LEDs or light emitting diodes are everywhere from traffic lights to Christmas ornaments to remote controls.  Inside these tiny bulbs is a small grey block which is made of silicon. And, silicon has the unusual origin of coming from sand.

Sand is melted and purified and then cast in long thick logs, called ingots, which are slice like baloney. Twenty years ago, these logs used to be as thick as a thumb, now these logs are wider than dinner plates.  The slice is then cut into small square chips.

The chips are then given a bit of phosphorus on one side and a bit of boron on the other. Phosphorous is an element that has more electrons than silicon; boron has fewer electrons than silicon. These different sides are connected to a battery. The battery pushes electrons from the phosphorous side to the boron side. And, when these electrons connect with atoms that don’t have electrons, light is given off.

LEDs are more efficient than incandescent bulbs. Incandescent bulbs, the ones we attribute to Thomas Edison, give off lots of heat. This is why toy oven use these bulbs to bake small cakes.  In fact, 70 percent of the energy used by incandescent bulbs is heat. That’s wasted energy.

But, LEDs run cool. They are so cool that cities now must remove snow from LED traffic lights during the winter. In the past, incandescent bulbs ran so hot, they would burn off any snow that landed on them. LEDs are not running hot and so snow collects on traffic lights. (This happens when you solve one problem, you inherit another one.)

So, as you can see, small bits of beach sand purified into silicon are made into sandwiches that give off light. Now, this is a bright idea.

 

Additional reading & activites (Affiliate Links):

Elements: A Visual Exploration 

Snap Electronics Fun LED kit

Materials: A Very Short Introduction

There is lots of news about CTE or chronic traumatic encephalopathy. CTE is a brain disease, a neurological degenerative disease that is caused by repetitive hits to the head. The symptoms include dementia, memory loss, and depression. In the early twentieth century, this condition was called “punch-drunk” and was found in a number of boxers who ultimately were found to suffer from dementia. No cure for CTE is currently known, and at present it can only be identified postmortem.

Here is an excerpt from Newtons Football (Affiliate Link), which describes where doctors are:

In the field of head injuries, scientists have a lot to try to understand as they parse the puzzle of concussions and the related long-term degenerative brain disease known as chronic traumatic encephalopathy, or CTE.
Just how does a concussive impact impair the function of the brain?

“You’ve got this metabolic crisis going on within the cell,” posits Robert Cantu, a professor of neurology at Boston University, as potassium ions flood out of the nerve cell, replaced by calcium ions, which prevent the cell from passing on information.”

Is there a genetic component to concussions and CTE?

“No one knows yet, but studies are focused on a variant of a common lipid transport gene called ApoE-e4. This gene does good things making sure fat goes to the right place,” says Robert Stern, a professor of neurology at Boston University, “but if you have the wrong form it does something crazy in the brain.” He adds that “it is a susceptibility gene, as opposed to a deterministic gene. If you have the wrong form, it increases your risk of having the disease, but it does not mean you will get it,” Stern explains. “There is not going to be a CTE gene because it is such a multifaceted disease.”

 

Newtons Football (Affiliate Link)

The secret to the snowflake’s shape can be found in a stack of oranges.

If you go over to the grocery store and head over to the produce section, you’ll find that oranges are stacked up in a way that each orange is touching six other oranges. This arrangement is called a hexagon–it has six sides.  Honeycombs have this hexagonal shape. So do bath tiles.

Oranges in a hexagon shape

Oranges are arranged so that each orange touches six other oranges–a hexagon. Source: Shutterstock

Water molecules stack up just like the oranges, which is why snowflakes have six points to them.  The water molecules collect on a small piece of ice or dust in a cloud and build out just like the oranges to create 6 sides. It takes about 100,000 water droplets to eventually make one snowflake.

What you might not know is that snowflakes have other shapes too.  One looks like a spool of thread, another looks like a pencil. Scientists are still trying to find out how each is made.

