Real-life Experiments of Light Absorption

Some of the real life experiments based of absorption of light is discussed below:

UV Light Absorption in Sunscreen Experiment

Aim: To compare the effectiveness of different sunscreens in blocking UV light using a UV light source.

Materials Needed:

• Different types of sunscreen (with varying SPF levels if possible)
• UV light source (such as a UV flashlight or lamp)
• UV detector or UV-sensitive paper
• Optional: Spectrophotometer for quantitative measurements

Procedure:

1. Apply a thin layer of each sunscreen on separate sections of the UV-sensitive paper.
2. Place the UV-sensitive paper under the UV light source.
3. Turn on the UV light source and expose the paper to UV light for a specified time (e.g., 1 minute).
4. Remove the paper from the UV light source and observe any color changes or darkening in the sunscreen-coated areas.
5. Measure the intensity of UV light transmitted through each sunscreen using a UV detector or spectrophotometer.

Explanation: This experiment shows how sunscreens absorb and block ultraviolet (UV) light which is harmful to the skin. The effectiveness of sunscreen can be observed by comparing the degree of darkening or color changes in the sunscreen-coated areas of the UV-sensitive paper after UV exposure. Higher SPF sunscreens or those designed to block specific UV wavelengths will show greater UV protection, highlighting the role of light absorption in sun protection.

Absorption Spectra of Plant Pigments Experiment

Aim: To extract and analyze the absorption spectra of plant pigments using chromatography and spectrophotometry.

Materials Needed:

• Fresh Plant leaves (spinach, beetroot, or other sources rich in pigments)
• Solvents (such as ethanol or acetone)
• Chromatography paper or thin-layer chromatography (TLC) plates
• Spectrophotometer or colorimeter
• UV light source (optimal for fluorescence measurements)

Procedure:

• Crush or grind the plant leaves to extract pigments using a suitable solvent (ethanol or acetone).
• Filter the pigment extract to obtain a clear solution.
• Apply the pigment extract onto chromatography paper or TLC plates and allow it to dry.
• Develop the chromatogram using a solvent system that separates the pigments based on their solubility and polarity.
• Use a spectrophotometer or colorimeter to measure the absorption spectra of the separated pigments at different wavelengths.
• Use a UV light source for fluorescence measurements of certain pigments like chlorophyll.

Explanation: This experiment explores the absorption spectra of plant pigments, such as chlorophyll, carotenoids, and anthocyanins. Chromatography separates the pigments based on their affinity to the solvent, while spectrophotometry measures the amount of light absorbed by each pigment at various wavelengths. The absorption spectra reveal the specific wavelengths of light that each pigment absorbs, contributing to their distinct colors and roles in photosynthesis.

Light absorption is the process by which light energy is absorbed by a material, causing it to gain energy is called Light absorption. This absorption can result in various outcomes, such as heating the material, triggering chemical reactions, or causing a change in the material’s properties, such as color. Real life applications of light absorption involves conversion of solar light to electrical energy, phototherapy, UV and IR Spectroscopy to analyze the properties of materials.

Light absorption refers to the process by which light energy is absorbed by a substance, leading to the excitation of its electrons to higher energy levels. When light is absorbed and then emitted by a material, the intensity of the light get reduced.