Science teaching tools that work

When learning physics, you pick up math skills. But there's a problem when students only learn how to choose equations and plug in the right numbers. The “plug and chug” questions you see on physics tests are of the easier variety. The hard questions are qualitative and conceptual. 

Here is an example of a basic conceptual physics question I saw from NPR.

Two balls are dropped from a building at the same time. Ball A and Ball B are the same size, but Ball A is twice as heavy as Ball B. Which ball hits the ground first?

a) Ball B hits the ground first.
b) Ball A hits the ground first.
c) They hit the ground at the same time.

If you understand Newton's second law (F=ma), you know that both balls hit the ground at the same time.

(Or if you like to guess, you know that c) is always the correct answer)

Even though one ball is heavier than the other, they have the same acceleration, 9.8 m/s/s, so they take the same amount of time to hit the ground.

Even students who have taken physics frequently get this question wrong. NPR reports that lectures are part of the reason students fail to learn the material. Students learn best when they are actively working, not when they passively listen to lectures.

Students do most of the talking in the “Peer Instruction” teaching model developed by Eric Mazur, a physics professor at Harvard. In this model students work together to solve problems in small groups. The professor poses conceptual questions to the students, who respond with answers via mobile devices. If a large percentage of the class answers incorrectly, the students work through the problem in their groups. After discussing with their peers, they answer the question again. The professor exists as a coach guiding the students during practice, rather than as a “sage on stage”.

According to Mazur, the approach works: "What we found over now close to 20 years of using this approach is that the learning gains at the end of the semester nearly triple."

As a physics major, I wish I had taken classes like this when I was in college. Learning through your peers is the best way to learn, especially in science. It also reminds me of an opinion article about science education I read in the LA Times. It referenced a study that sought to explain why some students were more prone to fail first-year calculus at UC Berkeley. The study found that students that never worked with other classmates were the ones that failed, even if they put in the study hours and the effort. The successful students were the ones that studied both by themselves AND in groups, where they helped each other out and figured out exactly where they stood in the class.

One caveat about Peer Instruction: it works best when students come to class prepared (i.e. they have already read through the material). Not all students are going to come to class prepared because many are used to relying on the lectures. As always, the students that go the extra mile and invest their own efforts into learning will get the most out of it.

Also, in this model students answer the same question twice. If only 29% of students answer a question correctly the first time, it sometimes improves to 62% of students who answer correctly the second time. But of course, if you think you answered incorrectly the first time, you can eliminate that answer choice the second time. Odds are that the scores will improve by simply repeating. And I wonder if the students get to see how the class answered overall.

Just some thoughts on group learning.

Dark energy highlights continued

Here is a great dark energy FAQ from Sean Carroll, a physicist at CalTech.

Einstein's greatest blunder (?)

In 1917 Einstein added a fudge factor, the cosmological constant, to the equations in his theory of general relativity. Before adding the constant, his equations showed the attractive force of gravity would cause the universe to implode in a Big Crunch. The constant kept Einstein's picture of the universe static – neither expanding nor contracting.

When Edwin Hubble discovered that the universe was expanding (the rate of expansion is what won this year's Nobel Prize), Einstein threw out the cosmological constant, declaring it his greatest blunder.

But the cosmological constant may still work. In fact, without the constant, the age of the universe is calculated to be much younger than the oldest observed stars. Since this makes no sense, the constant may hold validity.

How do spacetime and quantum field theory ultimately fit together? That has been the big looming question. One proposed “quantum correction” to classical mechanics is quantum mechanical vacuum energy. If there is such a vacuum energy, it may be associated with the cosmological constant.

But there is still an incredibly gaping margin of error: when physicists calculated the vacuum energy they came up with an answer 120 orders of magnitude (10^120 times) greater than what we actually observe. It would take me 2 minutes just to write out all those zeroes.

(hey you physics people, want to delve further?)

With all the advances in modern physics and the accomplishments highlighted by this year's Nobel Prize, there still remains an entire universe (or perhaps multiverses?) of mysteries.

Into the Future...

