Meteorology Archives - Eva Varga


December 4, 2015

We have recently moved from the northern end of California’s Central Valley at the foothills of the Cascade Mountains to the southern Oregon Coast. One of the most noticeable differences between these two areas is the weather.

Oregon Coastal Winds: A Nature Study @EvaVarga.net
Photograph by Jamie Crawford

In Redding, we enjoyed a hot Mediterranean climate. Here on the coast, the weather is more moderate with partly cloudy days and windy afternoons the norm. It is the perfect place to dive into a study of Oregon’s coastal winds.

I recently wrote an article for the Handbook of Nature Study monthly newsletter describing ways in which you could undertake a study of wind. If you don’t already subscribe to Barb’s newsletter, I encourage you to do so.

Wind results from pressure gradients, differences in air pressure from one place to another. When high pressure and low-pressure areas come close to each other, air from the high-pressure area will move into the low-pressure area, creating wind. Because of the rotation of Earth, the air will not move directly toward the low-pressure area. Instead, it spirals in, creating a cyclone. A cyclone is any weather system with winds around a low-pressure area. The wind will continue until the pressure between the areas is equalized.

Students often have misconceptions about wind and where it comes from. Before beginning a unit study or lesson on the wind, begin with a discussion to reveal their ideas of wind and its origins.

Oregon Coastal Winds

As Meriwether Lewis observed during his encampment along the coast in the early 1800s, it can get windy on the Oregon Coast. In the winter, storms approach the coast from primarily a westerly direction. In this case, strong southerly winds occur ahead of the storm’s advancing frontal zone, as higher pressure to the south tries to compensate for falling pressures to the north. Once the front passes inland, winds shift to westerly.

The winds from the Land brings us could [sic] and clear weather while those obliquely along either coast or off the Oceans bring us warm damp cloudy and rainy weather. The hardest winds are always from the S.W.
~ Meriwether LewisJanuary 311806at Fort Clatsop

Such an observation is completely true in the winter. However, had Lewis and the other members of the Corps of Discovery experienced a summer along the Oregon coast, they would certainly have experienced other conditions. The prevailing winds shift to northwesterly along the coast throughout the spring and falls off remarkably along the entire coast during the summer months.Oregon's Coastal Winds: A Nature Study @EvaVarga.net

High Wind Advisory

Winter is a great time to visit the Oregon coast and watch our magnificent winter storms. There are at least a few fairly nice days in between the stormy squalls and near-gale force winds.

The winter storms are one of the things I like best about living on the coast. Meteorologists have stated that several storms are expected to hit the Northwest coast this week and perhaps through much of December. According to AccuWeather.com,

The storms, which will vary in intensity and location, will hit every one to three days with waves of drenching rain, heavy mountain snow and gusty winds.

Our rain gear is packed and we will head out periodically to measure the strength of the wind with our Kestrel 1000 Pocket Wind Meter. Our plan is to do this several times over the course of the year to get a feel for seasonal changes.

Take it Further

1) Students may be interested in investigating storms, like tornadoes, in which pressure differences between the two areas are very great. This would create an opportunity to talk about safety precautions that should be followed in tornadoes and strong wind storms.

2) A discussion of the Coriolis Effect may also be appropriate. Important to airplane and rocket navigation, the phenomenon of the Coriolis Effect results from the rotation of Earth.

3) When the children were younger, I introduced them to the concepts of air pressure and wind with a couple of simple activities. As I shared in this post, the air in the balloon is pressurized. The air around the balloon has a lower pressure than the air in the balloon. When the balloon is opened, the high-pressure air rushes out to a region of low pressure. This is the same principle that governs wind – though there are some key differences between the model and reality.

4) Wind is an important alternative source of energy. The history of wind machines, modern wind machines, the economics of wind power, and the environmental aspects of wind power can also be explored. Challenge students to build a windmill of their own using Fischertechnik or other building systems. How can you improve the efficiency of their design?

5) Find a poem or musical piece that was inspired by wind or other weather. Better yet, write your own!

