We all heard the legends as kids –– ships sunk from carrying too much gold, lending lessons in greed.
But Swiss researchers might have just made all those lessons obsolete after creating a foam made of genuine gold. It's so light, it can float on top of a cappuccino's foam.
The researchers published their discovery in the journal Advanced Materials. What they created is 1,000 times lighter than gold's usual form because it's 98 percent air.
To make the material, the researchers heated milk proteins to make protein fibers a nanometer-thick and then put them in a solution of gold salt to crystallize together.
The clear block you see is the protein without any gold. The red block has gold added, just smaller particles than the gold image in the middle.
Having the gold particles crystallize while the protein structure was created instead of injecting them afterward is a cutting-edge technique.
The lead researcher said in a university release, "One of the big challenges was how to dry this fine network without destroying it."
You might be wondering why the world needs really light gold. As it turns out, the researchers say jewelry is just one possible application.
The gold's porosity and large surface area make it highly efficient for many chemical reactions that require the presence of gold.
This video includes images from frau-Vogel / CC BY ND 2.0.