Here are some more random questions we've received from visitors to our website or our exhibits.
Q: Why is the Earth round? I thought it was flat.
A: Nope, the Earth is round. Not perfectly round, though. Planets like Earth are round due to gravity. Gravity pulls with equal strength in all directions, so gravity shapes the planet into a sphere. But, since the Earth rotates, the rotation adds centrifugal effects, which result in the Earth bulging slightly at the equator and flatten slightly at its poles.
Because of these centrifugal effects, the distance from the center of the earth to the surface of the earth is about 0.33% shorter at the poles compared to the equator.
Q: How does gravity work?
A: Gravity is one of the universal forces of nature, and is the tendency of objects with mass to accelerate toward each other. Newton's law of universal gravitation states that each particle of matter attracts every other particle with a force which is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.
More simply, everything that has mass has gravity, and the larger the mass, the stronger the gravity. Earth has stronger gravity than the moon because the mass of the Earth is greater than the mass of the moon.
Q: What is zero gravity?
A: Lots of gravity related questions! Zero gravity, or weightlessness, is best termed microgravity. Astronauts floating in space are not actually weightless, or in zero gravity, because the Earth's gravity is holding them and everything in the spaceship they are in, in orbit. They are actually in a state of free-fall, much like jumping from an airplane except that you are moving so fast horizontally that, as you fall, you never touch the ground because the Earth curves away from you.
Think about it this way. Considering what we learned about gravity above, if you stood on a bathroom scale and then somehow opened some trap doors that dropped both you (still standing on the scale) and the scale out of a plane, both you and the scale would be pulled down equally by gravity. You would not push down on the scale and therefore, your weight would read zero.
Q: Why is the sky blue?
A: Sunlight is scattered across the Earth's atmosphere by a process called "diffused sky radiation". The sky is blue because much more short-wave radiation (blue light) is scattered across the sky than long-wave radiation (red light). Check out this website that explains more about this, and also why the sky appears red during sunsets.
Q: How come the Science Museum you only teach one side of the story? What I mean by this is that not everyone believes in evolution, and you only talk about that side of the story. Why don't you have exhibits on theories other than evolution such as intelligent design?
A: It's in our name. We're The Science Museum of Minnesota. We represent and teach science in our exhibits and programs. We're not saying that there are not other ideas or beliefs out there (intelligent design is not a scientific theory, rather a religious belief), and we respect others and their beliefs. However, as an organization that teaches science, we practice and encourage the teaching of evolution as fundamental to the teaching of sound science and critical thinking. If we were to compromise the scientific explanations of evolution or permitted unscientific alternative explanations into our exhibits or our programs, we would be misrepresenting the principles of science. Here is the Science Museum of Minnesota's official position on evolution.
Q: Do you like pie?
A: Yes. I especially like Key Lime pie.
Gunther von Hagens’ BODY WORLDS exhibition provokes intrigue and questions about the scientific, cultural, and ethical aspects of anatomy and the preservation of human specimens, particularly in a public display.
Please join University of Minnesota experts for a FREE community forum series.
The Body on Display: Controversies and Conversations
Wednesday, June 28
Anatomy: Why We Dissect
Ken Roberts, Program in Human Anatomy Education, John Eyler, Program in the History of Medicine, and Dave Lee, Anatomy Bequest Program
Thursday, July 6
Boundaries and Bodies: Cultural and Religious Perspectives
Mary Faith Marshall, Center for Medical Humanities
Wednesday, July 12
Anatomy as Art, Art as Anatomy
Lyndel King, Weisman Art Museum, and John Eyler, Program in the History of Medicine
Wednesday, July 19
Stiff Morality: The Ethics of Using Bodies
Jeff Kahn, Center for Bioethics, will lead a panel discussion
Admission is free, but space is limited. Reservations for each session required.
To register, visit the University of Minnesota’s Academic Heath Center web page for the forums.
Location: Weisman Art Museum
333 East River Parkway, on the University of Minnesota campus.
7 - 8:30 p.m.
Light refreshments beginning at 6:30 p.m.
