Rain forms in two basic ways. The water droplets in a mist or fog collide with each other until they form a drop that is too big to remain suspended and it falls as rain, or a snowflake will go through a layer of warmer air as it is falling; and as the flake melts it becomes a rain drop. Sometimes in a thunderstorm, the flake may begin to fall and partially melt until the winds catch it and carry it higher where it takes on more water and freezes again.
This cycle continues until it is too heavy for the winds to carry back aloft and it falls as hail.
Barometric Pressure
When we talked about water we mentioned the three states of matter, solids, liquids, and gases. Solids are, well, solid, they pretty much hold their shape. Liquids and gases are fluids, which means that they change their shape to suit whatever they are being held in. Gases are much less dense than solids or liquids, which means that there is more room between the molecules of a gas. This means that gas can be compressed, the molecules squeezed together.
Since there is already less room between the molecules of a liquid, a liquid cannot be compressed.
Imagine a cube of air on the ground next to your chair, a foot high, a foot deep and a foot long. Now imagine another cube of air the same size stacked on top of the first one. Once you have the second cube in your imagination, keep stacking the cubic feet of air on top of each other clear up to the sky.
Each cubic foot of air has weight, and they are all pressing down on the cubic foot of air at the bottom. This is called pressure, and it forces the molecules of the air closer together.
We know that a piece of wood is less dense than water and a rock will be denser, so the wood will rise to the top if you push it down into a bucket of water while the rock sinks to the bottom. In the atmosphere, air with greater density (higher pressure) sinks while less dense (low pressure) air rises. If there is an area of high pressure over your house, you can expect generally fair weather.
A low pressure, however, generally indicates stormy weather. This is because as the air rises through the atmosphere it cools rapidly to the dew point where the moisture in the air gives up the energy it gained during evaporation, and that energy is what drives a storm.
Temperature
We think that temperature is a measure of how hot or cold something is, but that does not tell the whole story. How hot or cold something is an expression of how much heat energy is present, with more energy the molecules move around and run into each other more.
As the energy increases, so does the temperature, and as energy is given up, the temperature falls, but only to a certain point. We know that at sea level, water freezes at 32°F. That means that the water is giving up energy as the temperature falls, but at 32°F the liquid water still has too much energy to freeze solid. The water needs to give off the excess energy to the surrounding air before it can change its physical state.
You can demonstrate this by putting a clean glass of water in the freezer for a couple of hours. If you time it just right you can take the glass out of the freezer with the water still in liquid form, but when you give the glass a little shake crystals begin to form and the water freezes into slush. Before it freezes, the water is said to be “supercooled”.
Sometimes you get “superheated” water from a microwave oven, which can be a dangerous situation. When the temperature of water at sea level approaches 212°F the temperature stops rising as the water absorbs enough heat energy to change its physical state from liquid to gas.
Sometimes when you heat water in the microwave using a clean, smooth glass or cup the temperature of the water may exceed the boiling point. As soon as to give the cup a small shake, it suddenly boils which can cause a nasty burn.
Temperature is commonly expressed using either the Fahrenheit scale or the Celsius scale, which can get a little confusing. Most scientists and people in other countries use Celsius, but the weatherman on your local TV station and most of the people you know use Fahrenheit.
Sometimes when you are watching a news report from overseas you may hear the reporter say that it is 22°C, and you are not sure if that means it is hot or cold.
Tip: Most people need a conversion chart or a calculator to convert between the two scales, but here is an easy way to do it in your head. This method is not completely accurate, but it is close enough that you can understand temperature in a conversation.
When you hear a temperature in Celsius, simple double the figure in your head and add 30. The actual conversion formula is to multiply by 1.8 and add 32, but rounding will get you close enough.
In this example, 2 x 22°C = 44, add 30 and we get 74°F. If we had used the formula and a calculator we would have gotten 71.6, but either way we can tell that it is a nice day.
Review Quiz:
Q1: What is 100% Humidity?
Q2: What is “the dew point”?
Q3: How does hail form?
Q4: What do we call the weight of air forcing air molecules closer together?
Q5: How hot is it if you hear that the temperature in Sydney, Australia, is 18°C?
Answers:
A1: At 100% relative humidity, the air is “saturated” and unable to absorb any more moisture through evaporation.
