![]() ![]() The material only glows when it is exposed to certain wavelengths of incoming light.Ģ. In your own words, what is fluorescence? And what conditions must be met for a fluorescent material to glow?įluorescence happens when an atom or molecule absorbs light at one wavelength and then emits light, typically at a longer wavelength. Then read the Science News article “ Many frogs glow in blue light, and it may be a secret, eerie language” and discuss the second set of questions with a partner.ġ. Read the Science News Explores article “ Scientists Say: Fluorescence” and answer the first set of questions individually. Encourage students to use their observations to form their hypotheses. As an optional assessment at the end of this lesson plan, ask students to explain why they can see the message under ultraviolet light, but can’t see it well in normal light. ![]() Ask students to take detailed observations. ![]() Then, write a “hidden message” to your class in a yellow highlighter on a yellow sheet of paper. Consider using turmeric root in water, tonic water with quinine, honey, or liquid laundry detergent. Use a black light to do a few demos with common fluorescent materials. Some examples of luminescence include highlighters, glow-in-the-dark materials, and brightening agents in some laundry detergents. Luminescence also includes light produced when chemical reactions excite electrons (chemiluminescence). Fluorescence is one type of luminescence called photoluminescence, or the emission of light caused by the decay of electrons excited by incident light. Biofluorescence happens when an organism absorbs light and emits it at a different wavelength, whereas bioluminescence refers to a chemical or biological reaction that happens within an organism regardless of an external light source.Īsk students to name things they know of that “glow” by fluorescing. Note: If students choose to do the extension, review the differences between bioluminescence and biofluorescence. End with an extension question that will allow students to do research on the evolutionary purpose of fluorescence and its application in industry. Then, have students read the Science News article“ Many frogs glow in blue light, and it may be a secret, eerie language” and discuss the second set of questions with a partner. Ask students to read the Science News Explores article “ Scientists Say: Fluorescence” and answer the first set of questions individually. Start with a teacher-led demo on fluorescence. Fluorescence is an example of absorption: light hits an object, it is absorbed, and then light at a longer wavelength is emitted. These interactions can include reflection, refraction, absorption, transmission, polarization, diffraction and scattering. You should also review how light can interact with objects, which depends on an object’s composition and the wavelength of incident light. Check out “ Exploring electromagnetic radiation” for a lesson plan. They should understand how properties of light, including wavelength, frequency and energy, vary across the electromagnetic spectrum. Before beginning this activity, students should be introduced to light and electromagnetic radiation. ![]()
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