Who Has Seen the Wind?
Who has seen the wind?
Neither I nor you.
But when the leaves hang trembling.
The wind is passing through.
Who has seen the wind?
Neither you nor I.
But when the trees bow down their heads,
The wind is passing by.
~ Christina G. Rossetti



November 1, 2015

Ever since the continents were all mapped, people had noticed that many coastlines, like those of South America and Africa, looked as though they would fit together if they could be moved like puzzle pieces.

Alfred WegenerWith his revised publication of The Origin of Continents and Oceans in 1915 (originally published three years prior), Alfred Wegener was one of the first to suggest continental drift and plate tectonics. In his work, he described a ‘super-continent’ he called Pangaea had existed in the past, broke up starting 200 million years ago, and that the “pieces drifted” to their present positions. Citing similar ancient climates, rock structures, and fossil evidence.  [ Frank Taylor, an American scientist, had published a similar theory in 1910 but his work attracted little attention. ]

When continental drift was first proposed by Alfred Wegener in the early 1900s however, it was met with skepticism by the scientific community. The proposal remained controversial until the 1960s, when it became widely accepted over a fairly short period of time. Today, the theory of plate tectonics is key to the study of geology.

However, Wegener is not only the father of the theory of continental drift, he was also the first to describe the process by which most raindrops form. This process is now called the Wegener-Bergeron-Findeisen procedure.

The Pangea Puzzle, Ice Halos, & Raindrops: The Influence of Alfred Wegener @EvaVarga.net

Photo by Greg Clements (Field Studies in Greenland)

During Wegener’s lifetime the process by which cloud particles reach raindrop size was not known, but there was some idea how much rain, even during summer, began as snow in the clouds. In 1784, Benjamin Franklin had suggested this, and in 1904, Wilson A. Bentley, who spent a lifetime studying snow crystals and raindrops, found supporting evidence for the conjecture.

“Perhaps the only thing that saves science is the presence of mavericks in every generation.” ~ Alfred Wegener

In his 1911 publication, The Thermodynamics of the Atmosphere, Wegener noted that ice crystals invariably grow at the expense of super-cooled droplets because the crystals have a lower equilibrium vapor pressure. He then suggested that raindrops might result from this competition between ice crystals and super-cooled cloud droplets. Read more in the article Introducing Precipitation from the Eyewitness Companions: Weather from DK Publishing.

Wegener had hoped to document this process in real clouds, but other projects intervened and he never returned to the subject. Thus, it was left to Tor Bergeron and W. Findeisen to develop and prove the theory in the 1930s.

He also explained two rare ice crystal halo arcs that bear his name as well. Ice crystals often form in the frigid air just above the Greenland ice cap and can produce spectacular halos. In a 1926 article, Wegener explained two relatively rare arcs that appear opposite the sun and are now named in his honor.

Biography

The Pangea Puzzle: The Impact of Alfred Wegener @EvaVarga.netBorn in Berlin on November 1st, 1880, Alfred Wegener, was a German climatologist and geophysicist.

From an early age he took an interest in Greenland. He studied in Germany and Austria, receiving his PhD in astronomy in 1904. No sooner did he finish his dissertation than he dropped astronomy to study meteorology, the new science of weather.

At a time when the conquest of the North and South Pole began to enjoy enormous international public attention, Wegener made his first expedition to Greenland as the official meteorologist on a two-year Danish expedition in 1906.

Wegener experimented with kites and balloons, pioneering the use of balloons to track air circulation. That same year, he and his brother Kurt set a world record in an international balloon contest, flying 52 hours straight. When he returned he took up teaching meteorology at the University of Marburg.

He was the first to use kites and tethered balloons to study the polar atmosphere.

His fourth and final expedition was in 1930 as the leader of a major Danish expedition to Greenland. He celebrated his fiftieth birthday on November 1, but shortly afterwards the team got separated, and he was lost in a blizzard. His body was found halfway between the two camps.

The Pangea Puzzle: The Influence of Alfred Wegener @EvaVarga.netBring it Home

Science MilestonesVisit my Science Milestones page to learn more about scientists whose discoveries and advancements have made a significant difference in our lives or who have advanced our understanding of the world around us.



September 1, 2015

In a series of posts this week, I will be sharing 5 Misconceptions in Science and providing lessons and activities to help dispel these conceptual misunderstandings. Today’s post focuses on common misconceptions in astronomy.

