February 2, 2010

Groundhog Day—U.S. and Canada

This holiday pro
bably evolved from Imbolc and Candlemas (see yesterday's post). According to folklore, if a groundhog coming out of its burrow on this day sees its shadow, it will go back into its burrow, and winter will continue for six more weeks. On the other hand, if the groundhog does not see its shadow, it will leave the burrow; this means that spring will come early.

Some towns hold early-morning festivals to watch the groundhog emerge from its burrow. There are also speeches, skits, and food. The largest celebration is held in Punxsutawney, Pennsylvania. There as many as 40,000 people gather; the town has been observing Groundhog Day since at least 1886.

Groundhog Day became a lot more famous upon the release of the movie by the same name. Released in 1993 and starrin
g Bill Murray, this movie is about a television weatherman is forced to relive one particular Groundhog Day over and over again until he learns to become a better person.

Studies in both Canada and the U.S. show that the groundhog-shadow method of prediction is accurate between 37 and 39% of the time. (Of course, astronomically speaking, if the first day of spring is the vernal equinox, spring never “comes early”; however, this folk custom is more about weather than about the length of day and night or other astronomical phenomena. So these measures about “accuracy” speak to whether the weather w
ill get more mild as the vernal equinox approaches, or if it will stay cold and stormy.)

It seems to me that, with just two settings (“6 more weeks of winter” or “early spring”), a prediction made by flipping a coin would be just as accurate, depending I suppose on the location and its general climate pattern. Don't you agree?


Watch Groundhog Day.

I love this movie! It's fun, funny AND deep and philosophical!

Predictions and Prophecies

It is important for people to be able to predict the weather. Farmers, in particular, need to know when to plant to avoid seedling-killing frosts, for example, or when rain is likely or unlikely to fall.

For centuries people have tried to predict the weather, and a certain am
ount of observation-based wisdom informed various folklores. However, some superstitions that are based on no evidence at all have developed, as well.

Unfortunately, climate systems and weather are complex enough to stymie, to some extent, even modern scientific predictions. Even though humans now have much more accurate data about climate and weather from around the world, as well as a much better understanding of how air pressure, moisture, and temperature interact to create a wide variety of weather phenomena, the chaotic nature of the atmosphere and the difficulty in understanding all the factors involved in meteorology means that it is hard to predict weather with certainty. Also, the longer the forecast (such as predicting the weather a week from now rather than tomorrow's forecast), the much more uncertain it is.

Some scientists working in other fields, however, can make EXCELLENT predictions. For example, astronomers have been able to predict eclipses and comet appearances quite precisely for years and decades, even centuries. Neptune and Pluto were di
scovered based on mathematical predictions that told astronomers to look for them—and also where to look.

Predicting what will happen in an experiment can be an important step, because then the experimenter can look for evidence that confirms or refutes the prediction.

Predicting what will happen in a card game can be very important. Ditto chess, football, and many other games and sports.


Predicting what goods and services people will buy, and at what price, is an important step in building a business. Economists try to predict general trends of buying, saving, investing
, and selling in helping to eliminate inflation or to manage recessions, as well. Economic patterns are quite possibly harder to predict than weather patterns!

Futurists study the current situation, the technologies that are being developed, trends, population growth and migrations, and the scientific theories that are just beginning to emerge in labs. From all of that data and using their own expertise, futurists make predictions about the future. How accurate the predictions are depends mostly on how good the data is and how “expert” the futurist is, but it also depends a bit on luck and happenstance. Arthur C. Clarke, a scientist and science fiction writer, predicted satellites in geo-stationary orbits (which we have) and lunar colonies (which we don't have...yet).


Some people say that making predictions is a mystical activity based on supernatural beliefs, but I think the word prophecy goes better with that sort of thing. Predictions can be very rational, science-based, math-based, evidence-based.

Is YouTube's “The Prediction” magic?

Try this YouTube video from Richard Wiseman's Quirkology. Is it a mathematical or magical trick?
Watch “The Solution” to see the answer if you cannot figure it out on your own... (Notice, whoever made that answering video seems to think that a mathematical “forecast” is NOT a prediction. I disagree!)

Invent a number prediction trick.

Here's an example...See if you can figure out how it works...then invent your own.
  • Think of a number between 1 and 9.
  • Double it.
  • Add 5.
  • Subtract 3.
  • Add 4.
  • Divide by 2.
  • Subtract the number you started with...
  • And your answer is...[fanfare]...3.
Here is a more complicated number-prediction trick—meant for a calculator!

Learn a card prediction trick.
Or two...or three...

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