For the time being, budget cuts caused NASA to scrap its projects investigating dark energy using the James Webb Telescope. Fortunately, in 2019 the European Space Agency plans to step in with its Euclid mission.

The Large Synoptic Survey Telescope (LSST) in Chile will become another source of data for dark energy research.

Dark energy gets attention from Nobel Prize in Physics

*picture from NASA

Three American-born physicists won the Nobel Prize in Physics on Tuesday. Thirteen years ago they first made the startling announcement that the universe is expanding at an accelerating rate. They made the discovery by measuring the brightness of type 1a supernovae, explosions of small stars known as white dwarfs that can outshine an entire galaxy and can radiate as much energy as our sun will in its entire lifetime. The measurements showed that the supernovae were dimmer than what was expected, suggesting that galaxies were moving apart at an increasing rate.

At the time scientists were skeptical of the results – the prevailing view was that the universe was slowing down in its expansion. Yet two teams in competition with each other (one led by Saul Perlmutter of the Lawrence Berkeley National Laboratory, and the other headed by Brian Schmidt of the Australian National University in Canberra and Adam Reiss of the Space Telescope Science Institute and Johns Hopkins University) used independent lines of evidence to reach the same results.

The Nobel Prize brings attention to the study of a mysterious component of the universe called dark energy.


What is dark energy?

The simple answer: we don't really know, but physicists believe that dark energy is the “thing” that causes the universe to accelerate in its expansion. It's a little unbelievable that dark energy makes up about 73% of the universe, and yet we know so little about it. There are three properties to note. First, look at the name: dark. It is 'dark' because we don't see it; we do not observe dark energy interacting with matter at all. Second, it is smoothly distributed. The density of dark energy is uniform throughout space. And third, it is persistent. Unlike particles of matter, dark energy doesn't cluster together or dilute away.

The difference between dark energy and dark matter

Dark energy is not the same thing as dark matter. Again, look at the name. Dark energy is energy – it doesn't consist of particles. Dark matter consists of particles of matter. Physicists think it's there but they have yet to directly detect the particles.  However, they have observed gravitational influences (in settings like galaxies, clusters, large-scale structure, and microwave background radiation) that they attribute to clusters of dark matter.

Dark matter makes up about 23% of the universe. Actual matter – the stuff that the Earth is made up of, and the stuff that you and me interact with on a day-to-day basis – makes up less than 5% of the universe. Crazy.

More to come soon...

Depressing study shows people are depressed

Do studies predict the worst? In Nature’s Trend Watch last week the prevalence of obesity in the US and the UK is projected to grow from 32% in 2007-08 to 50% in 2030 for men, and from 35% to 45% for women. One obese person out of three people seems high enough as it is. But one out of two people is just…depressing.

Another study in Nature reports that mental disorders affect over one third of all Europeans. Can they do a follow-up study of how many of those Europeans got anxious or depressed from reading all the other depressing studies out there?

I generally read study results as interesting opinions that could potentially become facts…or not. Just something to think about. But it is irritating when magazines take those studies and tell you to make changes with your life. “Study says chocolate goes straight to your hips. Try eating vegan tofu desserts instead!” And then “Study says chocolate has antioxidants. Go to See’s Candies today!”

I’ll go be happy now and distract myself on Youtube.

Building a toolbox for science and math literacy

I'm very excited: an opinion article I wrote about why we need more exposure early on for science and math education is published in the San Diego Union-Tribune today! The basics:

1) Science and math can be awesome!

2) Learning math is like investing in a good toolbox to build a house.

3) Having a mentor/having a challenge is invaluable.

You can read more about good toolboxes that help our less-than-stellar education system in science and math here:

http://www.signonsandiego.com/news/2011/aug/20/building-a-toolbox-for-science-and-math-literacy/

Palm trees threatened by invasive pest

What do you think of when you picture southern California? The breezy beach, a cloudless, sunny sky…and maybe some palm trees? Okay, how about a lot of palm trees. They are everywhere. 

Let’s hope our palm trees stick around. 

(photo credit: John Kabashima, UC Cooperative Extension)

The red palm weevil, a small beetle-like pest that can quickly kill palm trees, was first discovered in California last year. Weevil larvae burrow deep into the trunks of palms and grind its insides into mush. Adult weevils munch on palms, including the top-most leaves.

