Cold and Warm Light Mirrors
Without protection, the lamp in a slide projector would melt the valuable slide. How can you protect the slides? This exhibit shows the effect of different coatings on glass plates. One coating allows heat to pass through the glass plate (long-wave infrared radiation) but reflects most visible light (short-wave radiation). The other coating allows light to pass through but reflects heat - This is what a projector needs. Come and feel the difference.

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