From UPSC perspective, the following things are important :
Prelims level : Whitest paint and its composition
Mains level : NA
Engineers in the US have created what they are calling the whitest paint yet.
What is the whitest paint?
- The researchers created an ultra-white paint pushing the limits of how white paint can be.
- This older formulation was made of calcium carbonate, while the new one is made up of barium sulphate, which makes it more white.
- The newer paint is whiter and keeps the surface areas it is painted on cooler than the formulation before this could.
- If this new paint was used to cover a roof area of 1,000 square feet, it may be able to get a cooling power of 10 kilowatts.
- Most ovens use up about 2.3 kilowatts to run for an hour and a 3 ton 12 Seasonal Energy Efficiency Ratio (SEER) air conditioner uses up about 3 kilowatts to run for an hour.
The researchers have claimed that this paint may be the closest equivalent to the blackest black paint called “Vantablack” which is able to absorb up to 99.9 per cent of visible light.
What determines if a colour absorbs or reflects light?
- To understand how this works one needs to note that whenever an object is seen by the eye, it is either because of sunlight or the artificial light in the room.
- This light is made up of seven different colours (Violet, Indigo, Blue, Green, Yellow, Orange and Red or VIBGYOR).
- Specifically, light is made up of wavelengths of different colours.
- If an individual is looking at a sofa that is green, this is because the fabric or material it is made up of is able to absorb all the colours except green.
- This means that the molecules of the fabric reflect the green coloured wavelengths, which is what the eye sees.
- Therefore, the colour of any object or thing is determined by the wavelength the molecules are not able to absorb.
Try this PYQ:
Q.Rainbow is produced when sunlight falls on drops of rain. Which of the following physical phenomena are responsible for this?
- Internal reflection
Select the correct answer using the codes given below:
a) 1 and 2 only
b) 2 and 3 only
c) 1 and 3 only
d) 1, 2 and 3
What determines which wavelength of light will be reflected and absorbed?
- This is dependent on how electrons are arranged in an atom (the building block of life, an atom is made up of electrons, protons and neutrons.
- These three particles make up everything in the known universe from mountains, planets, humans to pizza and cake).
- In contrast, if an object is black, it is because it has absorbed all the wavelengths and therefore no light is reflected from them.
- This is the reason that darker objects, as a result absorbing all wavelengths tend to heat up faster (during absorption the light energy is converted into heat energy).
So, what makes the paint so white?
There are two features:
- One is the paint’s high concentration of a chemical compound called barium sulfate, which is also used to make photo paper and cosmetics white.
- The second feature is that the team has used different sized particles of this chemical compound, which means different sizes scatter different amounts of light.
In this way, the varying size of particles of the compound makes sure that the paint can scatter more of the light spectrum from the sun.