Parking is available for an hourly rate in the museum’s garage.
Questions? Call (612) 624-5100.
Today's Pioneer Press contains a letter to the editor from Ms. Sheila Steiner, of River Falls, Wisconsin. She writes:
"Would an anatomist in the U.S. have been allowed to skin a human body and fill it with plastic, pose it, and put it on display for a viewer fee simply because prior permission had been granted by the now deceased?
I cannot help but wonder how those who knew the living person think and feel about having their former loved one plasticized and on display.
It is reminiscent of an exhibit in Mexico where corpses were taken from graves and displayed to show how they had been preserved through minerals in the Earth.
It deeply troubles and saddens me to know that we have lost respect for the living as well as the dead. And we explain our unethical behavior as "an incredible learning opportunity".
Please skip the Body Worlds exhibit. Use your 20 dollars to feed the hungry or to buy a good anatomy book for a school."
Steiner's is a perfectly legitimate opinion, but what do you think? Whether you're here in the museum, and you've actually seen the exhibit, or you're visiting via the Internet, we want to know what you're thinking and feeling about the Body Worlds exhibit.
Did you find it gross? Beautiful? Disturbing? Fascinating? Moving? A little of each? Tell us about it.
Want to discuss the ethics of it? During the run of the exhibit, we're featuring four experts from our Advisory Committee (a Catholic theologian, a Hmong physician, a medical ethicist, and a body donation program director) to help answer questions and provide perspectives. Paul Wojda, a theology professor at St. Thomas University, is the first in this series. Ask him your questions!
Why not consider becoming a bird-bander or net runner at Lee and Rose Warner Nature Center? Join us for a Bird-Banding Volunteer Open House! Learn about this special volunteer program at Warner in person and see if it's for you. Banders are responsible for setting up mist-nets, regularly checking them to carefully remove ensnared birds, taking nets down and assisting in the bird-banding process. Typically, a Warner “primary bander” delivers a 30-minute program on banding to school program groups while banding captured birds. Net runners assist with bird retrieval and data entry. A love of birds, the outside, and being around children is useful. No banding experience is necessary, but a willingness to learn and ability to hike through the woods is required.
Today was Earth Day. Did you celebrate?
Here are some Earth Day resources:
This is a kids' Earth Day site. You can play games, download a coloring book, crafts, or recipes, adopt a rainforest animal, and learn the history of Earth Day.
Visit the US Government's Earth Day portal. It lists environmental highlights, suggestions for how you can make a difference, and volunteer opportunities. It also has teacher resources.
The Yahoo! web portal has a list of 10 easy things you can do to slow climate change.
Here in Minnesota the days are finally getting longer and we’re getting more daylight each day. Residents in the Austrian town of Rattenberg are also grateful for the return of spring’s longer days. You see, Rattenberg gets no sunlight at all from late fall to mid-winter. The town was founded some 700 years ago and was uniquely situated between the Inn River and the Rat Mountains for protection from bandits. However, the same mountains that protected the town from bandits also leave it in shadows from November to mid-February as the sun never rises far enough on the horizon to shine directly onto it.
People in Minnesota sometimes get a little discomforted during the shorter days, some even suffer from Seasonal Affective Disorder (SAD), which is a mood disorder associated with depression episodes related to seasonal variations of light. I can’t imagine what it would like to live in a shadow for over three months of the year – knowing that there is sun, but that it is blocked by a nearby mountain. Residents of Rattenberg have been leaving the town for sunnier locations and the town’s population is declining.
To help its residents get some light during the winter the town is working with Bartenbach Light Laboratory to install 15 heliostats (giant mirrors that track the movement of the sun) about a quarter of a mile outside the town – and beyond the reach of the mountain’s shadow. The heliostats will reflect the sunlight to a giant mirror covered tower in the city, which in turn will reflect the light to small mirrors on buildings throughout the town, which then transfers the light to the streets. The heliostats and mirrors will be installed this August at a cost of around $2 million. The hope is that tourists, who frequent the town in the summer to purchase blown glass artwork the town is famous for, will now visit year-round, and that residents will no longer look to leave for sunnier locations to live.
