Stories tagged Odds and Ends

Aug
09
2006

Q: Why do people blink?

A: People blink because the eye needs to be kept clean and moist. Every time you blink your eyelid coats the eye with fluids that keep your eyes moist and that flush away gunk. Blinking also helps prevent gunk from entering your eyes in the first place – lowering the lids and eyelashes forms a barrier that is hard for gunk to penetrate. Interestingly, you bink less when you are concentrating on something (like driving or surfing the internet).

Q: How tall can a willow tree be when they are full grown?

A: That depends on what species of willow tree you are referring to – there are lots. The White Willow can reach heights up to 100 feet, while the Artic Willow grows to less than a foot in height!

Space shuttle bathroom: A typical space shuttle bathroom.  Image courtesy NASA.
Space shuttle bathroom: A typical space shuttle bathroom. Image courtesy NASA.
Q: How do astronauts go to the bathroom in space?

A: Typically, there are toilets similar in function to toilets on Earth, but they use air suction instead of water to make the waste go where they want it to, since there is no gravity. Solid wastes are compressed and stored on-board, and then removed after returning to Earth. Waste water is vented to space, although future systems may be able to recycle it. The NASA web site has a short video on the subject.

Q: Why doesn’t a duck quack echo?

A: This is an urban legend – duck quacks do echo. This site proves it.

Jul
25
2006

Marshmallows: Image courtesy Neil T.
Marshmallows: Image courtesy Neil T.
Q. What are marshmallows made of?

A. When I got this question I thought of “cow hooves” because that is what I was always told, and thought here’s an opportunity to resolve that marshmallows are not made of cow hooves. It turns out, that while it’s not just hooves, hooves are a part of one ingredient of marshmallows: gelatin. According to KraftFoods.com (makers of Jet Puffed Marshmallows), marshmallows contain: corn syrup, sugar, dextrose, food starch - modified (corn), water, gelatin, tetrasodium pyrophosphate artificial and natural flavor, and artificial color (blue 1). There are links to some of the less familiar stuff, but gelatin is the most interesting ingredient as far as I am concerned. Gelatin is produced through the prolonged boiling of animal skin, connective tissue, hooves or bones. But marshmallows are not the only place where you’ll find gelatin – jelly, gummy candies, Jell-o, ice cream, margarine, cream cheese, and many other foods also contain gelatin. So, if eating hooves weirds you out, you can relax, you’ve probably eaten several already and not even known it.

Q: What do cicadas eat?

A: Sap from plants. The cicada's mouth parts are covered by a long thin sheath called a labium. The labium contains four needle-like stylets which are used to pierce the plant and then act as straws that the cicada used to suck the sap from the plant. If you are into cicadas and want to learn more, Cicada Mania is the place for you!

Q: How come there are no Native American artifacts in the Science Museum of Minnesota?

A: There are lots, actually. Like most museums, we display only 1-3% of our permanent collections, which number 1.75 million objects. Our anthropology collections span the globe, but our one of our strengths is in Native American material culture from the Upper Midwest. Currently in the museum, you can see a small exhibit detailing the Prairie Island Dakota community with a bison robe, star quilt and contemporary artwork by Francis Yellow and another on Native American archaeology of the area on level 5 in the Mississippi River Gallery. In addition, the museum is working on an Ethnobotany project with Paul Red Elk (Lakota) in the Big Back Yard where we are germinating indigenously cultivated seeds in a three sisters garden, some which are over 900 years old. The Science Museum has been involved in archaeological field investigations since the 1950s. The majority of these collections have been from sites in Minnesota and include 100,000 documented specimens from over 200 recorded prehistoric archaeological sites. Currently, SMM’s archaeology research initiative focuses on Red Wing Archaeology.

Jun
12
2006

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.

Jun
02
2006

One of my responsibilities at the Science Museum is to collect the paper questions visitors submit to our featured Scientists on the Spot. Sometimes the questions don’t quite mesh with the featured scientist’s background, but are good questions anyway, or are entertaining, or fun, and I thought this would be a good forum to answer some of the questions that would otherwise go unanswered. So, here we go!

Q: How many people are there in the world?

A: According to the World Population Clock from the United States Census Bureau, as of 3:30pm on June 2, 2006 there are approximately 6,519,746,485 people in the world. This number is constantly increasing, so for the most current number, you should visit the link above.

Q: How many bones are there in the human body?

A: The adult human skeleton has 206 bones, but they don't all start out as single bones. Even long bones (like your femur) start out with the epiphyses separate from the main shaft, and these unify with time. There are 800 centers of ossification in the skeleton that unite with age, and as such, the number of bony elements in a subadult can vary greatly.

Q: What is a spider monkey?

A: From the Wikipedia entry on spider monkeys:

Spider monkeys are New World monkeys of the family Atelidae, subfamily Atelinae. Found in tropical forests from southern Mexico to Brazil, spider monkeys belong to the genus Ateles; the closely related woolly spider monkeys, are in the genus Brachyteles.

Here’s a picture of one kind of spider monkey.
Spider Monkey: Image courtesy dgphilli.

Q: How long does it take to digest gum?

A: My parents always told me not to swallow my gum because it would take seven years for it to be digested. That’s just not true. Chewing gum has five basic ingredients - sweeteners, corn syrup, softeners, flavors and gum base. The first four ingredients are soluble, meaning they dissolve in your mouth as you chew or in your stomach when you swallow. Gum base doesn't dissolve – it just passes through us with the rest of our waste a day or two after you swallow it.

Q: How old do you have to be to donate blood or anything else? Can you be under 18?

A: Well, if you are deceased and a minor the decision to donate you organs is made by your parents or legal guardians. Licensed drivers can make a personal commitment to organ and tissue donation by indicating their wish to donate on their driver's license application. This lets families and emergency personnel know your wishes. Donation information is available in all driver's license bureaus in Minnesota, North Dakota and South Dakota. In these states, if you indicate your wish to become a donor on your driver's license, it is legally binding. Parental authorization is required for individuals under the age of 18.

To give blood for the Red Cross, you must be at least 17 years old. For more information visit the American Red Cross blood donation site.

Q: What are nails made of?

A: I am going to assume the question is regarding finger or toe nails. Fingernails and toenails are made of a protein called keratin. Keratin is the major protein component of hair, wool, nails, horns, hoofs, and the quills of feathers.

Q: Do you like bubble gum?

A: Not really. My favorite gum when I was a kid was Big League Chew. Now I prefer Swedish Fish.

That’s all for now. Do you have any odds and ends questions you’d like us to try to answer? Leave them for us – we’ll try our best to answer them for you.