A2: When the temperature of the air falls to the point that the moisture in the air begins to condense, it is said to be at the Dew Point.
A3: When air rises into the cooler upper atmosphere, the moisture reaches the dew point and begins to condense into tiny droplets of water. As the temperature continues to drop, the droplets form ice crystals, on which more moisture condenses. When the crystals become too heavy, they begin to fall as snow, and may begin to melt. In a thunderstorm, the partially melted flakes can be blown higher where they refreeze and absorb more condensing moisture. After several falling, melting and refreezing cycles they finally fall as hail.
A4: Barometric Pressure
A5: For a quick estimate, 2 x 18 = 36, add 30 and we see that it is about 66°F in Sydney, so it is a nice day. For a more accurate conversion, 1.8 x 18 + 32 = 64.4°F, so 66 degrees is close enough for most things.
How weather is what is happening in the atmosphere
The difference between climate and weather
How heat from the Sun is the energy that drives weather
Introducing how moisture in the air absorbs and releases energy
Every day before you go outside you probably take a look out the window to see what the weather is doing. Most people are happy if it will be sunny and warm so they can put on shorts and play in the backyard, and if it is rainy and cold they would rather stay indoors with a warm drink.
It is easy to think of weather as simply being nasty or nice, but there is a lot more going on than just these two opposites. Weather is what is happening in the atmosphere at a particular place, and the weather is always changing.
There is weather inside your house as well and we will be looking more closely at the inside weather to help us understand how the weather outside works.The climate is in the news a lot these days. Climate and weather are related, but they are not the same thing, and it is hard to understand climate until you understand weather.
Weather is what is happening in the atmosphere at a certain time at a certain spot while climate is a study of the weather in an area over a long period of time.
Looking out the window seems pretty simple, we see that it is either sunny or cloudy, windy or calm. In fact, many different things influence what the weather is doing in your backyard. Some of them are hundreds or thousands of miles away from where you are. The two most important things that affect the weather are heat and moisture.
The heat comes from the Sun shining on the Earth. Since the Earth is tilted relative to the Sun, the area around the Equator receives more heat than at the poles. Also, the Earth is spinning, so the everywhere that the Sun is shining now will be in darkness in a few hours.
In general, warmer air rises and cooler air comes in to replace it. The new air warms and the cycle continues. It’s like putting a big pot of water on the stove to boil; the water in the bottom of the pot near the middle gets hot first because it is closest to the fire. We can see the water in the pot begin to circulate in a process called convection.
As the hottest water in the bottom of the pot moves up, it cools a little bit and the cooler water moves to the bottom and begins to absorb the heat from the element. When all of the water in the pot becomes so hot that it cannot absorb any more heat, it boils.
The heat from the Sun is the energy that drives the weather, just like gasoline is the energy that drives a car. Just a tank full of gas will not make a car move, of course. It needs an engine to convert the energy of the gasoline into motion. The engine in the atmosphere that drives the weather is water, or more specifically moisture.
You may have been taught that water exists in three states of matter: solid, liquid, and gas in the forms of ice, water and vapor or steam.
We are told that water changes between these states according to temperature: water below 32°F occurs as frozen ice, between 32°F and 212°F water is liquid and above it is steam. However, there is another factor that is just as important as temperature to determine the physical state of water; pressure.
Let’s go back to our pot on the stove. What if we went outside and filled the pot with snow?
As soon as we brought the pot inside the ice in the snow begins to melt, and it melts even faster when we put it on the stove. Not only does it get hotter from the element, but the convection we saw in the boiling water is circulating to help the snow melt faster. Remember that convection it is the transfer of heat through the movement of particles; warm particles rise, cool particles fill in the space below.
The convection will continue until the liquid water boils and becomes steam unless we put a heavy lid on the pot. If the lid is heavy enough and seals the pot so that no steam can escape, there is too much pressure for the water to boil, and the liquid water can be hotter than 212°F. The opposite occurs when the pressure is low. At high altitudes, water boils at a lower temperature.
We will look at temperature, pressure and moisture a lot closer in the next section.
For now, just keep in mind that everything we see as weather exists because of three things, heat energy from the Sun, air moving because of temperature differences, and more or less moisture in the air because of temperature and pressure.
