Monday, December 29, 2008

Songs in the Key of Science

In college I came across a recording of song entitled "Why Does the Sun Shine?" performed by the quirky alternative rock stalwarts They Might Be Giants.

As far a science songs go, it rocks! Here's a YouTube clip that puts visuals to the song:

It's a Cover?
I dug around the internet and discovered that "Why Does the Sun Shine?" was originally written in the 1960s. This
website has a brief history and links to all the songs of the science albums.

Cheesy Songs
Songs about science may not get radio play, but they have their place in education.

My high school chemistry teacher had an album of science songs that he would play at the end of class while we were packing up our things. These songs were bad and, as is the rule for all bad songs, they would stick in your head.

Come exam time, all complaints would disappear because most people would hum these songs to get to the right answer.

Do you have memories of any science songs? Please share.

Dr. Dave

Friday, December 19, 2008

Does an Astronaut's Nose Run in Space?

On Earth, gravity attracts everything towards the ground. This makes it very easy to figure out which way is up and which way is down.

Gravity is also the reason why mucus (the “runny” part of a runny nose) always comes out of your nose.

Mucus 101
Mucus is made up of water, sugars, and proteins. Unlike tap water, mucus is thicker and doesn’t flow as easily. Liquids that don’t flow easily are said to be viscous. White glue, pancake syrup, and motor oil are examples of viscous liquids.

All liquids flow. Liquids poured on a counter top will spread out until it reaches the lowest point or it can’t flow anywhere else. Liquids flow because gravity is constantly attracting all the molecules to the ground.

In space, the rules change. Check out this interesting video that shows an astronaut demonstrating how water behaves in space.

That’s not how water behaves on Earth, but it's really cool!

What’s going on?
Without gravity, the water molecules are no longer being pulled towards the ground. Instead, it seems to just float like the astronauts do.

So, if an astronaut had a runny nose in space, where does the mucus go in the absence of gravity?

Since there is no gravity to pull the mucus out of an astronaut’s nose, I think that a runny nose in space wouldn’t run. In other words, the mucus would probably stay in the astronaut’s nose until it is blown out.

A runny nose is annoying here on Earth, but can you imagine a nose full of mucus that doesn’t run? That would feel very weird!

Dr. Dave

Wednesday, July 2, 2008

It's Not Easy Being Green - The Electric Car

When Kermit the Frog first sang the line “it’s not easy being green,” I don’t think he was talking about the environment. We live in the green age in which there is an overwhelming drive to reduce our impact on the environment.
Recycling is a way for everyone to do their part for the green movement. California has been green for a long time. I remember separating paper, plastic, aluminum and glass from garbage for recycling at least 15 years ago, if not more.

Al Gore is doing his part by talking about the relationship of greenhouse gases to climate change. Although some people doubt this connection, most people would agree that the weather is not what it used to be. That’s climate change in my book.

What about fuel efficiency?
With gas prices well over $4 at every pump I visit, I have been thinking about hybrid cars. I know many people who own a Toyota Prius, which can get about 45 miles per gallon While this gas mileage sounds terrific, I was thinking about alternatives to gasoline powered engines.

The federal government is making a big fuss over hydrogen fuel cells and throwing a lot of money into developing this technology for widespread use. While the idea sounds good, I'm really concerned about the storage of hydrogen and oxygen, the fuels that makes the car go. I don't know enough about this technology, and I’m sure there are some very smart people working on this problem.

What about an electric car?
Believe it or not, this has already been done.

When I was in college, I was introduced us to a car called the EV-1, which was made by General Motors.

An electric car? Surely it would be wimpy! I was wrong. The EV-1 was fast, it could go from 0 to 60 mph in 8 seconds, and its surprisingly quiet. The EV-1 had a range of 120 miles on a single charge.

I figured this car would be all the rage in California, since the state was into being green before it became popular. Interestingly enough, 1997 was the last I heard of the EV-1, and then I saw a documentary called “Who Killed the Electric Car?” in June 2008. This documentary discussed the EV-1 and points out what an amazing machine it was. The car was ahead of its time.