Misconceptions in Astronomy @EvaVarga.netMisconceptions in Astronomy

Misconceptions creep into the science of astronomy perhaps more than any other science. Surveys have found that even college graduates carry persistent misconceptions or even wildly incorrect ideas about the phases of the moon or the cause of the seasons.

Considering the following statements, which are true? Which are false?

 

1) The sky is blue because it reflects the blue color of the oceans.
2) The seasons are caused by the Earth’s distance from the sun.
3) The Moon’s phases are due to the shadow of the Earth falling on the Moon.
4) The bright glow of a meteor is not caused by friction as it passes through the Earth’s atmosphere.
5) There are no stars seen in Apollo Moon-landing pictures thus proving that these landings were staged.
6) The Hubble Space Telescope is bigger than all Earth-based telescopes.
7) Stars in the night sky do have color.
8) The Moon is bigger near the horizon than when it’s overhead.
9) In the southern hemisphere, winters are much warmer than those in the northern hemisphere.
10) X-rays are emitted from the eclipsed sun but these X-rays do not damage your eyes if you look at the eclipsed sun.

How to Dispel Misconceptions

To help foster the replacement of misconceptions with new concepts, students should be encouraged to ask questions. Additionally, they should be given ample opportunity to engage in hands-on experiments or demonstrations designed to test hypotheses.

Carefully selected demonstrations are one way of helping students overcome misconceptions, and there are a variety of resources available. Let’s take the second statement above and explore how we can dispel this common misunderstanding.

MISCONCEPTION #2

The seasons are caused by the Earth’s distance from the sun.

Studies have shown that as many as 95% of people— including most college graduates—incorrectly believe that the seasons result from the Earth moving closer to or farther from the Sun. In reality, the answer lies in the tilt of the Earth’s rotational axis away or toward the Sun as the Earth travels through its year-long orbit. Distance plays no role since the Earth actually is closest to the Sun during the first week of January.

This video embedded below uses a globe and a strip of thermochromic paper to show how the axial tilt of the Earth as it orbits the sun produces the changing season. This is an excellent hands-on activity in which to engage your students to dispel this commonly held misconception.

To further investigate this common misconception in astronomy, check out National Geographic’s lesson The Reason for the Seasons.

Using demonstrations is a great tool to help dispel misconceptions. Be careful, however, to choose models and demonstrations that do do not mislead or strengthen other misconceptions. A popular model of the solar system that shows the relative distances of the planets from the sun, shows the planets all rotating around the sun on the same plane rather than on independent three-dimensional paths.

5 Misconceptions in Science & How to Dispel Them @EvaVarga.net

Misconceptions in Science & How to Dispel Them (series introduction)

Misconceptions in Geology & Meteorology (coming Wednesday)

Misconceptions in Chemistry & Physics (coming Thursday)

Misconceptions in Biology (coming Friday)

You might also be interested in my 5 day series,  Discovering Peru, where you’ll have the chance to win a travel guide of choice from DK Publishing.

My post is one of many hopscotch link-ups. Hop over and see what others are sharing.

Hopcotch2015Statements 4, 7, and 10 are true.  Statements 1, 2, 3, 5, 6, 8, and 9 are false.

 



December 22, 20124

We love snow.  When we lived in Central Oregon – we were delighted with each snowfall.  Living now in Northern California, we don’t get to enjoy as often.  Mount Shasta is just far enough away that it would be a full day outing if we desired to go skiing whereas Mount Bachelor was near enough, we could go for just a few hours and still have time enough in the day for other errands or activities.  The first year we lived here, sadly, there was very little snowfall – even at Shasta.

Mt. Shasta shrouded in clouds as viewed from our deck.

When the snow fell this week – we were both delighted and heartbroken.  My father, brother, and sister-in-law were planning to drive down to spend the weekend with us for Christmas.  I-5 was closed off and on all through the end of the week and through the weekend. Even with chains, the delays and closures forced them to stay home.  As a small consolation, the kids and I chose to curl up with a few holiday books and do a little nature study to take advantage of the snow fall which coordinated perfectly with the Outdoor Hour Winter Snowflake Challenge.

