Fluorescence: Molecular Tagging

Interactive model, with minimal support

Overview and Learning Objectives

Fluorescence has many applications in lighting, mineralogy, and biochemistry. When fluorescent chemical groups can be attached to other molecules, they can easily be detected. In this activity students will explore how fluorescence works and its potential uses.

Students will be able to:

Understand that an atom or molecule in a ground state can absorb one photon and return to the ground state in two steps, first emitting a photon to fall into an intermediate state.

Recognize that an atom or molecule with this property is called fluorescent.

Explain why the emitted photon will have less energy than the absorbed one.

Understand that it is possible that you cannot see the first photon because it is UV, but can see one of the emitted ones because they are in the visible.

Recognize that this is called fluorescence.

Describe how a molecule can be tagged with a fluorescent molecule.

Explain the value of fluorescent tagging in tracking a molecule.

return to top

Assessment

Test

http://www.concord.org/~barbara/workbench_web/pdf/Fluorescence_Assess.8.07.pdf

Rubric

http://www.concord.org/~barbara/workbench_web/pdf/Fluorescence_Rubric.8.07.pdf

return to top

Central Concepts

Key Concept:

Fluorescence is glow produced when electrons, which have absorbed energy from a source like ultraviolet (UV) light and have gone to a higher orbital, sink back to a lower orbital, releasing most of the absorbed energy as light of a longer wavelength. Fluorescence has many applications in lighting, mineralogy, and biochemistry. When fluorescent chemical groups can be attached to other molecules, they can easily be detected. In this activity students will explore how fluorescence works and its potential uses.

Additional Related Concepts

Physics/Chemistry

• Light-Matter Interaction
• Photon

return to top

Benchmarks and Standards

NSES

• Physical-Science: Energy/Matter Interactions - 1 Waves, including sound and seismic waves, waves on water, and light waves, have energy and can transfer energy when they interact with matter (Full Text of Standard)
  
  
• Physical-Science: Energy/Matter Interactions - 3 Each kind of atom or molecule can gain or lose energy only in particular discrete amounts (Full Text of Standard)
  
  

return to top

Extensions and Connections

• This activity logically follows the activity introducing Light-Matter Interaction.
• This Flash animation allows manipulation of an electron in both Bohr and an Orbital models.

http://www.concord.org/~btinker/workbench_web/light_matter.swf

Green Fluorescent Proteins

return to top

Activity Credits

Created by CC: Molecular Literacy using Molecular Workbench

return to top

Requirements

• Java 1.5+ - Java 1.5+ is available for Windows, Linux, and Mac OS X 10.4 and greater. If you are using Mac OS X 10.3, you can download MW Version 1.3 and explore within it instead.

return to top