You can read more about it in an article I wrote for this month’s issue of CAPCA’s Adviser magazine, “What’s Bugging California’s Palm Trees?” I had the opportunity to interview Mark Hoddle, an entomologist at UC Riverside who researches the red palm weevil and conducts field work to contain the pest. He keeps a well-documented, up-to-date blog here. 

Speculated to have come from Southeast Asia, its invasion now threatens palms in urban areas, native palms in the desert, and California’s date crops and palm nurseries. In May this year, a second weevil species was caught in a trap in San Diego County. Traps are currently set up around the first sighting in Laguna Beach and along the Mexico-CA border (where the second species was found). 

Ever since doing this article I have put on my palm tree glasses. As a southern California native, I am so used to palm trees that they blend into the background. They weren’t so different from any other tree. But knowing that they are iconic to our state, especially for those who come to visit, I can see ‘em now! 

Pale Blue Dot Animations

There is a whole world to explore within a pinhead. Consider that an atom is roughly seven orders of magnitude smaller than a pinhead, something you can still see with the naked eye. If you blew up that pinhead to the size of the earth, you could at last hold an atom in your hand like you would, say, a water balloon.

And then there is Carl Sagan shrinking the massive size of the earth to a pale blue dot.

This "joyful, sad, sweet, and wonderful" animation posted on PBS Nova's blog got me thinking. It captures an excerpt from Carl Sagan's book A Pale Blue Dot.


Pale Blue Dot - Animation from Ehdubya on Vimeo.

Science is a tool that can help us better appreciate the beauty of nature. It doesn't reduce the mystery and art of life by explaining/revealing its underlying mechanisms; rather the opposite, it gives us more perspective.

Taking a walk outside helps me see I'm a tiny creature amidst people, cars, buildings, trees, mountains... I'm still trying to imagine zooming out on me, my city, California, the US, and then the earth until there is nothing but a pale blue dot...

"Surely you're joking, Mr. Feynman!"

Richard Feynman was that rare combination of genius and accessibility to the non-physicist. If there was one thing he was confident in it was sitting down with a seemingly impossible puzzle until he solved it. He also played the bongos, told funny stories, and pulled a great poker face on the (in)appropriate occasion.

If you read any of his stories from the book "Surely You're Joking, Mr. Feynman!", I recommend Safecracker Meets Safecracker. It's a great example of how Feynman rolls, and I cracked a grin (bad pun?) while reading it.

Feynman developed an active observance of social irresponsibility from the great mathematician John Von Neumann, who gave him this advice:

You don't have to be responsible for the world you're in.

Perhaps due to this lack of seriousness, Feynman romps through some entertaining twists and turns in life.

Read The Dignified Professor to find out how the whole business that got him the Nobel Prize "came from piddling with a wobbling plate". Burned out from working on the atomic bomb project during WWII, he felt an unusual twinge of disgust for physics in his new life as a young college professor. He asked himself why he had once enjoyed doing physics and realized it was because he used to do whatever he felt like doing - i.e. play with it.

An example of Feynman's idea of play: figuring out how to determine the curve for water running out of a faucet.

So when he was at the cafeteria he saw a guy throw a plate in the air and noticed the plate wobbled. For fun he set out to determine the motion of the plate wobbles. "It was effortless. It was easy to play with these things. It was like uncorking a bottle: Everything flowed out effortlessly. I almost tried to resist it!"

Maybe a little more effortless for him than for the average person, but he set out to actively play just like anyone might. In science I see this sense of play slip through fingers like sand (I include my own undergraduate experiences here). It gets replaced with talk of "the future of science and the betterment of society", or maybe just getting a good grade.

At any rate Feynman's stories are a good read and he packs a joy for physics into them. 

Why promote science fairs

This week the LA Convention Center was filled with poster boards and precocious students for the Intel International Science and Engineering Fair. The biggest science fair in the world attracts more than 1,500 participants from 65 countries. This year’s $75,000 grand prize went to Matthew Fedderson and Blake Marggraff of Lafayette, California for their research on treating simulated cancer cells with Compton-scattered secondary radiation. Nothing less than professional-level science projects (albeit with the help of a scientist mentor in most cases) can be expected from ISEF.

