Save The Date: GEMS on February 11, 2012!

We had a terrific time at the Girls Exploring Math and Science event last year on Saturday, February 19, 2011. The Museum was buzzing with lots of learning – songs about kinetic and potential energy, buzzing instruments made with straws, Popsicle sticks and rubber bands, and lots of “ah-hah” moments throughout the day!

We had a fabulous presenting sponsor in KBR and two of their engineers were our featured speakers, Rachel Amos and Elaine Jimenez. Rachel and Elaine shared with the GEMS attendees a bit about their careers in Mechanical Engineering with KBR, their education, some tips for aspiring young engineers and scientists, and even a little about what they loved about math and science as kids. Interactive booths were hosted throughout the building by students, girl scout troops and local organizations and companies - there was so much to learn everywhere you turned!

Girl Scout booths have just been accepted for GEMS 2012 and there are some exciting topics and new ideas I’m very excited to see.

We’re still accepting applications from School Groups for booths and if you’re just now considering hosting a booth with your friends or opening it up to your class for extra credit it’s time to get some brainstorming going!  

What is a topic you’d like to know more about? What have you recently learned that you would want to share with your peers?

Here are a few links to sites that might inspire you for your awesome GEMS booth! Applications for school booths can be found online here at the HMNS website.

The Library of Congress – Everyday Mysteries’s Zoom for kids  - this link is to the engineering section but they offer lots more if you click around

How Stuff Works - go ahead – ask how it works!

Penn State College of Agricultural Science – Food Science - so many cool things to explore!

I’m also including some fabulous outcomes provided by some of our super star 2011 presenters, the “Truth in Numbers” group and the Rice University Association for Women in Mathmatics both presented booths on the topic of statistics and asked visitors to participate in their experiments pulling samples and recording results!

We can’t wait to see what everyone comes up with for GEMS 2012!

Visitors were asked by the Rice University Association of Women in Mathmatics to open a funsize bag of M&M's candies and chart how many candies of each color were included.




Go Stargazing! December Edition

Jupiter is well placed for observing on December evenings. Face east at dusk and look for the brightest thing there—that’ll be Jupiter.

Venus has fully emerged from the Sun’s glare.

After Sunset (Moon & Venus & Jupiter)
Creative Commons License photo credit: scyllarides

Look for it low in the southwest at dusk. (Venus is slightly higher in the evening sky each night this month). We are still near the beginning of Venus’ apparition as evening star; it gets higher and easier to see for the rest of this year and is spectacular for about the first half of 2012.

Mars rises around midnight and is now high in the south at dawn. Although not nearly as bright as Venus or Jupiter, Mars has brightened enough to rival the brightest stars in the sky, and will keep brightening all winter as Earth approaches it.

Saturn remains in the morning sky this month.

Look low in the southeast at dawn, near the star Spica. (From the Big Dipper’s handle, arc to Arcturus and speed on to Spica).

The Summer Triangle sets in the west. Watch for the Great Square of Pegasus almost overhead at dusk now and in the west by Christmas. Facing north, you’ll see five stars in a distinct ‘M’ like shape—this is Cassiopeia, the Queen. Her stars are about as bright as those in the Big Dipper, and she is directly across the North Star from that Dipper. In late autumn, as the Big Dipper hugs the horizon and actually sets for us in Houston, Cassiopeia is high in the north. Taurus, the Bull rises in the east. Look for the Pleiades star cluster above reddish Aldebaran. Dazzling Orion, the Hunter rises shortly after dusk (by month’s end, it is already up at dusk). As Orion enters the evening sky, we transition from the relatively dim evening skies of autumn to the brilliant stars of winter.

Orion nebula: M42
Creative Commons License photo credit: Alessandro S. Alba

Moon Phases in December 2011:
First Quarter December 2, 3:52 am
Full December 10, 8:37 am
Last Quarter December 17, 6:48 pm
New December 24, 12:07 pm

The Full Moon of Saturday morning, December 10, enters the Earth’s shadow, causing a total lunar eclipse.

Unlike last year’s event, however, this eclipse heavily favors western observers in North America; we miss most of it here in Houston. However, the Moon does nick the edge of Earth’s umbra at 6:46 am that morning, when it is a scant three degrees above our horizon in Houston. If you have a northwest horizon utterly clear of trees or buildings, you might try to observe the very beginning of the eclipse before moonset.

