Element identification
Element ID by spectrography.

Background:

Activity #1 Who am I?:

  1. Take a marker and make a large dot 2cm above the end of the filter paper. Repeat with the other markers.
  2. Place the filter paper so that the end is in the water, but the dots are just above the water.
  3. Wait approximately 20-30 minutes for the water to move up the filter paper.
  4. Compare the different color patterns of the markers with the unknown given to you by the teacher.
  5. Write down the marker that is the closest to the unknown.

Questions:

  • How were you able to identify the correct marker?
  • Was there another marker that was very similar to the unknown?
  • How were you able to distinguish between the different markers? Why?

Conclusion:
How are the markers similar to fingerprints?

Materials:
Element gas tubes
Power source for gas tubes
Diffracting gratings
Colored or map markers

Activity #2 Element identification:

  1. Look at a light source through the diffraction grating.If you see vertical colors on the right and left you are ready. If you see colors at the top and bottom. rotate the grating 90 degrees.
  2. The teacher will set up the first gas tube for the class to practice with.
  3. Go to one of the gas tubes and look at the light through the diffraction grating.You will see vertical colors on each side of the diffraction grating. Draw only one of them on a sheet of paper and mark it as practice.
  4. The teacher will now set up a series of elements that you will draw the color spectrum on a sheet of paper for each element.Draw each spectrum as carefully as possible,since this will be the fingerprint you will use to identify the unknown.
  5. Once you have viewed all the elements, the teacher is going to give you one of the elements again.You will use your spectrum drawings to identify the unknown.
  6. When you have drawn the unknown, compare it with your drawings and write down on your sheet the name of the element you think is the unknown.

Questions:

  • What was the most difficult part of identifying the unknown?
  • How do you think scientists identify elements when there are several mixed together?
  • What are some jobs that might need to identify elements?

Extension:

look online or call an observatory about light spectrums and the universe