THIS IS A BUTTERFLY! (Scanning Electron Microscope) - Part 2 - Smarter Every Day 105

TL;DR

Butterfly “pixie dust” is made of scales that detach from small, hollow stumps on the wings through normal wear, including aerodynamic drag. At Georgia State University, Dr Simmons uses a scanning electron microscope to reveal how these scales attach and how their nanostructures manipulate visible light to produce blue and green appearances. Read on to see how electron imaging, false color, and a 60% gold coating expose the wings’ hidden architecture.

Transcript

[music] Hey it's me Destin. Welcome back to Smarter Every Day. I am crossing the street in Atlanta Georgia, you can see the dome in the background and I'm at Georgia State University and I've got a box of butterfly wings. I'm trying to unravel a mystery that I uncovered in the rainforest. We discovered that when we dropped a butterfly and he starte... Read More

Key Insights

• 🙂 Butterfly wings have scales with intricate nanostructures that interact with light to create vibrant colors.
• 😘 Scanning electron microscopes are instrumental in studying the structure of butterfly wings and their scales.
• 🙂 The colors we see on butterfly wings are often not their true colors and are a result of interactions with light.

Questions & Answers

Q: What is the “pixie dust” that comes off butterfly wings?

The dust particles are scales that come off the butterfly’s wings. They can be shed through normal wear and tear, including aerodynamic drag along the wings.

Q: How are scales attached to butterfly wings?

The scales attach to small, hollow stumps arranged in evenly spaced rows on the wing. Normal wear can pluck the scales from these attachment points.

Q: How does a scanning electron microscope create an image of a butterfly wing?

A flow of electrons passes through electromagnetic lenses and scans across the wing. An electron detector measures the secondary electrons emitted from different points, and the signals are filtered to create a grayscale image.

Q: Why must butterfly wings be coated before scanning electron microscopy?

Butterfly wings are insulators, so electron bombardment creates a charge difference that must be discharged to ground. The researchers coat the wings with 60% gold and 40% palladium to provide a conductive path.

Q: Does a scanning electron microscope show the real colors of butterfly wings?

No, the microscope uses electrons instead of light, so it cannot provide color. Scientists commonly add false color to the grayscale images to help viewers understand the structures shown.

Q: How does a morpho butterfly wing appear blue?

The blue scales contain ridges whose measured width matches the wavelength of yellow light. Their baffled nanostructure interacts with visible light and strips out yellow, leaving the wing looking blue.

Q: How does the goliath birdwing butterfly appear green?

Its baffled nanostructures strip out red and blue from incoming light. The remaining light makes the butterfly appear green.

Q: What happens when the wing’s nanostructures are filled with isoproponol?

The wing loses its irradiance when isoproponol fills the nanostructures and prevents them from interacting with light. As soon as the liquid evaporates, the brilliant colors return.

Summary & Key Takeaways

• Researchers at Georgia State University used scanning electron microscopes to study the structure of butterfly wings and the scales that give them color.

• They discovered that the scales on butterfly wings have a complex nanostructure that interacts with light to create colors, such as blue and green.

• The scales are attached to the wings through small, hollow stumps, which can be worn away through normal wear and tear.