Christmas science

Science surrounds us with holiday spirit

By Dr. Jon

Maintaining equilibrium Somewhere off in the frigid air I hear the hint of a chuckle and a ho ho ho. Holidays are upon us bringing stress-free snacking and bottomless hot toddies to be sipped around a finely decorated tree. Several pounds of turkey – or possibly Tofurky – will be consumed all in the name of fun and Christmas. Science will not be denied a seat around the dining table this holiday season because as always, it surrounds us, especially at this time of year.

Light emitting diodes (LEDs) are slowly replacing the incandescent variety to fulfill our decorating desires. LEDs are in control everywhere, from street lights to channel surfing, and they work because they’re made of the right stuff. The right stuff happens to come in the form of inorganic semiconducting materials like gallium arsenide and other combinations of aluminum, phosphorous, and indium.

The different combinations of these elements determines which colours we’ll see lighting up the neighbourhood. Semiconductors are often doped to enhance performance, increasing electron flow and light output, just like the doping of home-run-king Barry Bonds increased dinger output to record highs.

Volatile molecules like the vapours given off by mom’s sugar cookies enter the nostrils and travel up to the olfactory epithelium, which is simply a dense patch of cells including sensitive nerve cells. These neurons connect our smellers directly to the brain, firing signals when distinct Christmas smells waft on up the nasal passages.

The smell of Christmas often transports us to the simpler times in life: Waiting for Santa, wishing for snow, and flat out playing as hard as you could. For others a certain aroma instantly triggers thoughts of unhappier moments we’d rather forget. Olfaction is a powerful mnemonic device, triggering memories with much greater efficiency than our other senses. When studying for final exams some carefully placed essential oils next to those incredibly hard-to-remember definitions might just do the trick.

Whether you put the finishing touches on the bushiest of firs, or a Charlie Brownian twig, the tree itself is a constant reminder of nature’s adaptability. Trees need to transport bucketfuls of water over large vertical distances to hydrate their leaves. Lifting all that water is no easy task, especially for a 100 metre redwood, but it’s accomplished through a process known as transpiration pull.

A tree has plumbing just like a house, but the pipes are tiny tubes called xylem. As evaporation occurs through the tiny pores in a tree’s leaves the strong cohesive force between water molecules pulls more molecules up through the skinny pipes. The waxy needles of a Christmas tree allow it to reduce the amount of evaporation, thus conserving water in drier climates. The physical process of transpiration is a tree’s ticket to the sky.

Whether you celebrate Christmas, Hanukkah, Kwanzaa, or another holiday you’re bound to come across some fine examples of science in your traditions. Even Frank Costanza’s celebration of Festivus embraces chemistry (the aluminum pole) and biomechanics (feats of strength). However, science is at a loss when it comes to immaculate conception, Festivus miracles, flying reindeer, and Santa squeezing his oversized belly into an undersized chimney. There are some things science simply cannot explain.

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