I participated in the fair for a day as a volunteer interpreter and was able to meet some of the Japanese students. They qualified by winning national-level high school science fairs in Japan – impressive students on paper and in person.

In science fairs the first hurdle is to come up with a good question. You can’t just ask a big question like, “How can I cure cancer?” The best questions come from a simple observation in your surroundings. The next hurdle is to design a clean, simple experiment to test your hypothesis.

I helped out with a student who experimented with liquid nitrogen. While playing with liquid nitrogen he noticed that some materials boil within the nitrogen, calm down, and then re-boil. He asked, “Why does re-boiling occur?” He observed a simple mechanism and being curious, wondered how it works. After testing re-boiling for many materials he found that re-boiling occurred the most for materials with high thermal conductivity.

With the help of a high-speed camera he also discovered that a film of bubbles collects on the material before it re-boils. He then tested whether the film of bubbles causes re-boiling by breaking the film with a heating wire. That’s the part of the experiment that I really like – he found a way to disrupt the film of bubbles and observe what happens in its absence. It’s a well-designed experiment. He found that when he applied more current to the heating wire, the material finished reboiling faster. The conclusion: cooling can be accelerated if the film of bubbles is broken by non-uniform heating.

The schedule for the students is pretty grueling. They are at the convention center from 7am to 6pm, where they present their experiment to judges in English, a second language for them. One of the people from the Japanese team remarked that these students can present their science projects better in English than they can do small talk in English. Ask them how surface area affects reboiling in liquid nitrogen and they’ll answer straight away. But as a judge if you try to break the ice with, “Have you visited Disneyland yet?” they get a little thrown off.

I was very happy to meet these students. They were mature and at the top of their game. One of them gave me a Japanese fan, too! There was a clip from NPR that pointed out that kids (especially those at this science fair) can contribute to science and offer something different. Where an older, trained scientist may think that something will never work, a kid might look at something in a new way. She might ask, “Why not?”

UCR Science Lecture Series

Yesterday I went to a talk held at UCR as part of a science lecture series open to the public. Cheryl Hayashi, a biology professor at UCR, gave a talk on biomimetic technologies – innovations that imitate nature. Hayashi advocates that there is a lot to learn from nature. Shaped by natural selection over a super-human stretch of time, designs found in nature are often superior to manmade technologies.

Hayashi’s slight frame packs a bundle of energy and enthusiasm for her work. She wears comfortable shoes and slacks and sports hair slightly more fashionable than the average professor. “Do you see this here?” she asks as she walks from one side of the room to the other, making sure that everyone in the audience can see what she is pointing out. It is a picture of sand. “There are two eyes here,” she draws her hand over the picture, “and here are the legs coming out.” The audience “oooohs” in comprehension – now we see a spider camouflaging itself in the sand. Hayashi shoots a mischievous look at us and exclaims, “You guys will believe anything, huh!” She’s just kidding, though. She assures us there really is a spider there.

Hayashi's fascination with nature is infectious as she takes us through current technologies that imitate nature. She offers the example of a butterfly that does not use pigment to color its brilliant metallic blue wings. Instead the wings are made of tiny lens-like scales that nature has optically engineered to reflect blue wavelengths of light back to us. Sonar, often used by the military, has been used for much longer by bats and dolphins to detect their surroundings. Speedo recently developed swimsuits that mimic shark skin to create more efficiency for swimmers. And the inspiration for Velcro came to an inventor when he came back from a hike to find himself and his dog covered in fast-sticking seed burrs.

Hayashi herself works with spiders and researches spider silk. She urges us to imagine what it would be like to be a small spider interacting in a giant’s world. They need their silk to interact with their surroundings. Incredibly, spiders create 7 different kinds of silk. Hayashi’s lab measures the properties of the silk and researches how spiders produce it. Spider silk can stretch to twice its length without breaking and has superior strength, extensibility, and toughness compared to manmade materials. While a string of spider silk 1mm in diameter could lift a cat (11 pounds), a 20mm diameter string could lift a hippo (4400 pounds). That’s a tough string of silk.

