LESSONS: Chemistry

The majority of lesson ideas below require minimal resources other than the smartphone, and are relevant to introductory physics in high school and college. However, creative individuals are using smartphone science in more complex ways, with drones, engineering kits, and much more. Follow us on Twitter @PhysicsToolbox and see our Publications page for additional content.
Solute Concentration and Color Intensity

What is the relationship between solute concentration and color?

Try This

Using the Color Detector tool, measure the HEX values of various known concentrations of copper sulfate in an aqueous solution. Convert the HEX values to HSV (Hue, Saturation, Value) using an online converter. Plot mass of dissolved copper sulfate versus hue, and develop a mathematical model to describe the relationship.

 

Challenge Yourself

  • Determine the concentration of an unknown amount of copper sulfate based upon its hue value.

  • Determine what will happen to the relationship after the saturation point has been reached.

 

Related Resources

Beer's Law

What is the relationship between SOLUTE CONCENTRATION and LIGHT ABSORPTION?

Try This

Using the Light Meter tool, measure the light intensity as it passes through various cuvettes filled with different known concentrations of colored soda (or other solute). Plot absorbance (as measured by log (I0/I), the log of the intensity of light as observed through a control cuvette filled with water divided by the intensity of light observed through a cuvette filled with the solution) versus concentration.

 

Challenge Yourself

  • Determine the mathematical relationship between absorbance and concentration.

  • What is the meaning of the slope and y-intercept of the linear relationship observed?

 

Related Resources

Image Credit: Glen Gilchrist

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