University of Wisconsin – Madison Materials Research Science and Engineering Center

1. Try This! Try This! • To make your own iridescence, try this art project. You will need: • Black construction paper • Small shallow pan • Water • Clear nail polish • Cut the black paper into 2” x 2” squares. • Completely submerge the paper in the water. • Drip one drop of nail polish onto the center of the water. (NOT on the paper.) The nail polish will form a thin layer on the surface. • Lift paper out of the water and the film will stick. Allow paper to dry. • What do you see? How does a clear • substance do this? What is going on? • To make your own iridescence, try this art project. You will need: • Black construction paper • Small shallow pan • Water • Clear nail polish • Cut the black paper into 2” x 2” squares. • Completely submerge the paper in the water. • Drip one drop of nail polish onto the center of the water. (NOT on the paper.) The nail polish will form a thin layer on the surface. • Lift paper out of the water and the film will stick. Allow paper to dry. • What do you see? How does a clear • substance do this? What is going on? University of Wisconsin – Madison Materials Research Science and Engineering Center University of Wisconsin – Madison Materials Research Science and Engineering Center Try This! Try This! • To make your own iridescence, try this art project. You will need: • Black construction paper • Small shallow pan • Water • Clear nail polish • Cut the black paper into 2” x 2” squares. • Completely submerge the paper in the water. • Drip one drop of nail polish onto the center of the water. (NOT on the paper.) The nail polish will form a thin layer on the surface. • Lift paper out of the water and the film will stick. Allow paper to dry. • What do you see? How does a clear • substance do this? What is going on? • To make your own iridescence, try this art project. You will need: • Black construction paper • Small shallow pan • Water • Clear nail polish • Cut the black paper into 2” x 2” squares. • Completely submerge the paper in the water. • Drip one drop of nail polish onto the center of the water. (NOT on the paper.) The nail polish will form a thin layer on the surface. • Lift paper out of the water and the film will stick. Allow paper to dry. • What do you see? How does a clear • substance do this? What is going on? University of Wisconsin – Madison Materials Research Science and Engineering Center University of Wisconsin – Madison Materials Research Science and Engineering Center

2. Iridescence Iridescence In the activity, the nail polish spreads out into a very, very thin film, only a few hundred nanometers thick—similar to a In the activity, the nail polish spreads out into a very, very thin film, only a few hundred nanometers thick—similar to a soap bubble! The thickness of the bubble film varies throughout the film. Because the thickness changes, some interesting things happen when light strikes the bubble. White light is a mixture of all colors. Some wavelengths (colors) hit both the top and bottom of the film and remain “in sync” or “in phase” to make bright colors of pink, blue, etc. This is called constructive interference. Other wavelengths get “out of phase,” referred to as destructive interference, and these colors get canceled out. Together, both types of interference result in iridescence. soap bubble! The thickness of the bubble film varies throughout the film. Because the thickness changes, some interesting things happen when light strikes the bubble. White light is a mixture of all colors. Some wavelengths (colors) hit both the top and bottom of the film and remain “in sync” or “in phase” to make bright colors of pink, blue, etc. This is called constructive interference. Other wavelengths get “out of phase,” referred to as destructive interference, and these colors get canceled out. Together, both types of interference result in iridescence. Iridescence can also be seen in nature, with repeated layers of nanostructured surfaces rather than thin films. The Blue Morpho butterfly is one example. (See right. Bottom picture is a microscope image of the wing.) Scientists have borrowed this idea from nature (biomimicry) as inspiration Iridescence can also be seen in nature, with repeated layers of nanostructured surfaces rather than thin films. The Blue Morpho butterfly is one example. (See right. Bottom picture is a microscope image of the wing.) Scientists have borrowed this idea from nature (biomimicry) as inspiration for new products, including security images on currency/credit cards, sensors, and fabrics. for new products, including security images on currency/credit cards, sensors, and fabrics. Activity and text adapted from Dragonfly TV. www.pbskids.org/dragonflytv Activity and text adapted from Dragonfly TV. www.pbskids.org/dragonflytv Iridescence Iridescence In the activity, the nail polish spreads out into a very, very thin film, only a few hundred nanometers thick—similar to a In the activity, the nail polish spreads out into a very, very thin film, only a few hundred nanometers thick—similar to a soap bubble! The thickness of the bubble film varies throughout the film. Because the thickness changes, some interesting things happen when light strikes the bubble. White light is a mixture of all colors. Some wavelengths (colors) hit both the top and bottom of the film and remain “in sync” or “in phase” to make bright colors of pink, blue, etc. This is called constructive interference. Other wavelengths get “out of phase,” referred to as destructive interference, and these colors get canceled out. Together, both types of interference result in iridescence. soap bubble! The thickness of the bubble film varies throughout the film. Because the thickness changes, some interesting things happen when light strikes the bubble. White light is a mixture of all colors. Some wavelengths (colors) hit both the top and bottom of the film and remain “in sync” or “in phase” to make bright colors of pink, blue, etc. This is called constructive interference. Other wavelengths get “out of phase,” referred to as destructive interference, and these colors get canceled out. Together, both types of interference result in iridescence. Iridescence can also be seen in nature, with repeated layers of nanostructured surfaces rather than thin films. The Blue Morpho butterfly is one example. (See right. Bottom picture is a microscope image of the wing.) Scientists have borrowed this idea from nature (biomimicry) as inspiration Iridescence can also be seen in nature, with repeated layers of nanostructured surfaces rather than thin films. The Blue Morpho butterfly is one example. (See right. Bottom picture is a microscope image of the wing.) Scientists have borrowed this idea from nature (biomimicry) as inspiration for new products, including security images on currency/credit cards, sensors, and fabrics. for new products, including security images on currency/credit cards, sensors, and fabrics. Activity and text adapted from Dragonfly TV. www.pbskids.org/dragonflytv Activity and text adapted from Dragonfly TV. www.pbskids.org/dragonflytv