Friday, 21 February 2014 14:39

## N1-07: VARIATION OF SPECTRUM WITH LAMP INTENSITY

• ID Code: N1-07
• Purpose: Demonstrate continuous spectrum as the brightness of the source changes
• Description:
A bright white light source is directed through a series of lenses and a prism to provide a continuous white light spectrum. The intensity of the source bulb is adjusted using a variable transformer on the input to the light source.
##### Engagement Suggestion
• Encourage students to predict how changing the input power will change the spectrum. Will the spectrum grow uniformly brighter and dimmer, or will there be a change in what colors we see in what proportions?
##### Background
As the light intensity is decreased, the spectrum becomes less intense but also shifts significantly toward the red. Increasing the source intensity, and thus the blackbody temperature, shifts the spectrum to the blue as the intensity increases.
• Availability: Primary demonstration apparatus being repaired, but substitute apparatus available.
• Loc codes: OM1, LS1, PS1, FS0

• #### N1-03: PRISMATIC SPECTRUM OF WHITE LIGHT - WATER PRISM

Demonstrate continuous spectrum using water as the dispersing medium. Read More

• #### N1-06: POLYPRISM SPECTRA

Demonstrate continuous spectra with several different types of glass. Read More
• #### N1-07: VARIATION OF SPECTRUM WITH LAMP INTENSITY

Demonstrate continuous spectrum as the brightness of the source changes Read More
• #### N1-08: GOETHE'S PUZZLE

Show the view of a slide through a prism and argue about color theory. Read More
• #### N1-09: COMPLEMENTARY SPECTRUM

Display the spectrum of a "negative" slit. Read More

• #### N1-12: DIFFRACTION SPECTRA - GRATING ON OVERHEAD PROJECTOR

Very simple white light diffraction spectrum. Read More
• #### N1-13: DIFFRACTION SPECTRUM OF WHITE LIGHT - PORTABLE

Individual observation of white light spectrum. Read More
• #### N1-14: REFLECTION GRATING - LARGE

Show a spectrum from a small bright source. Read More
• #### N1-21: COLOR SEPARATION AND RECOMBINATION BY PRISMS

Show how a prism can recombine previously dispersed white light. Read More
• #### N1-22: OPTICAL BOARD - PRISMS - SEPARATE AND RECOMBINE

Separate white light into its component colors with a prism and use an identical prism to recombine the light. Read More
• #### N1-23: FINE RESOLUTION OF SPECTRUM USING TWO PRISMS

Increase the dispersion in a white light spectrum by adding a second prism. Read More
• #### N1-31: SUN DOG - MODEL

Show how a "sun dog" is formed. Read More
• #### N1-32: ICE CRYSTALS - PAPER MODELS

Illustrate how two types of ice crystals formed high in the atmosphere float downward through the air with preferred orientations. Read More
• #### N1-41: RAINDROP RAY MODEL

Illustrate formation of a rainbow. Read More
• #### N1-42: RAINDROP MECHANICAL MODEL

Illustrate rays in formation of a rainbow. Read More
• #### N1-43: RAINBOW - GLASS BEAD MODEL

Observe an almost complete circular rainbow formed by glass beads. Read More
• #### N1-44: OPTICAL BOARD - RAINBOW

Demonstrates internal reflection and dispersion of light Read More
• #### N1-45: RAINBOW - WATER FLASK

Demonstrate a large angle rainbow. Read More