Some promising applications for spider silk include tough, lightweight gear such as bullet-proof vests and medical products such as bandages and sutures. Spider silk also exhibits muscle-like properties: wetness and humidity cause the silk to contract. It could provide an alternative to artificial muscle tissue, which contracts through electrical impulses. Producing spider silk in mass quantities for commercial applications presents another challenge and opens a new topic of research.

After this talk I am left impressed by designs that occur in nature. I am also curious – what does Hayashi do with spiders she finds in her house? She wouldn’t squash them, would she? Perhaps she takes them with her to lab.

For more info on the Science Lecture Series, visit here!

Pirate puzzle added

In our continuing adventures with the unnamed pirate, he encounters tigers and treehouses in puzzle number 3. See if you can help the pirate solve the puzzle with your logic and wit here: Pirate Adventures with Math.

The Big One

In Japan they call it "Tokai", and here in California we call it the "Big One". It's that massive earthquake that you're waiting for if you live in an earthquake prone region, and in California it would occur on the San Andreas fault.


The LA Times has an interesting article about seismologists that are creating underground images near the San Andreas fault. It looks like pretty intense field work. The scientists set off explosions along the fault and record the speed of seismic waves as they travel through the Earth's crust. The recordings are used to generate underground images. "So far, they had put out more than 4000 seismomemters, and the night crew had set off more than 100 explosions."

The more we know about the structure of the San Andreas fault, the more we can determine the impact of shaking from an earthquake like the Big One. Previous studies project 2000 deaths, 50,000 injuries, and $200 billion in damage from a 7.8 quake near the fault. That's much less than the recent quake and tsunami in Japan, but still significant.

I like this Google map of the San Andreas fault. It’s easy to zoom in and pan around on the fault. It’s right up against the base of the mountain ranges in some areas.

Also a detailed site about the San Andreas here.

While this fault is above ground, I wonder how they are studying rifts that are under the ocean...

Quake devastation...and tracking what went wrong with Japan's nuclear reactors

At my house the TV is tuned to the Japanese channel for NHK’s coverage of the damage and devastation from Friday’s earthquake. It’s relentless coverage of the dead and missing, shots of people who have evacuated to shelters, bell chimes sounding new earthquake warnings, and the latest from the Fukushima power plant. 

Everyone is comparing the situation at Fukushima to past events: it’s worse than Three Mile Island but not as bad as Chernobyl. But will it become worse than Chernobyl? That’s unclear, but here are some sources to understand what is going on:

NPR has a visual guide to what went wrong inside the nuclear reactor. So far there have been explosions at 4 reactors. NPR is also tracking the latest news on the reactor.

A more detailed explanation of the fundamentals here.

Although people are concerned about the health effects of radiation exposure, this article from the Washington Post brings up the psychological damage that may have just as much significance.

And my summary from what I've gathered so far:

After the earthquake and tsunami the plant lost the necessary power to cool the fuel rods. The fuel rods contain fuel that generates heat through nuclear fission. The temperature of the fuel rods must remain stable to prevent a “nuclear meltdown” that could result in radiation leaks. With the cooling system failing, too much water boiled into steam and increased the pressure within the reactor. The power plant workers vented steam outside of the reactor to reduce the pressure, but they also added cooling water and caused hydrogen to build up inside the reactor. The steam and hydrogen gas were vented into the air and a hydrogen explosion occurred.

Also, I am following the updates on the situation at Fukushima because it's interesting and because there are health risks, but there is so much going on in Japan beyond what I can fathom. Ganbare Nippon!

Ars Technica science video contest winners

Last week Ars Technica chose the winners for their science video contest in December:
http://arstechnica.com/science/news/2011/02/ars-announces-the-science-video-contest-winners.ars

These videos were fun to watch, and they ALL succeed in teaching you something about science while entertaining you.

Two videos explain the concept of a fourth dimension. One of them has an excellent soundtrack and the other one has a really good narration.

There was also a video about the Doppler effect!! That's one of the physics concepts that is the most fun to explain to others...and in that video it looks really good when you animate the Doppler effect.

To explain how antibiotics work, one video animates M&Ms and Twizzlers to great effect.

Last but not least the Large Hadron Collider is explained without any talking. That one was exciting to watch. When they show the "99.9991%"-ish number, are they talking about the speed at which the protons are accelerated?

Man, it would be so fun to pull off a video on this level...

Just for fun

My friend and I just submitted a video to the Ars Technica science video contest! Anyone can submit a video with a science topic related to biology, physics, or math.

This friend from work is into photography and we have fooled around with the video on her camera for some "internal marketing videos" at the office. So...we decided, why not, let's make a science video.

Here it is: How Making Music Works

It's nothing fancy so don't expect anything. But I like the drums, piano, and glasses of water that we demo.


And now I really respect anyone that makes videos! It's hard to plan out every shot and takes teamwork. But it's also fun and this contest makes me want to try some more!

More pirate puzzles

Finally I posted the next puzzle in the pirate's adventures on an exotic island. What will the pirate do when he meets the island natives? Find out and see if you can help the pirate avoid certain death with some logic skills!
Pirate Adventures with Math (Look for puzzle no.2)

Some simple math/logic puzzles

I've been doing a couple math puzzles here and there and thought I'd add a story to these puzzles because...why not? Everything is more fun with a story!

These are some simple logic puzzles encountered by a pirate when he visits a strange and exotic island...

So far I've posted puzzle number 1! You can read it on the 'Pirate Adventures with Math' page that links to this blog.

Is coffee good for your health?

“I’m going to cut down on the coffee,” resolves a coffee drinker who may have an addiction problem. Caffeine sometimes lends coffee a negative spin. The withdrawal effects of a caffeine addiction can be pretty bad: headaches, anxiety, mood swings, and nausea. On the other hand, too much coffee at once can make you jittery and on-edge and increase your heart rate. People talk about the “post-caffeine crash". For the first couple hours you’re speeding through your work, and then the energy is gone and you want to keel over. From personal experience, drinking coffee before you sail out on a small boat will make you spew it back out again (apparently it’s from the acids in the coffee).

But many recent studies report the health benefits of coffee. According to these studies coffee may reduce the risk of type 2 diabetes, liver cirrhosis and liver cancer, Parkinson’s, and coronary heart disease to some extent or another. Other studies show that coffee can boost athletic performance and may possibly increase your lifespan. There always seems to be a new study popping up to report some health factoid like:

• Coffee drinkers with a modest intake, two to four cups per day, had a 20 percent lower risk of heart disease compared to those drinking less than two cups or more than four cups.

Okay?! So tomorrow I can wake up, drink three cups of joe, and tell myself, “This daily ritual is making me less susceptible to heart disease!”

Or can I?


A scientific study can only do so much to influence your health habits. There are reports out there saying that it takes more than 6 cups of coffee daily to get any significant health benefits. That’s good news for a heavy coffee guzzler, but 6 cups for me? No thank you. I’d be bug-eyed, anxiety-ridden, and sitting on the toilet for the better part of the day.

Sometimes those health articles have links to the original study, so I clicked on a couple links and found:

Study #1: from the Journal of the American Heart Association about “Tea and Coffee Consumption and Cardiovascular Morbidity and Mortality”

Study #2: from Hepatology about coffee consumption and the risk of liver cancer.

The strengths and limitations of a study have to be considered for it to be scientifically valid. Both studies I looked at follow a large number of participants (about 37,000 participants in one of them) for a long time (13-19 years). The studies tracked how many people got coronary heart disease (CHD) and liver cancer, respectively. The actual number of people diagnosed with CHD (1950 people) and with liver cancer (128 people) was relatively low. The number of participants and the long follow-up are good, but is 128 people big enough for a good statistic? Working with a small number of diagnosed participants could be a limitation.

Other limitations include self-reported data - people may lie about their health habits. Also, the studies attempt to adjust for other health factors like the history for a particular disease (e.g. diabetes), age, educational level, smoking and alcohol habits, weight, etc. These adjustments are made to establish that coffee consumption is the cause, not a correlation.

Interestingly, in the first study, tea and coffee drinkers were found to have opposite health habits. Tea drinkers tended to have healthier habits, whereas coffee drinkers tended to smoke and drink more, weigh more, and even had a lower educational level.

It’s also interesting to compare the health trends for the population samples of different regions. The liver cancer study focused on a Finnish population with high coffee consumption and a low risk of liver cancer. The Finnish population sample is advantageous because the variables in question are much better isolated. Previous studies with Italian and Japanese populations were obscured by higher rates of liver cancer that could be attributed to multiple factors.

These studies also lend some insight into the chemicals at work in tea and coffee. Caffeine and diterpene alcohols in coffee “could increase cardiovascular risk by increasing serum cholesterol and decreasing insulin sensitivity.” But coffee also contains chlorogenic acid with antioxidant properties that could reduce the risk of coronary heart disease. “More research necessary”, of course.

These studies offer fun facts and health bytes, but how much influence do they actually have?

When you get down to it, health advice is simple and straightforward. “Everything in moderation” is a good dose of common sense. Most articles on coffee conclude that coffee has been around for a while, and you don’t need to feel guilty about drinking it in moderation. Too much may get you wired. Too little? Well, you probably don’t need to care. Considering your own personal health background and making your own lifestyle choices speaks to common sense more than following a couple numbers and statistics.

Horse racing made easy, brought to you by your local physicist...

What is it about physicists? The other day I came across an xkcd comic that sums it all up.

Have you heard that one horse racing joke? It pretty much goes the same way. There's a breeder with a stable of race horses and he's looking for a plan to make them winners. So he asks a biologist, a chemist, and a physicist if they can come up with a solution.

The biologist says, "Yes, I can develop a breeding technique to give you the fastest and most powerful horses! In a couple of horse generations you'll have a stable full of winners."

The chemist cuts in and says, "My solution is much faster than that. I can concoct a drug for you to give to your horses. It will increase the speed of your horses by 10%, with the side effect that the lifespan of your horses will decrease by 10%."

The physicist looks up from her notebook and says, "I've got the solution! Okay, guys, let's first assume that each horse is a perfectly round sphere..."

I love those scientist/engineer/mathematician stereotype jokes. If you have a good one, send it along! :)

Ocean Waves

Waves are everywhere! They come in many different mediums and on different scales: electromagnetic waves (radio waves, visible light, Xrays), sound waves, vibrations on a guitar string and – ocean waves!

I’ve been thinking about ocean waves after I started taking a surfing class. So far, thinking about the physics of surfing has been much more pleasant than thinking about its dangers, like stepping on a sting-ray, getting hit by a surfboard, or getting pulled out to see by a rip current and drowning. These things scare me. I like to think that being scared of everything is just the tradeoff for having a vivid imagination, but anyways, I digress.

How do ocean waves work? To start a wave you need an initial energy source, and for the ocean that is the wind. A wind that blows in the same direction over a long distance at high speed can generate massive waves. The wind pulls against the surface of the water and transfers energy that builds up into waves.

They travel across the ocean and break where the ocean floor rises towards the shore. The rising ocean floor will slow down the water moving beneath the wave due to friction. The top of the wave will not slow down as much because it doesn’t come into direct contact with the ocean floor. The result is that the top of the wave travels faster than the water moving beneath it, causing the wave to rise up and curl forward. Eventually the wave becomes unstable and breaks on the shore.

*one step above a napkin doodle

This is the area where the wave smashes into you in sprays of salty sea water unless you jump the wave or ride over it on your surfboard. If you are like me this is also the area where you get stuck when you see a big wave rolling towards you and think, "I don't need to go out any further."

Actually catching a wave is much more fun than trying to get over them unscathed. They tell me that in order to do that, you have to paddle a lot! You can catch a wave when you are paddling at the same speed as the wave (you need momentum to ride a wave).

That’s a very basic overview (no Laplacians here). There is more physics involved including tides, but for now, it’s about time I posted something already!