Monthly Archives: April 2017

Put This Date on Your Calendar: August 21, 2017

A total solar eclipse will be visible in South Carolina on Monday, August 21, 2017. 
Neil DeGrasse Tyson, the director of the Hayden Planetarium at the Rose Center for Earth and Spance in New York tells us to put it on our bucket lists because it is both rare and spectacular. 

The moon’s shadow will sweep along a 70 mile wide path at 1.5 times the speed of sound, providing witnesses in that path with just about 2 minutes of spectacle. Those not in the path will see only a partial eclipse.

For those in the path “It will be like having a 360-degree sunset all around you says NASA’s Lika Guthathakurta. ‘Stars appear. The temperature drops. You can actually hear chirping of grasshoppers. So, animals actually naturally go back to their nocturnal behavior.'” 

Jay Pasachoff, a Williams College astronomer and eclipse expert will travel from his home in Massachusetts to a location along the path because “It’s a tremendous opportunity… to see the universe change around you.” (

For those of us who are not astronomers or eclipse experts this rare event is a prod to our curiousity about how the universe, in this case the some of the workings of sun, moon, and Earth.

The textbook model of a solar eclipse is pretty simple.

A solar eclipse happens when the moon passes between Earth and the sun during the new moon phase. A lunar eclipse happens when the moon is behnd Earth during the full moon phase. 

But the simple explanation leaves two interesting questions unanswered, as “why isn’t there an eclipse of the sun each month when the new moon passes between Earth and sun?” and “Why does the path of the eclipse move from west to east?”

To fix the model, we need to add some important facts.

First, moon’s orbit is not perfectly round which means that at its perigee (or lowest point in the orbit) is about 225,000 miles from Earth and at its apogee (or highest point in the orbit) is 251,900 miles from Earth. Its mean distance from Earth is 239,000 miles.

Second, the moon’s orbit is titled by 5 degrees relative to Earth’s orbital plane. To visualize this imagine that you have two rings, a larger (representing Earth’s orbital plane as it revolves around the sun) and a smaller (representing the moon’s as it orbits Earth). If you put the smaller ring onto the larger ring and tilt it slightly (about 5 degrees) you will see that there are only two points on the ring at which the two rings are in the same plane. 

As the moon orbits Earth, (following the path of the smaller ring) it will ascend relative to Earth’s orbital plane for half of its orbit and decline for the other half.

If new moon occurs when the moon is at the top of its orbit, as it moves between Earth and the sun the moon’s shadow will miss Earth high. It it’s at the bottom of the orbit, the shadow will miss low. 

There are two points on the orbit when it crosses what is called the ecliptic, or the plane of Earth’s orbit around the sun called the “lunar nodes.” The line of the nodes align with the Sun every 346.6 days (= an Eclipse Year).

Now, our model is more complete and we can derive from it that the following conditions must be met in order to have a total eclipse of the Sun:

The moon is in the phase called new moon because it is then that it passes between Earth and Sun.

The moon is at the lunar node and thus in the same orbital plane as Earth and Sun.

Moon is relatively closer to Earth (>236,000 miles) because its shadow (umbra) will only extend 236,000 miles. If the moon is too far away, its shadow won’t fall on Earth’s surface.

All three conditions will be met on August 21, 2017, with moon’s shadow falling on the U.S. beginning in Oregon and ending in Charleston, South Carolina.

We are accustomed to thinking of the sun and moon rising in the east and moving westward. So why does the path of totality move from west to east, from Oregon to South Carolina?

You can work this out for yourself by simply changing your point of view from Earth to imagine that you that you can travel far enough into space so that you can see the sun, earth and moon in one view. 

You can see the earth rotating on its axis counterclockwise and the moon, orbiting around it, moving above it also moving counterclockwise.

As it moves across Earth, you can see its shadow moving counterclockwise, towards the east from the west.

This also helps to explain why the shadow moves so very quickly, giving each obsever only about two minutes of spectacle. 

According to NASA the moon orbits toward the east at about 3,400 km/hour while Earth rotates to the east at 1,670 km/hour near the equator. The moon’s shadow is therefore moving at 3,400 – 1,670 km/hr = 1730 km/hr.

According the NASA, you would need to travel at Mach 1.5 to keep up with the moon’s shadow!

