Intro to the Vernier Colorimeter Lab Vernier is

Intro to the Vernier Colorimeter Lab Vernier is the software data collection computer software Colorimeter is one of the data collection probes Probe and computer interface with each other

Models of Colorimeter New: Rounded Old: rectangular Both serve the same function: Measure the amount of light energy absorbed or Transmitted

The Nature of Sunlight • Light is a form of electromagnetic energy, also called electromagnetic radiation • Like other electromagnetic energy, light travels in rhythmic waves • Wavelength = distance between crests of waves • Wavelength determines the type of electromagnetic energy • Light also behaves as though it consists of discrete particles, called photons

LE 10 -6 10– 5 nm 10– 3 nm Gamma rays 103 nm 1 nm X-rays 106 nm Infrared UV 1 m (109 nm) Microwaves 103 m Radio waves Visible light 380 450 500 550 600 650 700 750 nm Shorter wavelength Longer wavelength Higher energy Lower energy

Pigments: Light Receptors • Pigments are substances that absorb visible light • Different pigments absorb different wavelengths • Wavelengths that are not absorbed are reflected or transmitted • Leaves appear green because chlorophyll reflects and transmits green light

Interaction of Light with a pigment

Vernier Software Screen: showing how it collects, stores and analyzes data Live read out window Green collect button

Determining the Unknown Concentration from the line of best fit: use the absorbance value; draw a horizontal from value on y axis to line of best fit; draw a perpendicular line from that point and read concentration. Unknown concentration Is 18%