Do Not Write On This Sheet—Write In Your Notebook

Coloring the Elements

Part I: Flame Tests

Introduction: Flame tests are a common method of determining unknown substances. Recently a skeptic food consumer (we’ll call him Pratticus) claimed that bananas do not contain significant amounts of Potassium (K). A renowned anonymous scientist (we’ll call him Prattical) refuted Pratticus’ claim and further claimed that bananas carry not only potassium, but other vital nutrients as well, including sodium (Na). The not-so-anonymous scientist Bill Nye said “extraordinary claims require extraordinary proof!”

Purpose: Your goal is to try and provide some proof of either claim.

Research: In class we have discussed how each element will give off a unique light wavelength when burned. To accomplish the goal, you will conduct a flame test to try and identify individual substances in a common item: bananas. Flame tests provide qualitative evidence of substances due to distinct flame colors and characteristics.

  1. Question: Are Potassium (K) and Sodium (Na) present in bananas?
  2. Hypothesis: Circle one!

Do Not Write On This Sheet—Write In Your Notebook

ü  If the flame colors of a banana match the K or Na samples, then the banana contains that element.

ü  If the flame colors of the K or Na are not observed when a banana burns, then the banana does not contain the element.

Do Not Write On This Sheet—Write In Your Notebook

Procedure: Rotate to the stations and follow the safety and lab procedures there.

  1. Station 1 Data: Record your observations in your science notebook.

Potassium Chloride
Sodium Chloride
  1. Station 2 Data: Record your observations in your science notebook.
  2. Analysis: Answer each question (using complete sentences) based on your group’s data. Record your responses in your notebook.
  3. What colors were observed with the banana chip flame test?
  4. Was it possible to distinguish any potassium from the sodium?
  5. What tools or equipment might make distinguishing the different colors easier?
  1. Conclusion: Write 2-3 sentences that address the introduction, answer the question, and support or refute the hypothesis.

ð  Does your data confirm either claim? What ‘proof’ do you have?

ð  Are potassium and sodium present in bananas?

ð  Was your hypothesis supported or refuted?

Part 2: Visible Light Wavelength and Frequency Lab- Data Sheet

Data Table:

Trial Run

/

Trial 1

/

Trial 2

/

Trial 3

/

Average

(Total¸3) / Frequency
(Average¸Time)

Tally

/

Total

/

Tally

/ Total / Tally / Total / Tally / Total

Red

Green
Violet
Time

Lab Questions:

1.  Look at the wavelengths and frequencies of the three waves. What patterns do you notice about the relationships between the three colors?

2.  Which color had the shortest wavelength?

3.  Which color had the longest wavelength?

4.  Which color had the highest frequency?

5.  Which color had the lowest frequency?

6.  What is the relationship of the red wavelength to the green wavelength?

7.  What is the relationship of the red wavelength to the violet wavelength?

8.  What is the relationship of the red frequency to the green frequency?

9.  What is the relationship of the red frequency to the violet frequency?

10.  If waves are moving at the same speed, what is the relationship between wavelength and frequency?

11.  Based on the above relationship, if you were to look at a blue wave, would it have a higher or lower frequency than the green wave?

12.  Based on the above relationship, if you were to look at an orange wave, would it have a longer or shorter wavelength than the green wave?

13.  If Velocity = Distance / Time, what was the velocity of the waves in this lab?