Learning About Light: Spectrophotometers And Colorimeter

Spectrophotometers And Colorimeter

Have you ever tried to notice if light passes through a glass of water? Would the same amount of light pass through a glass full of milk or dye? The subtle science of light and reflections is what works here. To know much about the phenomenon of light, it is essential to understand light.

Light is nothing but electromagnetic radiation that can be seen by humans within an electromagnetic spectrum. Every ray of light has a wavelength, and every wavelength makes us see a different colour. So we see colour when we see visible light of different wavelengths. When all the wavelengths combine, it becomes white. 

Light or electromagnetic radiation often has wavelengths that make it impossible for humans to see. A human being can only see light having a wavelength of 400-700 nanometers. Electromagnetic radiation having wavelengths below or above this range cannot be seen by humans.

Light flows, carrying photons, which are also called light particles. A young student might wonder where the light comes from. Light comes primarily from the sun. Light also has artificial sources. One thing is clear: light makes us see things. If there is no light, humans won’t be able to see things. At the same time, light is full of interesting phenomena that are related to the universe and its origin. 

Spectrophotometer and spectrophotometry 

Spectrophotometry is a technique through which scientists can measure the intensity of light. The intensity of light refers to the power of light. The intensity of power is also concerned with the amount of light going through per unit area and per unit time. We find the intensity of light because the more intense it is, the brighter the flight is going to be. When light passes through a chemical compound, it either transmits or absorbs the light.


Spectrophotometry aims to measure the absorption of photons by the solution through which light is passing. In other words, this technique helps us to find how much light gets absorbed when passing through a chemical solution. Spectrophotometry is used in biochemistry, clinical labs, and molecular biology, etc. 

A spectrophotometer is a device that is used to apply the technique of spectrophotometry. A spectrophotometer can be divided into two parts depending on the materials it is made up of. These two parts are the spectrometer and the photometer. A spectrometer is used to produce or transmit a beam of light of different wavelengths. On the other hand, a photometer is used to detect the intensity of light or the number of photon particles that are being absorbed in the process. 


A spectrophotometer requires a light source to measure the intensity of light. When a beam of light passes through the monochromator, which is used to split the beam of light into different wavelengths. Often, prisms are used for this purpose. After light splits into different wavelengths, a wavelength selector picks out a specific wavelength to be passed through the sample. When a specific wavelength of light passes through the sample, the photometer detects its intensity.

The reading taken by the photometer is then shown on a display. A calorimeter works on the same principles as a spectrometer, but unlike a spectrophotometer, a colorimeter finds out the concentration of a solution. In other words, a colorimeter is designed to find out how much wavelength gets absorbed by the sample. So, a spectrophotometer and a colorimeter are two different instruments that have different but related uses. 


Types of spectrophotometer

Single beam – A spectrophotometer that uses only a beam of light to measure the intensity of light is called a single-beam spectrophotometer. Since there is a single beam of light passing through the solution, measurements of the intensity of light are taken before and after the light passes through the solution. 

A single-beam spectrophotometer is less costly as compared to its alternative. Also, since a single-beam spectrophotometer does not split light into different beams, it gives a better output. 

A single-beam spectrophotometer
A double beam spectrophotometer

A double beam spectrophotometer uses two beams of light to measure the intensity of light and is called a double beam spectrophotometer. In a double beam, spectrophotometer light is split into two beams, i.e., the sample beam and the reference beam. The sample beam aims to measure the absorption of light within the sample, whereas the reference beam measures the absorption without passing through the sample. A double beam spectrophotometer is more effective in detecting light and speedy operation of the activity. 


Spectrophotometer and colorimeter Project Work 

Did you ever think that the food colouring you use while making tasty dishes might be related to a spectrophotometer and a colorimeter? If not, then you should try some cool project work for these two instruments. Both of these instruments are used in a wide range of industries, such as biochemistry, molecular biology, agriculture, biomedical research, plastic and manufacturing industries, cosmetics, optics, etc.

With such wide application, a spectrophotometer and a colorimeter have become very important tools for scientists or future engineers who are curious about light and color. 

For budding scientists, project work could be a helping hand in understanding the mechanics of a spectrophotometer and a colorimeter. Projects are descriptive and practical assignments that help students improve their conceptual knowledge as well as their practical skills.

Through these cool projects, a student can get hands-on experience with these devices and be industry-ready. While you can manage to understand the science of spectrometry and colourimetry through theoretical understanding, you won’t be able to diagnose the issues related to them if you have never worked with these devices before. To eliminate the issues of practical experience, students must try DIY project ideas related to a spectrophotometer and a colorimeter.

Teachers and parents can provide such project work to students to ensure qualitative learning for children. Project work is the best way to boost the confidence of students, especially college-going students. There are several other benefits to project ideas as well, such as skill and personality development.

Project work infuses creativity in students, which helps them excel in their career field and brings innovation. Students can also work on their analytical skills and problem-solving skills with such projects. The project work also includes educational tools, making them suitable for inclusion in classroom learning. Therefore, teachers can use this project work in the classroom to ensure student engagement and maximum retention for students. 

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