Change of State

statesWhen it snows we complain that we have to shovel the snow and clean it off our cars. We worry about driving conditions and are afraid we might fall on the ice that accompanies the snow. But if we wait a few days, the temperature will rise, and it will all melt and be gone. When it rains we complain that we are wet, that our roof is leaking or that there is flooding. But wait a few hours or days and the puddles dry up, the leak stops and the water recedes. And then when it doesn’t rain we complain that the plants are dying and the water table is low. But wait a few days and there will be rain.   This is all brought to us by the beauty of STATES OF MATTER.

Matter, and especially water changes state every second, every minute, every hour of every day on planet Earth.

Changes in state are all about energy, specifically heat energy. If we add energy (heat) to a solid, such as ice, we get water. If we keep adding more heat, we get a gas, water vapor. To reverse the process we reduce the amount of energy and the gas becomes liquid again, and then a solid if the temperature is cold enough.

My favorite phase changes are sublimation and deposition.  It is possible to go from a solid to a gas, this is called sublimation, and from a gas to a sold, this is called deposition.  An example of sublimation is dry ice (frozen carbon dioxide). When dry ice is placed at room temperature, it changes from a solid to a gas, and skips the liquid phase. An example of deposition is the  thin film of ice that forms on window during winter months.

For more information on changes of state of matter check out:

Snow Day!

snow-generic-writingAs a former teacher and mother of three, a prediction of snow was exciting and tense. Will it be enough to close schools? We watched the weather reports closely and learned about the best conditions for the maximum amount of snow to fall. We anticipated sleeping in and possibly going sledding.   We remember fondly times when the family went to the Art Museum area and had great times sledding on the hills. A snow day was magical to us so when it snows, my old thoughts kick in and I wish for copious amounts of snow.   Not for me anymore, I am retired and my children have children of their own, but I wished for snow anyway. Here is hoping that there is enough snow to keep you home at least once each winter!

Let’s look at a couple of things about snow:

Precipitation in the form of ice crystals is called snow.   Snow originates in the clouds when temperatures are below 32 degrees Fahrenheit (0 Celsius) and when water vapor in the atmosphere condenses directly into ice without becoming a liquid first (this is called deposition).   Additional water vapor from the air is absorbed and frozen on the ice crystal from the surrounding air and it grows into a snow crystal or snow pellet and falls to Earth.

I was reminded of something I must have heard over 50 years ago when I was a child growing up in Chicago, a place that has lots of snow.  I remember hearing that the Eskimos have “over 50 words for types of snow.”

This kind of linguistic phenomenon makes sense.   Language evolves to suit the ideas and needs that are crucial to the lives of the speakers. People who live with snow and ice all the time need to know things like whether the ice is fit to walk on or whether a person will sink through it.   Scientists and linguists say humans speak various tongues not to make it difficult for all of us, but to express their experiences in the jungle or in the desert, or in the cold and ice.

Anthropologist Frank Boas is credited for first citing that there are lots of words to describe snow when he was traveling though Baffin the 188s. There has been a lot of academic discussion as to whether his statement is true, but it seems as the controversy has been settled if you look at the idea of polysynthesis.  Polysynthesis is the formation of a word by the combination of several simple words. Many of the languages spoken by people in the far north combine many suffixes to make various words.

“The Eskimoan language group uses an extraordinary system of multiple, recursively addable derivational suffixes for word formation called postbases. The list of snow-referring roots to stick them on isn’t that long: qani- for a snowflake, api- for snow considered as stuff lying on the ground and covering things up, a root meaning “slush,” a root meaning “blizzard,” a root meaning “drift,” and a few others—very roughly the same number of roots as in English. Nonetheless, the number of distinct words you can “derive from them is not 50, or 150, or 1500, or a million, but simply unbounded. Only stamina sets a limit.”

For more information on language and the controversy about snow words check out these sites:

Twinkle Twinkle Little Planet


January 4, 2017, 5:30pm, clear skies, Philadelphia, Pa.

The moon was in its first quarter and shining brilliantly on us as I walked with my 2 1/2 year old granddaughter down the street. Her parents must have taught her to look up at the sky (as we all should) and she told me, “Look grandma,the moon and a star!” As we walked, she said it over and over again but then started saying, “Look grandma it’s the moon and a planet!” I recall telling her mother, my daughter, that the first star you see at night may not always be a star.

A star is a fixed luminous point in the night sky that is a large, remote incandescent body like the sun. Stars are so far away that the light we see may have travelled for millions of years before it reaches our eyes.

But a planet is a celestial body moving in an elliptical orbit around a star that reflects light from that star.

Sometimes, we can see Venus as the first “star” at night. She twinkles like a star because light is being reflected off her thick clouds and because Venus is relatively close to earth.   Venus can often be seen within a few hours after sunset or before sunrise as the brightest object in the sky other than the moon.