Eventually the program ended. Why? Was it corporate greed? Was it there not enough demand? Watch the documentary and come to your own conclusion.

I imagine that high gas prices means that there would be significant demand for an electric car. I hope General Motors and other car makers follow up on it. Technology has improved over the past 10 years, so I imagine the next electric car will be even better. My fingers are crossed.

Dr. Dave

Wednesday, May 21, 2008

The Physics of Freerunning

Good news everyone, I am officially Dr. Dave! I spent the past few months writing my Ph.D. thesis and I successfully defended my dissertation. I apologize for not posting regularly, but I am sure you understand.

Thesis Break, Bond Style!
While I was writing my thesis, I would occasionally take a break and watch a movie. One of the movies I watched was Casino Royale, the most recent entry
in the James Bond franchise.

Chase scenes are standard in Bond movies and Casino Royale had its fair share. My favorite is when Bond pursues a bomb maker, Mollaka, on foot through a construction site in Madagascar.
Below is a link to the scene posted on YouTube. The clip is about 9 minutes long.

In this foot chase, Bond and Mollaka have two different styles. Mollaka is graceful and efficient; Bond is aggressive and haphazard. It is clear that Mollaka has an advantage over Mr. Bond. What's Mollaka's secret?

Free Running

S├ębastien Foucan, the founder of a sport called free runnin
g, played Mollaka. Free running is a sport that is dedicated to efficient motion between two points.

During the foot chase, Mollaka knew how to use his environment to keep him moving forward. While his jumps were very fancy to watch, he was clearly using the laws of physics to his advantage.

Rolling, Rolling, Rolling
I have seen similar acrobatic free running feats perform
ed during martial arts demonstrations. The core philosophy of many martial arts is to redirect energy and I imagine the same holds true for free running.A basic move taught in many martial arts is the roll. A proper roll is a useful move that is designed to dissipate energy in a fall or jump. Look at this YouTube video showing how rolls are done. The people in this video clearly know what they are doing. Please don’t try this at home without the proper equipment. You can easily injure yourself.

The examples toward the end of the video show why the roll is a great move–it helps the free runner maintain his forward momentum after a jump and places him on his feet.

The Physics of Going Splat
In the YouTube examples above, we can see how rolling is very useful to free runners. Let’s learn about the physics of this motion.

Let’s imagine we have a ball of pizza dough. What happens if you throw it against the wall? I would predict that it would go splat and flatten. Why? When the dough collides with the wall all the energy of motion–called kinetic energy– is instantly absorbed by the pizza dough.

Let's think about what happen in another example.
Now imagine that we roll the ball of dough on the ground towards a wall. What happens in this case? The ball of dough will gradually lose speed before hitting the wall. In this example, th
e dough is more likely to maintain its shape because the energy is lost gradually as it rolls rather than suddenly at impact.

In both cases, a similar amount of energy is lost. What matters most is the amount of time required for the dough to slow down. If it the dough stops suddenly, then it will flatten. If the dough slows gradually, it will retain its original shape.

Over the Handlebars
While pizza dough is a good example, let’s think about how this works on a human body. The following is a true story:

A friend of mine was riding his bike in the park. Suddenly, a child jumped in front of him, causing my friend to swerve and avoid the child. Unfortunately my friend hit a bench and went flying over the handlebars. Being a black belt martial artist, he instinctively curled up into a ball and rolled on the pavement; he rolled a few times before coming to a complete stop.

The Physics of Not Going Splat
My friend was able to avoid significant injury because was able to roll and gradually dissipate his kinetic energy. Can you imagine what would have happened if he landed hard onto the pavement?

His body would have suddenly impacted the ground and instantly absorbed all kinetic energy. If you have ever experienced a crash, then you know this is a painful experience.

In the example of pizza dough mentioned above, a direct impact caused the dough to lose its shape. On the human body, a sudden impact would cause significant injury, like cuts and bruises, even broken bones. Ouch!

Whether you are a martial artist or a free runner, the ability to move with proper technique helps to prevent injury. By understanding physics we now know why. Remember, it all boils down to how fast or slow kinetic energy is dissipated.

Dr. Dave