Clear Sunscreen: How Light Interacts with Matter
- Subject:
- Science and Technology
- Institution Name:
- National Center for Learning and Teaching
- Collection:
- National Center for Learning and Teaching
- Grade Level:
- Secondary
- Abstract:
This unit explores issues related to size and scale, specifically the effect of the size of nanopowders on the interactions of energy and matter (e.g., the absorption of light, addressing the electromagnetic spectrum and associated wavelengths). For example, old sunscreens use "large" zinc oxide particles, which block ultraviolet light but scatter visible light, giving the cream a white color. If nanopowders of zinc oxide are used instead, the cream is transparent, because the diameter of each nanoparticle is smaller than the wavelength of visible light. Upon completing this unit, students will understand: How the energies of different wavelengths of light interact differently with different kinds of matter; Why particle size can affect the optical properties of a material; That there may be health issues for nanosized particles that are undetermined at this time; That it is possible to engineer useful materials with an incomplete understanding of their properties; There are often multiple valid theoretical explanations for experimental data; to find out which one works best, additional experiments are required; How to apply their scientific knowledge to be an informed consumer of chemical products. Length: 5 lessons, up to 11 50-minute classroom periods if all lessons are used. Not all lessons are required. Use the lessons most appropriate for your students.
- Course Type:
- Learning Module
- Languages:
- English
- Material Type:
- Activities and Labs, Assessments, Curriculum Standards, Lecture Notes, Lesson Plans
- Media Format:
- Downloadable docs
- Conditions of Use:
-
Creative Commons Attribution 3.0
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