Review Quiz:
Q1: What provides the heat energy that drives weather?
Q2: What causes the air in the atmosphere to move?
Q3: What are the three physical states of water?
Q4: What are the three basic elements of weather?
Q5: What provides the heat energy that drives weather?
Answers:
A1: The Sun
A2: Differences in temperature cause the air to move. Warm air tends to rise and cooler air that sinks rushes in to replace it.
A3: Solid ice, liquid water and gaseous vapor.
A4: Heat from the sun, temperature differences in the atmosphere, and moisture in the air.
Learn how kids can learn to love the planet by learning how weather works
Learn how we can learn about weather and how it works
Learn basic safety measures to take in case of dangerous weather
One of the greatest things about being a parent is discovering the world through their young eyes. How many common things have become extraordinary when you share them with your kids? They are even more special when they are something that they can share with you.
It is never too early to begin teaching your kids to love the planet they were born on. And the best way to love it is to learn about it. There are any number of ways to do this, a trip to the zoo or aquarium, a camping trip in the woods, a hike in the local park, all are great ways to introduce the wonder and majesty of nature to a young mind.
But the opportunities are not as easy to find as we would like. These things take planning and preparation, but the weather is always there, just outside our windows.
In fact, there is weather inside the house as well, and we will study that as well so that we can understand what is going on in the sky outside. Eventually, we will be able to see how a dust storm on the other side of the planet influences whether or not you will have a White Christmas.
But our main focus will be why is it sunny one day and stormy the next, what is really going on when snow or rain is falling, even why it can be raining at home but sunny at school!
This is a good time to begin thinking about weather and storm safety.
Storms that bring thunder, lightning and even tornadoes can be frightening for small children, but understanding the weather and why it is doing what is doing can take away some of the scariness. It does not make the storms less dangerous, but being less frightened, kids are less likely to make mistakes.
We will learn more about specific weather safety hazards as we go along, but here are some important safety tips to keep in mind now:
Always be aware of the weather. Of course, you should always take a look through the window before you go outside to see if you need a jacket or coat, but take the time to check the forecast, either from TV or radio, online, or from your home weather station, to see if the weather could get worse.
If the dangerous weather is predicted, it does not mean that it will happen but know the signs so you can watch for them. If the sky suddenly fills with dark clouds and it starts to rain, seek shelter. Not only will you be more comfortable, you will be safe from lightning or tornadoes.
The best place to be is in a building or a car with the windows rolled up. Avoid exposed shelters like metal sheds, baseball dugouts, bleachers, or under a lone tree.
If there is lightning in the area and you cannot find shelter, crouch down in an open area, at least twice as far away from the nearest tree as it is high, and cover your ears to prevent hearing damage from thunder.
Stay away from water and metal. Both will conduct electricity and may attract a lightning strike.
If there is tornado danger, remember to D.U.C.K. – “duck” :
Get DOWN to the lowest level of the building,
Get UNDER something solid like a table or a desk,
COVER your head to protect from falling debris,
And KEEP inside the shelter until you are sure the danger has passed.
Review Quiz:
Q1: Why is it important to understand “inside weather”?
A1: The processes that occur in the atmosphere inside a building are the same as happen outside. If we can learn what is going on in the small scale, it is easier to understand what is happening on the larger scale of the outdoors.
Q2: What is the safest place to be in a sudden storm?
A2: Seek shelter in a building or in a car with the window rolled up.
Q3: How do you D.U.C.K. from a tornado?
A3: Get DOWN to the lowest level of the building, get UNDER something solid, COVER your head, and KEEP inside until you are sure the danger has passed.
One of the team members should take care of all the navigation duties, tracking the storm’s progress from the radio, finding its location on the map, and tracking the data from a GPS device. When the tornado or thunderstorm is in sight, drive parallel to its track to follow it. When it is safe, pull to the side of the road, turn on the hazard flashers, and take pictures of the event. 
The name tornado comes from the Spanish word for thunderstorm. The funnel cloud of a tornado is formed around a localized low-pressure zone. The condensation of moisture inside the funnel and the dust kicked up by the intense surface winds allow the funnel cloud to be visible.