While our model for understanding a solar eclipse is complete, a solar eclipse makes it possible to study another phenomenon that is one of astronomy’s great mysteries. 

When the moon’s shadow completely blocks the Sun, the solar corona, a beautiful aura will surround the moon, revealing it for scientific study. The solar corona is composed of plasma (the fourth state of matter). Mysteriously, the corona is much hotter than the sun’s surface. How can something farther from the source of heat be hotter than material at the source?

We will examine this mystery in a future blog.


There are many, many resources for understanding eclipses: The following are just a few. In addition there are many apps that allow for interactive study of solar and celestial events.

Women in Science: Komal Dadlani: Making Available Science Available to All

Robert Hooke engineered a better microscope and an accurate clock.
Isaac Newton is credited with the invention of the reflecting telescope.
Robert Boyle’s experiments required the development of a vacuum pump.
The practice of observational science demands good instruments; how can you tell how fast the ball rolls without a way to accurately count the seconds?
Four centuries of invention have supplied scientists with a large array of technologies that make modern scientific investigation possible.
Unfortunately, these technologies are mostly available at the high end and that unfortunately also means, “not in schools.”
This doesn’t mean that the technology for schools is not available, but it is expensive, especially for schools that serve economically challenged communities.
Komal Dadlani who was born in Chile, where only 2 out of every ten schools has a science lab, was fortunate enough to graduate from one that did and thus was able to go to university and graduate with a master’s degree in biochemistry.
To share her good fortune, she searched for a way to provide the opportunity for a science education with others.
Her “ah ha!” moment came with the realization that while schools don’t have well-equipped labs, large proportions (between one-third to more than half) of their students do have smart phones.
The development of the smartphone, first with the iPhone from Apple and then from a host of vendors has meant that technologies that were once available only to high-end users like NASA are integrated into smartphones.
Magnetometers make the phone’s compass possible; promixity sensors signal the phone’s operating system when the phone is placed next to the ear to take or make a phone call. Quite ordinary smartphones have gyroscopes, photodetectors, acceleromters, barometers, thermometers, sensors that make them “smart.”
So while K-12 schools that do not have laboratory equipiment, these schools could take advantage of the smartphones that many of their students carry with them daily?
Tapping the power of the smartphone sensors was how Ms Dadlani and colleagues solved the problem.
Komal and her team is now in the U.S. in the process of creating a new business which they call Lab4U.
“‘We leverage these senors and design experiments,’ she explains'” in an April 7 article in People magazine.
They have release two apps (both available for both IOS and Android), one for physics and one for chemistry.
One (which I have installed on my relatively old iPhone 5) is Lab4Physics.
Once you create a free account, the user has accesss to camera, the accelerometer, the sonometer and the speedometer that can capture and graph data. You can “play physics” and do experiments in movement, force and energy, and sounds.
There is also Lab4Chemistry uses software to transform your smarphone into a colorimeter that allows for the calculation of concentrations of chemical solutions and to use spectrophotometry.
The company is still a startup and not established as yet but it demonstrates a key idea that has driven STEM for four centuries: “it’s not strength. It’s not intelligence. It’s ADAPTABILITY TO CHANGE” that makes new things possible. (
Crunch Base: Komal Dadlani. Retrieved from


Toyota Mothers of Invention: Retrieved from

You and Your Many Clocks

What is it about the Monday following the switch from standard to daylight saving time?

There is a predictable pattern of bad things happening after our “spring forward”: a spike in heart attacks, strokes, and traffic accidents, and even noticeable reduction in worker productivity that are connected to the loss of sleep because “even small changes in sleep could have detrimental effects” including full-blown illnesses.” (Reuters, 2017)

This is because our bodily processes depend upon their precise synchronization with the natural cycles of light and darkness to work properly. Loss of an hour of sleep can disrupt synchronization so that a major disruption can cause serious illness. (Friedman, 2017)

As far back as the 1960s, a German psychiatrist had heard about a woman who was apparently able to keep the demons of her depression at bay by nighttime bicycle rides.  It appeared that going without sleep could “reset” some aspect of the woman’s functioning and relieve the symptoms of depression.

He tested his hunch on a group of his depressed patients by keeping them awake for a single night as a substitute for the nocturnal bicycle ride.

