In a world where bigger is often better, microcards might make you rethink all that you knew about Christmas cards and what is trendy. Sure, you have the always trendy singing Christmas cards, the DIY light up cards, and the new diamond painting cards, but have you heard of nano Christmas cards? That’s right, nano Christmas cards. These cards are so small they are measured in microns, or millionths of a meter, which makes them invisible to the naked eye. At roughly 15 microns wide and 20 microns tall, you need a microscope to read them. Sounds a bit James Bondish meets Dr. Frankenstein, to me. To further illuminate how small these cards really are, you will need 200 million cards to cover the surface of a single postage stamp. That's a lot of tiny cards!The world’s smallest Christmas card was a project of UK’s National Physical Laboratory (NPL). Researchers at the lab used a silicon nitride membrane with a thin platinum layer to create the card. A simple snowman along with the messages “Season’s Greetings” was etched onto the front of the card and “From NPL” was etched the inside of the card using a focused ion beam. How does this etching process work? The beam guides a stream of fast-flowing charged particles across the card’s surface, causing the participles to etch the surface where directed. This is not just about a fun way to celebrate Christmas, this is about research that enables engineers to create objects on a small scale. These tiny objects may improve techniques or process throughout the fields of medicine, computing, and mechanical engineering. For example, the tools used to create the nano card now helps the research team at NPL to improve battery powered and semiconductor technologies.Although you are probably just hearing about this microtechnology now, scientists and engineers have been researching methods to create small objects that perform tiny tasks for over ten years now. They have been able to come up with the inchworm-like microbot, a 250 micron long, functioning robot. There is also the world’s smallest hot-rod that is 50,000 times smaller than a human hair and has been dubbed, the “nanodragster.”Then there are the molecular scissors that are 3 nanometers in length and are light-activated. Three scientists won the Nobel Prize in Chemistry for building the world’s smallest machines using molecules that link together into a device that moves little objects.The NPL team also have had some experience in nanotechnology prior to the tiny Christmas card. In 2009, researchers at NPL created a “nano snowman” comprising tiny beads that calibrate lenses in electron microscopes. Their micro sculpture measured 10 microns wide and was pieced together by manipulating nanometer particles and then was glued together using platinum. The itty bitty details like the snowman’s eyes and smile were carved on the sculpture using a similar ion beam technology they used in their most recent project, the snowman Christmas card. Talk about needing to pay attention to small details!To learn more about the world’s smallest Christmas card, check out this video. [embed]https://www.youtube.com/watch?v=IecDiwKDOFs[/embed]