At 11:30 pm on Wednesday, December 21, the Sun is directly overhead as seen from the Tropic of Capricorn, the farthest point south where this is possible. That makes December 21 the winter solstice, the date when the noon Sun is lowest in the sky, and when we have the fewest daylight hours of the year. However, the earliest sunset of the year here in Houston is not on the solstice, but approximately on December 2! That’s because the Earth speeds up on its orbit as it approaches perihelion (closest approach to the Sun) next month. This acceleration shifts sunrise, local noon, and sunset slightly later each day this month and next. The effect is smaller that that of the Sun taking a lower path across the sky, which normally dominates in causing earlier sunsets and later sunrises. But the Sun’s apparent path varies very little near the solstice itself, allowing the secondary effect of the Earth approaching the Sun to predominate. For most people, then, (those who witness sunset but sleep through sunrise), days will seem to lengthen throughout December, although they don’t really begin lengthening until December 21.

We are making improvements to the main telescope at George Observatory! Visitors on Saturday, December 10 and December 17 will find the 36-inch Gueymard telescope closed for repairs. Our 14-inch east dome telescope and 18-inch west dome telescope will still be open to the public, however, so we hope you’ll join us anyway! Also, Christmas Eve and New Year’s Eve fall on Saturday this year; the observatory will be closed on December 24 and 31.

Visit to see the Planetarium’s film Schedule.

On most clear Saturday nights at the George Observatory, you can hear me do live star tours on the observation deck with a green laser pointer. If you’re there, listen for my announcement.

A Short Biography of the Foucault Pendulum.

When you walk into the Wiess Energy Hall, the very first thing you see is our Foucault pendulum.

It is a metal ball suspended by a cable that swings back and forth encircled by pegs. Children and adults will run through the rest of the museum, reach the pendulum, and wait with baited breath to watch a peg topple. When one of the pegs finally falls, you can hear a cheer erupt from the area. It is one of the most memorable parts of the museum. As the pendulum swings, it moves clockwise knocking down pegs as the Earth turns. It swings back and forth, back and forth (you are getting sleepy).

Foucault Pendulum
Foucault Pendulum at the Houston Museum of Natural Science

It is interesting to sit around the pendulum and listen to people try to explain it.

Some will talk about how it is a clock.  Others will put the time between pegs being knocked down between 10 minutes and 1 hour.  Our pendulum knocks down a peg on an average of every fifteen minutes. While the pendulum looks like it rotates around the circle, it is the Earth that is rotating and the pendulum that just swings. The pendulum is a visualization of a rotating Earth. To describe it in a different way, T = 24/sin q where T equals the amount of time to make one complete revolution and q is the latitude of the pendulum. At least that’s what Foucault said.

Star TrailsCreative Commons License photo credit: monkeymanforever

Leon Foucault was born in Paris (France, not Texas) on September 18, 1819.

As a young boy he did not show an inclination towards science or study.  In fact his teacher considered him lazy because he did not turn in his work. He did, however, enjoy building mechanical devices, such as a small steam engine and a telegraph, and tinkering.  He entered medical school to become a surgeon, but found that he fainted at the sight of blood.  Instead of becoming a blindfolded surgeon, he switched to physics. 

At the age of 25, not having learnt anything at school nor from book, enthusiastic about science but not about study, Léon Foucault took on the task of making the work of scientists understandable to the public and of passing judgment on the value to the work of leading men of science – J Bertrand, Éloge historique de Léon Foucault.

Foucault proved his worth in being able to take mathematical proofs and construct a mechanical proof, his pendulum being one of those.

He also constructed a device to prove that light moves slower through water than air. The mathematics describing the proof had been around for over a decade, but Foucault was the first to prove that it worked. His first pendulum on public display opened on February 3, 1851 in the Paris Observatory (again France, not Texas). Instead of knocking down pins as the pendulum moved, the first Foucault pendulum drew in sand.  He also invented the gyroscope, which stays in place as the Erath moves around it. This invention has proved essential for planes, space craft, and even the Hubble Telescope.  

Hubble Space Telescope
Creative Commons License photo credit: NASA Goddard Photo and Video

After he came to power, Napoleon III, an amateur scientist, created a job for Foucault at the newly named Imperial Observatory. There, Foucault developed his knife edge test to measure the conic shape of mirrors. This led to a more constant quality of lenses for use in telescopes.  He died on February 11, 1868 from multiple sclerosis.  His legacy lives on today.  He has an asteroid named in his honor. But he is honored around the world by his plethora of pedula that swing to and fro, showing people that the Earth keeps on spinning.