Where there is no mystery is how beautiful snowflakes are and how much collaboration it takes for water molecules to create a flake that lands on your tongue.

Find you more about snowflakes here (Affiliate links):

Snowflakes by Ken Libbrecht (featured in the podcast)

Snowflakes in Photographs (picture book of real snowflakes)

Snowflake Bentley (The man who photographed snowflakes)

 

There’s no papering over the impact of origami in technology.

What do pizza boxes, paper bags, and fancy napkins have in common? Well, you might have guessed it — origami.

Origami, which means “paper folding,” is everywhere. While some of the oldest pieces of origami have been found in ancient China and origami’s deepest roots are in ancient Japan, origami makes an impact in today’s technology too.

One of the most important uses of origami today is in airbags. Airbags are doughnut-shape nylon bags that are deployed in a fraction of a second during a car collision. Airbags lie flat inside of the steering wheel. So, engineers needed to find the way to fold an airbag so it will store flat and expand out quickly. They consulted origami artist Robert Lang for the folding recipes. He found the origami folds for making a box with lots of corners was the solution that was needed.

Download some cool origami structures from this website (Used with permission)

http://www.origamiusa.org/diagrams

Origami doesn’t stop there. The National Science Foundation, one of the government’s largest funding sources for research, has funded 13 grants last year to use origami in industry. Origami is being applied to foldable forceps to expanding solar panels to deployable antennas.

Interestingly, other cultures also have a history of folded paper. There are elaborate folded patterns in Europe and folded paper in Mesoamerica going back over a thousand years.

Today, schools are using origami in STEAM education to improve students’ skills. Origami has been found to increase thinking skills, improve geometry learning, and enhance problem solving.

Origami is used in nature. Bugs fold wings with origami patterns; leaf buds have patterns that are similar to Japanese fans. Even molecules are arranged like origami structures.

So, get a piece of paper out and make some folds. Be connected by using this technique that has made impact in so many ways and for so long.

 

Here are some fun books on origami (Affiliate Links):

Robert Lang’s Complete Book of Origami (featured in the podcast)

Star Wars Origami 

Origami Fun Kit for Beginners

The colors come from their skin playing with light.

Chameleons have the ability to change the color of their skin. And, researchers at the University of Geneva have uncovered the secret.

The chameleon’s skin is made up of two layers. The bottom layer is yellow. The top layer has tiny crystals inside it that play with light.

When the male chameleon is relaxed, the crystals in the top layer of the skin are close together. White light, which contains all the colors of the rainbow, shines onto the skin, but only blue bounces back from the top layer. This color combines with the yellow color from the bottom layer to make green.

This phenomenon of creating colors with patterns is what scientists call structural color. Structural color is pretty common in the animal kingdom. Many insects (beetles and butterflies) and birds (peacocks) create color this way. Light shines onto the patterns and only certain colors come off. You can think of the skin as tiny mirrors that select the colors that will be seen.

Structural color occurs in everyday life too. If you look at a soap bubble, you’ll see hints of color. Or if you look at the bottom of a CD, you’ll see hints of color too. Both the soap bubbles and CDs are clear, but the patterns that are on their surfaces play with light to create color. Next time you are at the gas station and see oil on the ground, you’ll see bands of color. This is structural color at work too as the film goes from thick to thin.

When the male chameleon gets angry or wants to attract a mate, it changes the distance between the crystals in its skin. This time when white light shines on the skin, only red bounces back. And that red color combines with the yellow from the first layer to make orange.

Interestingly, the tiny crystals in the skin are too small to see with the human eye. They are a nanometer in size. A nanometer is equal to one-one hundred thousandths of your hair. To find them, researchers had to take a small sample of the chameleon’s skin and measure it with a special microscope. Scientists took samples when the chameleon was relaxed and then again when it was agitated.

Now, researchers are now trying to find out how chameleons know the change the distance between the crystals. And, engineers want to use these patterns to make computer screens with less glare.

What there is no camouflaging is how clever chameleons are.