Have you had your wisdom teeth pulled? I have. And they were impacted. Not on my list of all time favorite memories — in fact, having teeth pulled is one of my least favorite things to do.
Apparently, it was also not a favorite thing to do for the "Magdalenian Girl" (also known as the Cap Blanc skeleton), a nearly complete 13,000- to 15,000-year-old skeleton excavated in France in 1911and acquired by The Field Museum in 1926. To be fair, the pulling of wisdom teeth may not have been possible for her, but it turns out that her wisdom teeth are proving very valuable.
It had been previously believed that the Magdalenian Girl was under the age of 18 at the time of her death because her wisdom teeth had not grown in, which usually happens between the ages of 18 and 22 (I was 20). But after a new analysis of the skull, scientists now believe the Magdalenian Girl was actually between the ages of 25 and 35 when she died. This new theory has come about after looking at new digital X-rays (such as the one pictured) which show that the Magdalenian Girl's wisdom teeth were impacted.
So, why is that a big deal? Impacted wisdom teeth are thought to be the result of dietary changes that occurred in past human cultures. It is believed that impacted wisdom teeth were not common during the stone ages because the food that people ate at that time required them to chew more and chew more vigorously. This more intense chewing would have resulted in increased jawbone growth, which in turn creates more room for the wisdom teeth to grow in. When the diet changed to foods that required less forceful chewing the jawbone was not stimulated to grow as much, making less room for wisdom teeth when the time came for them to grow in. So, the fact that Magdalenian Girl has impacted wisdom teeth tells scientists that the diet of her time period would have already changed.
The skeleton of the Magdalenian Girl, the most complete Upper Paleolithic skeleton available for study in North America, is a part of the new permanent exhibition at the Field Museum called Evolving Planet. If you happen to see the exhibition, make sure you also check out the Kristi Curry Rogers' Rapetosaurus krausei also on display in the exhibition. Kristi is the Science Museum of Minnesota's Curator of Paleontology.
James Kakalios, a current "Scientist on the Spot", will give a presentation about his book, The Physics of Superheroes, on Thursday, February 16 at 7:00pm at the Hamline Midway Branch Library. For more information, contact: The Friends of the Saint Paul Public Library at 651/222-3242 or visit www.thefriends.org. His appearance is part of pretty neat line up of authors.
Another series of presentations that sounds pretty interesting is called "Dying: A Guide for Beginners" and take place at the Merriam Park Branch Library a bunch of times between now and March 28.
The University of Witwatersrand in Johannesburg South Africa has long been known for its impressive discoveries related to human evolution. Discoveries from Witwatersrand related to human evolution typically emphasized the importance of not only Africa but South Africa in the development of early man. Many of the more famous discoveries related to Paleoanthropology or the study of human evolution come from East Africa — where researchers have discovered, and continue to discover, some of the best evidence for human origins in Africa. Researchers further south, however, continued to argue that fossil discoveries from South Africa should not be discounted from the developing picture of the history of early man.
One of the most significant South African discoveries was the Taung child, which was discovered in 1924 and was given its name when the first researchers to examine the fossil concluded that the specimen was so small because it was a child. This week, researchers from Witwatersrand are announcing that the Taung child could have been killed by a large bird. Yahoo News is reporting that by studying the hunting abilities of modern eagles in West Africa, researchers determined what signs would be left behind on a skull of an animal that was killed by a predatory bird. Armed with this new knowledge, Physical Anthropologists reexamined the Taung child and found traces of cuts behind the eye sockets. Even though the specimen has surely been examined hundreds of times since its discovery, nobody had really noticed the marks before.
Discoveries like this one prove that new discoveries and interpretations can be made by simply reexamining old discoveries with a fresh pair of eyes. No pun intended.
The journal Science has named a few studies that followed evolution in action--in influenza viruses, chimpanzees, and stickleback fish--"Breakthroughs of the Year."
Science Blog explains the significance of these studies, and the rest of the "top ten" science achivements of the year.