The Celestial Sea

As you look up into a November sky right at nightfall, you may notice fewer bright stars than at other times of year. No, it’s not just the glare from Houston hiding most of the stars from view–there really are fewer bright stars in the November evening sky than in, say, February or August. To understand why, you need to understand the shape of our galaxy itself.

death cab for cutie:I'll follow you into the dark
Creative Commons License photo credit: visualpanic

Our galaxy, the Milky Way, is a barred spiral galaxy.

Evidence indicates that the Milky Way, like many large galaxies, has a massive black hole at its center. A radio source designated Sagittarius A* could be the black hole itself. (The asterisk is part of the name, which is “Sagittarius-A-star”). Surrounding this black hole is a central bulge where older (and thus redder) stars predominate.  The Bulge of our galaxy is not fully spherical but instead forms a bar a few thousand light years long.  Branching out from this bulge are spiral arms which contain younger (bluer) stars and dust clouds out of which brand new stars form.  Our solar system is about 26,000 light-years from the center to the edge, on the inside edge of the Orion Arm.  The Orion Arm, in turn, is but a spur of the much longer Perseus Arm.  The Milky Way is quite flat–over 100,000 light years wide but only 1,000 light years thick.

The flatness of the galaxy means that most of its stars are near a certain plane in space.  Of course, the galaxy is much thicker than our solar system, so we see our stellar neighbors suurounding us on all sides.  The rest of the galaxy, extending off into the distance, appears to us as a hazy blur in the background, with individual stars (those fairly close to us) in the foreground.  That hazy blur looked like spilled milk to the ancient Greeks, thus the name ‘Milky Way.’  We see more stars near that plane than far from it.

What does this have to do with the dimness of a late November sky at dusk?

Imagine observing our flat galaxy from our vantage point on Earth. When we face into the galactic plane, we see more bright stars, because there are more stars in that direction.  When we face above or below that plane, we see fewer bright stars.

Face west at dusk in late November and early December, and you’ll notice an enormous triangle of three bright stars, all bright enough to appear even in skies lit by Houston.  These stars from the Summer Triangle, so called because it is up all night long from June through mid-August.  This Triangle is also directly in the plane of the Milky Way.  The constellation Sagittarius, which marks the center of the Galaxy, sets just after the Sun this time of year.  Therefore, if you trace a path approximately from the  point of sunset through the Summer Triangle, over to five stars in an ‘m’ shape in the North (that would be Cassiopeia, the Queen), and then over to the northeastern horizon.  This is the plane of the Milky Way across late autumn skies at dusk .

Turn to the south, and you face below the galactic plane (as we’ve arbitrarily defined ‘above’ and ‘below’).  Here is a vast region of sky almost void of bright stars.  One exception is Fomalhaut, low in the southeast at dusk tonight.  Also, Houstonians with a very clear southern horizon can see Achernar very, very low in the south on December evenings.  But that’s about it.  There are many fewer bright stars in this direction than towards the Summer Triangle.  By the way, the brilliant object in the east at dusk tonight, and high in the southeast as dusk in December, is Jupiter. It doesn’t count as a bright star for this sector of the sky.

The Celestial Sea

When ancient Mesopotamians looked up into the dim skies you see at dusk tonight, they imagined the Persian Gulf south of them extended up into the sky, forming a ‘Celestial Sea’.  They therefore placed many water-themed constellations in this part of the sky.  Zodiacal constellations here include Pisces, the Fish, and Aquarius, the Water-Carrier.  Even Capricornus, the Goat, has the tail of a fish because he originally represented Ea, the ancient Babylonian god of the waters.  Under Pisces is the sea monster Cetus, while Piscis Austrinus, the Southern Fish, drinks the water that Aquarius pours.  Eridanus, the River, rises in the southeast, flowing from Orion’s foot into this vast ‘sea.’

Creative Commons License photo credit: paul (dex)

Contrast this vast, dim region with the much brighter swath of stars that rises in the east later this evening (9-10 pm in late November, earlier in December).  This region of sky includes the brilliant pattern Orion, the Hunter, as well as Sirius, the brightest star we ever see at night.    When these stars rise, we are beginning to face back into the plane of our galaxy, this time looking into our own arm of galaxy at the stars right ‘behind’ the Sun.  (This is why our arm of the Milky Way is called the Orion Arm.)  Winter evening skies are much brighter than those of late autumn.