The next day, he was struck by how most of the patients exhibited cheerful optimism rather than their habitual glum weariness.

In another example, physicians in a Milan hospital housing a ward of patients suffering from bi-polar disorder were struck by the fact that patients who occupied rooms that faced east were discharged earlier than those in rooms that faced west. In their reflections about why this was so, the physicians wondered whether the early sun had some therapeutic effect on the patients. (Friedman, 2017)

From ancient times people have observed the effect of day and night on living things, such as flowers opening and closing with sunrise and sunset.

Such observations led 13th century Chinese medical practitioners to connect the cycles of day and night with health and illness.

The actual mechanisms that connect the diurnal cycles to life processes were not discovered until investigators were able to examine biological processes at the molecular level.

The relationship between the organism and the alternation of light and dark based on the solar day is called the circadian cycle, (circa-around; diem-day).

There is now even a whole field of circadian biology whose research has opened new understandings about how we and our environment interact.

The patterns of daylight and darkness are not simply backdrop to our daily lives but  are deeply embedded into our personal biology. In fact, our circadian cycle is tied to the solar day; “it is influenced and kept in check by the daylight cycle.” (Friedman, 2017)

When it gets dark at night a communication channel to the pineal gland is opened activating proteins in the pineal gland that begin to produce melatonin, a hormone that regulates other hormones and is known to help maintain the body’s circadian rhythm. A number of things start to happen, various hormones are activated by the melatonin: your body temperature begins to drop, your kidneys reduce the rate at which they produce urine, and you begin to feel sleepy. (See Melatonin )

Based on this information, it is not difficult to see why the “spring forward”  weekend messes with your circadian cycle. When your alarm goes off on Monday it’s as if you have flown across an entire time zone. You effectively went to sleep in Chicago and woke up in New York, a difference of a whole time zone.  Worse it is probably still be dark,  further confusing your synchronization with the solar day.

Other activities can cause you to get out of sync.

Your television and computer screens emit short-wave length (blue) light that can make it harder to fall asleep.

Shift work especially when the worker is on sometimes during days and then must switch to night work plays havoc and can result in insomnia and even depression. (Moon et al., 2015)

Jet-lag with its fatigue, malaise, poor concentration, and mood changes is the result of flying from one city to another across multiple time zones, leaving your circadian cycle stuck in the time zone you left.  (Friedman, 2017)

So feeling grumpy on the Monday after springing forward is not trivial. The usually temporary malaise is a symptom that several of the many biological clocks that “are believed to exist at all levels of life and play a key role in the maintenance of physiological and behavioral processes” are out of sync.

Chronic disruption of one’s circadian rhythm can cause sleep problems which can adversely affect health. According to research a significant proportion of the adult population does not sleep well and night and has difficulty staying alert during the day…(Harrington, 2010) & (Ray and Reddy, 2016)

There are things you can do to help keep yourself in sync. For example, click here for tips on overcoming jet lag.


Friedman, R. A. (2017c). Yes, Your Sleep Schedule Can Make You Sick. New York Times. Retrieved from

Krishnan, H. C., & Lyons, L. C. (2015). Synchrony and desynchrony in circadian clocks: impacts on learning and memory. Learn Mem

Learning & Memory, 22(9), 426-437. doi:10.1101/lm.038877.115

Moon, H. J., Lee, S. H., Lee, H. S., Lee, K.-J., & Kim, J. J. (2015). The association between shift work and depression in hotel workers. Ann Occup Environ Med

Annals of Occupational and Environmental Medicine, 27, 29. doi:10.1186/s40557-015-0081-0

Ray, S., & Reddy, A. B. (2016). Cross‚Äêtalk between circadian clocks, sleep‚Äêwake cycles, and metabolic networks: Dispelling the darkness. Bioessays, 38(4), 394-405. doi:10.1002/bies.201500056

Reuters (2017) Hate daylight saving time? You may have a point, researchers say. Retrieved from

The Union Public Schools: Choosing to be Excellent

The Union Public Schools: Choosing to be Excellent

A school classroom, somewhere in Oklahoma:

The students in this class are to design and build a video game in which the player must guide a cow across a busy highway. A successful program will result in either the cow successfully crossing the road resulting in the player being rewarded with a hand clap while if the cow is hit, the feedback to the player is an “Aw.”