Science Literature

One of the books we read was Snowflake Bentley by Jacqueline Briggs Martin. We’ve read it before but I learned that Buddy didn’t remember it so it was a new discovery for him (not surprising when you read my previous post and discover what what he was focused on that day).  Winner of the 1999 Caldecott Medal, it tells the story of Wilson Bentley.

From the time he as a small boy, he saw snowflakes as tiny miracles and was determined to capture these small wonders on film. His work and dedication revealed two things – no two snowflakes are alike and each one is based on a six-pointed crystal.

After the story, we watched a Brain-Pop video on snowflakes and googled snowflake images.  We had wanted to capture a few flakes to observe under the microscope, but it had stopped snowing by now and the snow on the ground was wet, melting off by early afternoon.  We noted, therefore, that we had an easier time illustrating snowflakes than Bentley would have.

Nature Journaling

We recorded in our journal that since the angle that the individual atoms in water form is 104°, ice freezes into a roughly hexagonal molecular lattice. This six-sided crystalline shape is reflected into the snowflake’s overall shape, causing snowflakes to have a 6-fold symmetry.  Here is a fun video from Khan Academy to help illustrate this fact, Snowflakes, Starflakes, and Swirlflakes.

Our nature journal entries … sadly, the image is not very clear. 

Coincidentally, we had created numerous paper snowflakes earlier in the week to send to Sandy Hook Elementary School.  Members of the school PTA are coordinating an effort to convert the new school students and staff of Sandy Hook will be housed in after the holiday break into a winter wonderland.

I love that as unschoolers, we were able to “seize the moment” and thoroughly integrate our curricular studies:  nature, science, writing, literature, biography, math, art, and service learning.  It was indeed a full day of learning but took only an hour or so of actual clock time.



January 29, 20093

On Tuesday, our Roots & Shoots club gathered in our room with the intention of studying the science of snow. Unfortunately, it hasn’t snowed in some time and we didn’t  have much of a snowpack to observe. I thereby had to make some modifications to my original plan.

Young girl examining fresh snowflakes on a black piece of paper
Capturing freshly fallen snow

Connecting Literature

After everyone arrived, I gathered the kids on the carpet and read aloud a favorite book, Snowflake Bentley. It is a rather lengthy story but most everyone was attentive and engrossed in the story. Everyone that is, except Buddy, who was much more interested in demonstrating his skills as a train engineer and Polar Express enthusiast. “Choo Choooooooooo!” he exclaimed loudly as he ran circles around the house. It took a little while to get him quiet – I was a little embarrassed – but he made us all chuckle.  [ One of the true joys of homeschooling diverse ages of children. ]

After the story, we got the wiggles out and then sat down in the office where I showed a short video clip which explained how snowflakes are formed. For most of the kiddos, I’m sure it went over their heads – but it was exposure and if nothing else, they will understand that snow is made of tiny crystals, none of which are exactly alike.

I then showed part of a second clip… which explained how to go about studying snow. I encouraged everyone to give it a try at home when it snowed again. I gave the adults a few handouts to take home.

A young girl captures snow as it's falling onto black contrasting paper

Art & Writing Activity

I then gathered everyone around the dining room table and showed them how to make paper snowflakes. I was surprised that most of the kids had never done this before so it was a delight. I had templates with valentine themed patterns (hearts, of course) to make it easier. I also encouraged everyone to create their own designs.

I didn’t anticipate the difficulty that some would have cutting into the thick layers of paper, however. Everyone, therefore, created at least one snowflake, but only the more experienced with scissors chose to make more.Sweetie loved it as I knew she would. The following day she continued to make snowflakes and we were able to create a curtain or arch in one doorway. See her post, Snow Haiku, for a visual as well as a haiku she wrote later that day.

Hands-on Snow Study

Fortunately, it snowed again on Sunday so my kiddos were able to get out and do the snow study as shown in the video. I hope others did as well. We didn’t bother to count the number of each type of snow crystal – but we did, in fact identify a number of them including: Hexagonal Plates, Stellar Plates, and Capped Columns. We thereafter spent time sketching each in our nature journals. We recorded the outdoor temperature was 20 degrees, no wind.

Submitted to Barb’s Winter Nature Study :: Snow 25th January 2009.