Australasian Science: Australia's authority on science since 1938

Take a Closer Look at that Christmas Card

By Magdeline Lum

Many Christmas cards and decorations have incorrect depictions of the Moon and snowflakes.

It’s that time of year when houses are adorned with twinkling lights and decorations with presents under a tree are waiting to be opened. Christmas is approaching. How much attention do you pay to pictures on the Christmas cards you receive or to the paper wrapped around the presents?

You probably don’t worry about it as much as Dr Peter Barthel, an astronomer at the University of Groningen in The Netherlands who found in 2011 that Christmas cards and gift wrapping often depicted the Moon incorrectly. Barthel was spurred into analysis after noticing a UNICEF Christmas card and a popular Advent e-calendar showing an unlikely moonlit scenario.

The scene on the front of the card showed children decorating a Christmas tree beneath a waning Moon crescent, and the calendar also showed carolers under a waning Moon. However, the waning Moon does not rise until 3 am. While it is not impossible for these scenarios to take place, Barthel states that “it’s unlikely” in Communicating Astronomy with the Public.

Barthel examined Christmas books, cards and wrapping paper from The Netherlands and the USA. He found that 40% of pictures in Dutch Christmas books and 65% of Dutch Christmas gift wrap samples incorrectly showed a waning Moon. Artists depicting Christmas scenes in the USA did far better because they usually draw a full Moon with only a few exceptions of waning Moon scenes.

Barthel concludes that the errors are innocent and comparable to incorrectly drawn rainbows with the red band on the inside of the arc.

“Watching beautiful natural phenomena like rainbows and Moon crescents is one thing, but understanding them makes them all the lot more interesting. Moreover, understanding leads to knowledge which lasts,” says Barthel.

Carrying on with the Christmas theme, in 2009 Professor Thomas Koop of the University of Bielefled in Germany wrote a letter to Nature calling on scientists to take a stand against images of four-, five- and eight-sided fake snowflakes. Prof Koop specialises in ice crystal formation.

He turned a blind eye to faux flakes until he observed an octagonal snowflake on Nature’s online advertisement with the caption “…for anyone who loves science”. Snow crystals form when water vapour condenses into ice. Ice crystals grow in a hexagonal rod, a solid flat plane or as a branched crystal depending on the temperature and relative humidity.

Koop points out that the hexagonal shape of snowflakes has been known for at least 400 years when astronomer Johannes Kepler published On the Six-Cornered Snowflake.

“Beautiful photographs abound, including those taken by Vermont farmer Wilson A. Bentley starting in 1885... Why then do many artists invent their own physically unrealistic snow crystals?” Koop asks.

Koop implores the science and design communities to unite in the delight of the natural wonder and beauty of snowflakes. “We who enjoy both science and captivating design should aim to melt away all four-, five- and eight-cornered snow crystals from cards, children’s books and advertisements by enlightening those who unwittingly generate and distribute them.”


How is the holiday season’s “To Do” list looking? Worried about forgetting something? Stop and have a piece of chocolate. It may help your memory.

Flavonoids are chemical compounds that give plants their colours, flavours and scents. These are also the chemical compounds that have been linked to health benefits in humans including antioxidant, anti-inflammatory and antiviral effects. Studies have linked flavonoids to some improvements in the cognitive function of rodents. This has led to suggestions that flavonoids could also lead to the same for humans.

Scientists from the Hotchkiss Brain Institute at the University of Calgary have reported on the effect of epicatechin (a type of flavonoid) on the long-term memory of the great pond snail (Lymnaea stagnalis). Epicatechin is of interest because it is found in cocoa, green tea, red wine and blueberries.

The study of how memory is influenced in humans has proved difficult as memories are influenced by many external factors. The experiences of the snail are better controlled, so it is easier to identify the effect of epicatechin on memory.

Researchers found that when snails were trained over a

30-minute period, the longest memory that lasted was less than 3 hours. When the snails were trained again but with a dosage of epicatechin, they retained their memory for up to 72 hours. These long-term memories were persistent and not easily forgotten.

The mechanism of how epicatechin improves memory is unknown. One theory is that it may protect neurons from oxidative stress. Another theory is that flavonoids increase blood flow to the central nervous system, which has been linked to memory enhancement.

Do we need another reason to have a piece of chocolate?

Merry Christmas!