That this is a high school coding class would be a good guess but it is actually a class of first graders engaging in their school’s STEM for all curriculum that begins in kindergarten and continues through high school where the students design mobile apps and web pages, while tackling cybersecurity and artificial intelligence projects. (Kirp, 2017)

Although the vignette suggests an affluent district, it comes from the Union Public School District that hosts 16,000 K-12 students located on the economically challenged east side of Tulsa, Oklahoma. 70% of the students qualify for reduced lunch ( 65.5% white, 31.3% Hispanic, 14.9% AfricanAmerican, 7.9% multi-racial, 6.9% Asian, and 4.9% American Indian). (Union Public Schools Annual Report)

Among other challenges is the fact that 2,700 of the children are English Language Learners (ELL) representing 50 different languages. 

Oklahoma has not been generous in support of its schools, and thus Union has about one-third fewer dollars per student ($7,605) than the national average.

A teacher in Union with twenty years experience and a doctoral degree will earn a bit less  than $50,000 per year. For a comparison, Kirp notes that teacher with similar qualifications in Scarsdale, New York, would earn $120,000.

Despite its challenges Union does better than the national high school graduation average with an 88% graduation rate with 100% of those off to further education. The district’s accomplishments are the results of a decade of serious effort triggered by a meeting in which the superintendent reviewed by name a list of dropouts and was humiliated when none of the district principals were able to account for any of the kids.

Over the decade of rebuilding, the faculty and administration worked at making their schools responsive to the community’s children and youth. (Kirp, 2017)

In an affluent middle-class community, parents provide their children with an abundance of out of school activities: art and music lessons, visits to science museums, summer science camps, sports camps, academic tutoring and enrichment like SAT preparation courses.

In east Tulsa where most families are economically stressed, the Union schools have picked up the role filled by affluent middle class families by transforming themselves into “community schools” that provide enrichment activities for their students and their families by opening early, so parents can drop their children off on the way to work and staying open late and during summers. “They operate as neighborhood hubs, providing families with access to a health care clinic in the school or nearby; connecting parents to job-training opportunities; delivering clothing, food, furniture and bikes; and enabling teenage mothers to graduate by offering day care for their infants.” (Kirp, 2017).

Professor Kirp’s question “Who Needs Charters When You Have Schools Like These?” challenges the assumption that public schools are unable to meet the needs of students and their families.

The power of that assumption provides the rationale for the President’s 2018 budget recommendation that while cutting the federal Department of Education’s overall budget by $9 billion, there would be “an additional $1.4 billion into school choice programs.”

School choice is a policy, which is a tool that is used to accomplish a task, and policy “work best when its actually tailored to the task at hand.” (Williams, 2017)

School choice programs can be connected to equitable access and better outcomes for the traditionally underserved populations when they are well-crafted.

For example, Louisiana rebuilt its hurricane ravaged schools based on the creation of charter schools after Katrina.  A painful learning curve made it clear that the new system would not work without an aggresive accountability system that would ensure that unsuccessful charters were closed. The result is that New Orleans system of public charters is thriving.

Michigan invests heavily in charter schools. Its policies are based on the idea that the more charters the better, and accountability is weak.  The result is that “the unchecked growth of charters has created a glut of schools competing for some of the nation’s poorest students, enticing them to enroll with cash bonuses, laptops,…and bicycles…fighting so hard over students and the limited public dollars that follow them that no one thrives.”

State policy permits unsuccessful schools to shop around for new authorizing agencies and be back in business under a new name. (Zernike, 2016)

Instead of raising all schools the charter movement has resulted in “a total and complete collapse of education in this city,”  according to Scott Romney, a board member of the civic organization New Detroit. ( Zernike, 2016)


Kirp, David (2017). Who Needs Charters When You Have Schools Like These? New York Times, April 1, 2017 Retrieved from

Williams, Conor P. (2017). School choice is great… Washington Post, January 19, 2017. Retrieved from

Zernike, Kate (2016). A Sea of Charter Schools in Detroit Leaves Students Adrift. New York Times, June 28, 2016. Retrieved from


accountability, STEM, school choice, public schools, U.S. Department of Education, Louisiana, Michigan, vouchers, charter schools