The other planet we sometimes see first in the sky is Jupiter. It also reflects light that makes it appear to twinkle like a star.

If you do see a star, it will be Arcturus, the first star in the Big Dipper. It will appear overhead in the Western Hemisphere and be slightly reddish.

Star light, star bright,

First star I see tonight,

I wish I may, I wish I might,

Have this wish I wish tonight.

It makes me wonder then, if we chant this children’s poem are we really wishing to Venus, or Jupiter (planets) or to Arcturus?

Walden Pond

imgresOn a recent trip to Boston, I found myself with a free day and no specific plans. Someone suggested a trip to Concord, Massachusetts and Walden Pond.

It’s been decades since I first learned about Henry David Thoreau and his two years in the woods.   How exciting it was to visit the area where he wrote Walden in 1854.

In addition to being known as a philosopher, writer and abolitionist, Thoreau is considered one of the first environmentalists with his many philosophical contributions to the way we view nature.   Thoreau was interested in people’s relationship with nature and studied this by living close to nature in a simple life. He published his experiences in the book Walden that argues that people should become intimately close to nature.   He felt that the physical environment inspires us. He wrote in his poem “Walking”: “I wish to speak a word for Nature, for absolute freedom and wilderness”

Fast forward to modern times and think about the book “Last Child in the Woods” by Richard Louv, where he states that humans, and especially children, are spending less and less time outdoors.   Louv contends that lack of being outdoors might be contributing to behavior and attention deficit disorders. Could Thoreau ever have imagined the electronic devices that draw children to be indoors? Could he even consider the fears parents often have of letting their children run free outside?

Consider an afternoon hike in the park or building in the outdoors into your daily routine.    Here are a few reasons you should go outside

  • Improved short term memory
  • Restored mental energy
  • Stress relief
  • Improved concentration
  • Sharper thinking and creativity

Click here for more information on each suggestion.





iPraxis is a Philadelphia-based 501(c)(3) nonprofit organization where we create opportunities for low-income students by increasing their interest and exposure to science, technology, engineering, and mathematics (STEM) disciplines through inquiry and project based learning. We do this by bringing individuals with a STEM background (students, professionals, retirees, professors, and more) into these schools to mentor students on science fair projects, lead after-school clubs, give presentations, and simply make science fun and meaningful.

If you have a busy schedule and are unsure if you have the time, please note that there are many different ways to get involved with iPraxis, each with varying levels of commitment. So if you have any interest in volunteering and making a difference in the lives of Philadelphia’s youth, please contact Lonnie Affrime, Volunteer Director, at or 856-669-7937. We look forward to working with you and changing the face of science!


The Islands of Lake Erie

searchIn early October I visited Erie Pa. to sit on a panel about Climate Change at an event called the Community Resiliency Summit.  The summit was hosted at the Tom Ridge Environmental Center, which sits right on the edge of Lake Erie. I am a long time Philadelphia resident but I grew up in the Chicago area, with Lake Michigan practically on my doorstep.  Being near one of the Great Lakes for a few days was very exciting to me since I’ve never been to Lake Erie before.    I learned that during the summer months over 300,000 people visit Erie for their summer vacations.  I decided to delve deeper into the wonders of the fourth largest of the Great Lakes, and the tenth largest lake on Earth.

The water provided by Lake Erie for waterborne commerce, navigation, manufacturing, and power production has led to intensive industrial development along its shore, but the basin’s moderate temperatures have also encouraged recreation and agriculture.  Lake Erie is the warmest and most biologically productive of the Great Lakes, and the Lake Erie walleye fishery is widely considered the best in the world.   ISLANDS What I found fascinating is that there are about 37 islands in Lake Erie, about 19 of them inhabited to some extent.   Most of the islands are officially in Ohio, but some are part of Ontario Canada, with only one actually being part of Pennsylvania.  Some, such as Presque Island, the only Pennsylvania “island”, are former islands and now are actually peninsulas with natural forest areas and state parks.   Others have small populations such as Pelee Island, population 171 people, (an important flyway for migrating birds) or south Bass Island with its 631 residents.  Populations on some islands swell in the summer months.  Other islands such as East Sister Island are small, with very little besides thousands of birds.   A few are privately owned such as Mouse Island (owned by the family of former President Rutherford Hayes), and one, such as Kafralu is man made. I really enjoyed visiting Erie PA., but I’m not so sure I’d encourage travel there in December.  The winters there can be fierce.   It’s a 6½-hour drive (404 miles from Philadelphia to Erie) but I think it could be worth the trip in the summertime.  (Amtrak goes to Erie.  You might try taking the train).


I’m pleased to share that I am on the planning committee for the National Science Teachers Association’s 2015 Area Conference on Science Education in Philadelphia, Pa, November 12-14, at the Pennsylvania Convention Center.  Please join me as we explore ideas and practices that enhance teaching and learning driven by the Next Generation Science Standards.  Learn more bout the conference at: