Happy Pi Day, Albert

Last Updated (Wednesday, 10 March 2010 15:24) Written by Raymond Nakamura

This year, different school boards have March Break at different times. But if you're looking for something to do on March 14, why not celebrate Pi Day, in honour of that splendid number (3.14...), the ancient ratio between the circumference and diameter of a circle with digits that keep going and going. It is also Albert Einstein's birthday, but he already gets enough publicity. At Science World, March Break (March 11-15) festivities will be a Pi-rate theme. Coincidence? Maybe.

Anyway, here are some things to do on pi day—

3. 

My favourite is strawberry rhubarb. Or maybe pumpkin. Or lemon meringue.

1 

Make a pi necklace.

You assign a bead type to each digit and string them according to the digits in pi.

4 

Read about pi. Life of Pi is interesting, although I'll warn you that it doesn't have many numbers in it. 

1 

Find your birthday in pi

You put your birth date in and the program finds a matching sequence of numbers.

5 

Find out where your name falls in pi.

The letters in your name is converted to a string of numbers which is sought in pi. Longer names are less likely to be found.

9 

Sing or rap about pi.

2 

Write some pi-inspired poetry. 

You could write down how to write about pi in various languages.

Use the haiku form to write about pi. Or write a piaku, using words with syllables that follow the digits of pi.

Or write a piaphrase, using words with letters following the digits of pi. Some people use this method to memorize pi for some number of digits.

6 

If you're really bored (as the web site says) memorize pi to some impressive amount of digits. No rounding off. If you get good, you can join a club for people who have memorized a hundred digits or more. The world record is over 60,000.

Pioneer Pi Day. Pin a tail on a Pinneped. Pinion pink pions. You won't be pilloried for being picayune. Let me know how it goes.

Curling Rocks!

Last Updated (Tuesday, 23 February 2010 13:33) Written by Raymond Nakamura

Curling challenges the skills and strategies of both players who play it and scientists who study it. The game gets its name from the way curlers add spin to a curling rock so it will curl around other rocks. The curling happens just at the end, when the rock is slowing down. 

The Rock

Also called a stone. The curling rock weighs between 16 and 20 kilograms. This is a video about how it's made from special quartz-free granite found only in Scotland and Wales. The bottom of a curling stone is not flat. It is more like a donut, with a ring upon which it contacts the ice. This reduces the surface area in contact, but increases the weight per unit area. On ice, this pressure raises the temperature of the ice and lowers its frictional coefficient, making it slipperier.

The Ice

Sweeping

Sweeping allows the rock to travel further without curling. A recent study using infrared cameras has found that the sweeping action raises the temperature. It doesn't melt it as some had speculated. Again, raising the ice temperature of the ice lowers its frictional coefficient, so the rock will slide further. I guess in the old days, before the rubbing technique, the brooms helped clean the surface to reduce the friction.

Left-Right Hypotheses 

One explanation for the curl is that as a rock moves forward and rotates, the side where the rotational motion is in the same direction as the overall motion of the rock will move faster than the other side. When the forward motion slows, this difference becomes significant. 

Long-time Flying Circus of Physics guru, Jearl Walker, explained this in a radio interview on the long-time science program Quirks and Quarks, with long-time Canadian science writer Jay Ingram, who wrote a nice chapter on curling science in his Velocity of Honey book.

Mark Denny, a physicist/science writer in BC, has also argued for a left-right difference in ice accumulation, because of a snow plow effect in which bits of ice tend to accumulate on the one side and result in more friction on the slower side as a result. Not to be confused with a rolling stone, which gathers no moss.

The Front-Back Hypothesis

The Ontario Science Centre has a video with a spiel about how an a round object like a drinking glass upside down on a surface, it will curl opposite to a curling rock. The explanation is that as it slows down, the front edge pushes down more and so you get more friction at the front edge (like when you put on the brakes and move forward in a car). The object moves in the direction of the back edge. Try this yourself at home, but I take no responsibility for any broken glass.

Frictional Character

A physics prof at the University of Northern British Columbia, Mark Shegelski says when these forces occur on a curling rock, the increased downward force in the front melts the ice, so it experiences less friction, not more. As a result, the rock moves in the direction of the front edge. As well, a proposed micro-layer of water would get carried around under the ring of the rock and add to the curl.

Final End

We seem to be stuck between a rock and a not-so-hard place. My money would go with the left-right approach, but I'd like to see more evidence to refute one or more of the explanations of how curling rocks curl. Of course, that's easier said than done. If any of you have done some experiments or have other curling insights on this situation, please add them to the comments.

In the meantime, go Canada go!

Digging into Groundhog Day

Last Updated (Tuesday, 09 February 2010 23:05) Written by Raymond Nakamura

My daughter was telling me all about Groundhog Day after kindergarten the other day.  I was thinking what a weird tradition it is, though perhaps it is no weirder than other marketing ploys dressed as traditions this month, like Valentine's Day, Lunar New Year, and of course, the Olympics.

Why do we have Groundhog Day?

In the lower Mainland, we are still waiting for winter to begin, never mind when it will end. In other places though, I suspect it has something to do with the February blahs or Seasonal Affective Disorder.

The first groundhog day took place in 1886, as a kind of media stunt. A newspaper editor orchestrated it in Punxsutawney, Pennsylvannia, home of the most famous meteorologically inclined groundhog, Punxsutawney Phil. 

In Canada, the most famous is Wiarton Willie, based in Ontario. This media stunt began in the 1950s with a fur hat, which was eventually replaced with an albino groundhog. The original Willie died back in 1999 while hibernating and has succeeded by other albino groundhogs. Punxsutawney Phil claims immortality.

Why is it on Feb. 2?

February 2, which is halfway between the astronomical start of winter (Dec. 21), the winter solstice when the night is the longest, and the start of spring (Mar. 21), the vernal equinox, when day and night have become equal.

Earlier celebrations on February 2 include the Celtic celebration Imbolc and the Christian Candlemas, which includes predictions for spring depending on the sun on that day. German settlers brought this custom to America. During the winter, if it's sunny, it's probably cold. Similarly, if a groundhog sees its shadow, winter is supposed to last another six weeks.

Why a Groundhog?

Various animals have been used for weather predictions in Europe including bears, badgers and hedgehogs, often related to their emergence from hibernation. 

Groundhogs (Marmota monax), also known as woodchucks and marmots, also hibernate. They have a wide distribution in North America.

How good are they at predicting the weather?

The accuracy of Canadian groundhogs is about 37% for the past 30 to 40 years. Based on the occurrence of sunny or cloudy days, this did not differ from chance. I could not find any data for paid meteorologists for six week periods. Of course, regardless of whether or not a groundhog sees its shadow, the official start of spring (Mar. 21) is about six weeks away.

Fuel Cells Rush In

Last Updated (Tuesday, 26 January 2010 10:31) Written by Raymond Nakamura

A silver car covered in bubbles passed me on the Burrard Street bridge the other day. On second glance, I realized the bubbles were decals of water molecules. It was a fuel cell car. I thought they were still the stuff of science fiction, but apparently not.

On the Road

I found out that fuel cell cars are here for the Vancouver Olympics. They are using hydrogen to produce electricity to run the motor. Apparently, other fuel cell cars were tested here before. Ballard, a leader in fuel cell technology based in Burnaby, sold off its car projects to focus on other applications as back-up generators and so on.

What's Old is New Again

The idea for fuel cells has been around for over 150 years. They proved themselves in the space program, providing both electricity and water from hydrogen and oxygen.

More than One Way to Skin a Cation

Various kinds fuel cells are being developed now, based on different fuels and ways of extracting electricity from them. The basic idea is that a catalyst takes the electrons from the hydrogen atoms to produce electricity and hooks up the hydrogen ions with oxygen to make water. This part is clean and quiet. The car I saw had four slots in the back with little wisps of what I guess were water droplets coming out.

Bum Rap

Some people associate hydrogen with the Hindenberg blowing up way back when. This rep is not helped by the big explosion of the fuel cells running the desert hotel in the James Bond movie, a Quantum of Solace. Never mind that. Though they do make for louder balloon demos.

Bright Idea

In practise, a greater concern is the distribution of hydrogen. Although hydrogen is the most abundant element in the universe, it tends to be connected with other elements. So you need to use energy to get it on its own. Solar power is clean but not always available. Using the sun to create energy to produce hydrogen can be a convenient way to generate electricity on demand. 

Road Blocks

Besides hydrogen distribution, other challenges for fuel cells is their cost, and ability to function in cold weather.

So keep your eyes out for fuel cell cars — you might not hear them. 
And if you've driven a fuel cell car. please share what it was like.