Stories tagged digestion

Tyrannosaurus rex: Ready to gulp you down.
Tyrannosaurus rex: Ready to gulp you down.Courtesy Mark Ryan
Talk about fun. Take this cool quiz to see how long you'd have to be in a T-rex's digestive tract before you'd be totally digested. Evidently, it would take a guy my size about 17 hours. This is important information to have that could someday save your life. You never know when knowledge like this might come in handy. Take the quiz yourself.


From time to time as I gather up the questions from the on-site Scientist on the Spot features we find some good questions that don’t connect well to the featured researcher. Here are some of those questions.

Why are stars circles?

Iapetus' equatorial ridge
Iapetus' equatorial ridgeCourtesy NASA
I am assuming you mean, why are they round or spheres? It’s because of gravity. The larger something is (or the more mass something has) the more gravity it has. That gravity pulls equally in, so that’s why stars and planets are round, gravity makes them that way. The fancy-pants scientific name for this is isostatic adjustment.

But the Earth, for example, is not a perfect sphere – it bulges out in the middle because of its rotation. Smaller asteroids are oddly shaped because they don’t have enough mass to produce the gravity necessary to pull them into spheres. Some planets are oddly shaped too, and scientists are not sure exactly why. Saturn’s moon Iapetus is a great example. It is for some reason shaped more like a walnut and has an equatorial ridge that scientists cannot come to a conclusion as to how it formed.

What is a pimple?

Well, our skin has pores which are connected to glands that produce sebum – like an oil. Sebum is a good thing - it acts to protect and waterproof our skin, and keeps it from becoming dry. When these pores get blocked by dirt or dead skin (which we shed constantly) the secretions of sebum that would normally come from the pore are blocked and build up. These can become infected with bacteria which causes pimples to form.

The harder question is for me – to pop or not to pop. I can’t resist popping a pimple – it is a character flaw that has resulted in me sporting many a wound worse than the original zit. A great “how to pop a pimple” step-by-step is posted here.

Why do beans make us fart?

When food gets to your large intestine it is eaten by the 200+ different species of bacteria that live there and target parts of the food our stomach and small intestines can't digest, and gasses such as methane, hydrogen and hydrogen sulfide are produced as a by-product. Beans contain several sugars that we can’t digest, so lots of gas is produced by bacteria eating the otherwise indigestible material.

What is the scientific name for a pig?

Sus scrofa domestica.

What is the moon?

The big whack
The big whackCourtesy NASA
You mean besides being the only natural satellite of the Earth and the cause of the tides and so forth?

I think that the Earth collision theory (also known as the Big Whack) for the creation of the moon is the coolest, and is the one that is the most accepted today. The hypothesis goes that a Mars-sized (Mars is less than half the size of the Earth) planet collided with Earth a looooooooooong time ago and the debris that was created orbited around the damaged Earth and formed into the moon through a process called accretion – or the growth of large bodies like the moon by gravitationally attracting more matter. So the little bits of debris were attracted to bigger and bigger bits as the bigger bits had more gravity. As we learned above, the spherical shape arises from gravity as well. It is believed that as a result of the collision the smaller planet (Theia) was destroyed, ejecting its mantle into space while its core sank into Earth’s core.

Did you know that the moon is in synchronous rotation with the Earth? That means it keeps nearly the same face turned towards the Earth at all times.


Added duties: A team of researchers at Duke University think they've found the purpose of our appendix: to produce needed germs for our digestive track to help break down our food.
Added duties: A team of researchers at Duke University think they've found the purpose of our appendix: to produce needed germs for our digestive track to help break down our food.
All during college, I had this irrational fear each time finals week would roll around that I would be struck with appendicitis. It never happened and to this day, I still have that little bugger jiggling around down there by my intestines.

And if this group of researchers is correct, I should be glad I still have it. A team of scientists at the Duke University Medical School thinks its found the purpose of the appendix.

That little dangler found between the end of our small intestines and start of our large intestines could be producing good germs for your digestive system. Our body actually uses bacteria to help digest our food. And if we lose too much of it, the researchers surmise, the appendix produces and kicks in a new batch of bacteria to help us keep breaking down our food.

Chew on this stat for a second: there are more bacteria than human cells in our bodies. Most of that bacteria is good and works in out digestive system to process our food.

This new news flies in the face of the long-held idea that the appendix had no current purpose. Some scientists figured that it was a leftover from some bodily function that humans had evolved out of over the years. Doctors routinely snip it out when doing other surgeries in the area to prevent the patient from the chane of suffering appendicitis. The most recent figures, from 2005, from the Centers for Disease Control and Prevention report that 321,000 people in U.S. where hospitalized for the condition.

The new theory figures that the appendix can regenerate bacteria after too much of it is lost by the body. Severe intestinal problems like cholera or amoebic dysentery can completely flush a person’s body of all of its digestive germs.

In our more diverse culture of today, we actually don’t need out appendix as much because we’re exposed to many “good” germs on a regular basis, the scientists postulate, with us picking them back up, if we need them, from other people around us. That has made our appendix less needed.

Helping back that idea up are statistics that in less developed countries, where an appendix is still very useful, the incidences of appendicitis are much lower.

Other medical researchers not connected with the study say the idea seems credible.

And we should all still be worried our appendix if it starts to hurt. If they become inflamed, it can be deadly with about 300 to 400 Americans dying year because of the condition.


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.