1. Reflectance Spectroscopy Lab

2. Different colors correspond to different wavelengths of visible light 665 nm 630 nm 600 nm 550 nm 470 nm 425 nm 400 nm

3. Today’s Lab If we shine light on an object, some light is absorbed and some is reflected Which wavelengths/colors are absorbed versus reflected?

4. Incoming white light (all colors )

5. White paper Incoming white light (all colors )

6. White paper White paper reflects all wavelengths Incoming white light (all colors )

7. Black Paper Incoming white light (all colors ) Absorbs all wavelengths

8. Green Paper Reflects green light Incoming white light (all colors ) Absorbs other colors

9. Objects appear to be different colors because of the light they reflect

10. Reflected light versus emitted light

12. Today’s Lab

13. Spectrum: a plot that shows how reflected light from an object varies with wavelength

15. Different objects have unique spectra

16. Reflectance Spectrometer Shines a single wavelength of light on an object and measures intensity of reflected light

17. Reflectance Spectrometer Has 2 infrared channels

18. Infrared light has longer wavelength than red light Can think of infrared energy as the heat an object emits Humans emit infrared energy Planets emit infrared energy