In 1986, under Prime Minister Rajiv Gandhi, the Indian government declared February 28 as National Science Day to commemorate the groundbreaking discovery of CV Raman, the Raman effect. On this day in 1928, he formally shared his discoveries with the scientific community, marking an important milestone in physics.
His discoveries helped scientists understand how light behaves when it passes through different materials. National Science Day is celebrated every year to commemorate this achievement and encourage interest in science and technology.
Physicist Sir CV Raman won the Nobel Prize in 1930 for making this important discovery.
Raman used direct experiments and found that as light passes through the liquid, a small portion of the scattered light changes color.
Scientists quickly viewed the discovery as a major breakthrough, resulting in more than 700 research papers in just seven years.
What is the Raman effect and why is it important? More importantly, who is the smart man behind this pioneering discovery?
Raman’s Journey: Scientists and Scholars
Raman was born in 1888 in Terridge (now known as Tiruchirapalli), who was president of Madras, and became a family of Sanskrit scholars.
When he was 16, he received a bachelor’s degree from the Presidential College of Madras and ranked first in his class.
He was only 18 years old when he was in his master’s degree and published a research paper in the Journal of Philosophy. This is the first research paper from the Presidential Academy.
Due to his poor health, he was unable to study abroad. So in 1907 he married and moved to Kolkata, where he worked as an assistant accountant.
Even while working full-time as a civil servant, Raman spent his free time in the Indian Association for Science Training (IACS).
Raman helped make IACS more famous by conducting some award-winning research and engaging public demonstrations.
At the age of 29, he left civil servant job and became a professor at the Presidential College of Kolkata.
By 1921, CV Raman was known as an outstanding scientist in India and abroad.
That year, he traveled to England for the first time. On his way back he made an observation that would change his life and the world of science forever.
Raman was surprised by its dark blue color as he crossed the Mediterranean.
Having been dissatisfied with the color of the ocean only a reflection of the sky, he became more curious and decided to explore further.
Raman soon discovered that, as many believe, the blue of the ocean is not only a reflection of the sky. Instead, he found that the sun was scattered by tiny particles in the water (water molecules). This scattering causes blue light to spread more than other colors, making our eyes appear blue.
Water is composed of small particles called water molecules, each of which consists of two hydrogen atoms and one oxygen atom (H₂O). These molecules bind together to form liquid, solid or gaseous water.
Raman and his team in Kolkata are curious about how light travels. Their hard work led to an important discovery, now known as the Raman effect.
Raman effect
When light passes through the liquid, the Raman effect occurs and some scattered light changes color. This happens because light interacts with molecules in the liquid, thus changing its energy and wavelength. In short, when light hits a molecule, its wavelength shifts slightly, resulting in this color change.
When light encounters an object, it can bounce back (reflect), bend (refractive) or pass (transmit).
Scientists study how light scattering can change its energy by checking whether the particles it hits. This means that when light interacts with particles, it may produce or lose some energy, which may slightly change its wavelength or color.
Here is a simple way to understand it:
– Light is made of tiny energy packs called photons.
– When a photon interacts with a molecule, it may gain or lose some energy.
– Changes in energy affect the wavelength of the photon:
– More energy → Shorter wavelengths (move to blue light).
– Less energy → longer wavelengths (move towards red light).
– However, new photons are not created or destroyed in the process – the same photon is just a change in energy.
As shown by the Raman effect, this is the slight change in color when light interacts with particles.
Explain light scattering and material analysis
After studying 60 different liquids, CV Raman and KS Krishnan were titled “A New Type of Secondary Radiation” in their first report to nature. They found that in each case a small portion of the scattered light had a different color than the original light. Raman stressed that this is a common phenomenon and needs recognition.
Raman then confirmed these findings using a spectrometer and recorded the exact measurements. He published these detailed results in the Indian Journal of Physics on March 31, 1928.
Spectroscopy is a scientific instrument that dispers light into its different colors (spectrum) to analyze materials based on how it absorbs or emits light. It helps identify elements and study light properties.
Resume Raman’s discovery had a huge impact on the global scale, beyond his original intention. In his 1930 Nobel Prize speech, he explained that studying scattered light helps us understand the basic structure of the materials it passes through.
During this period, scientists focused deeply on quantum theory, which explained the behavior of tiny particles. Raman’s discovery is important because it helps scientists understand that light interacts with different materials at a very basic level. His work provides new insights into the nature of light and matter, and has had a significant impact on physics.
Light and matter: Science link
Light is a form of energy that can travel through waves and enables us to see things. It includes visible light, as well as invisible forms such as X-rays and infrared.
Matter is anything that has weight and takes up space, such as air, water, rocks, and even our bodies. It consists of tiny particles called atoms.
When light interacts with matter, it can absorb, reflect or scatter, and sometimes changes color or direction. This interaction can help scientists learn more about the materials and their properties.
Research materials with Raman spectroscopy safety
Raman’s discovery was very useful in chemistry, thus developing a new technique called Raman spectroscopy. This method can help scientists study different substances without damaging them. It is used to analyze natural (organic) and artificial (inorganic) materials, making it a powerful tool for identifying and understanding chemicals.
As lasers develop, more powerful and more concentrated beams can be generated, and Raman spectroscopy becomes more useful. Over time, its application has expanded greatly, making it an important tool in many scientific fields.
Today, Raman spectroscopy is used in many different ways. It helps experts study artworks and historical objects without damaging them. It is also used at airports and border checkpoints to detect hidden drugs in luggage.
(Girish Linganna is a defense and aerospace analyst based in Bangalore. He is also the Director of Add Engineering Components, India, India, Pvt. Ltd, Add Engineering GmbH, Germany. The views expressed in this article are only the author’s views)
