Why Does Heat Smell?

At first, the title might sound pretty weird. But, this is something which most of us have experienced. While roaming outside on a hot day, we usually observe that the heat around us gives off a very peculiar (and not very pleasant) smell. Why do we get this smell? Is it actually the smell of heat? Let’s explore!

First, let us acquaint ourselves with the basics. Heat is a form of energy that gives us the sensation of temperature. If something has a significant amount of heat, we say it is hot, and when something is devoid of heat, we say it is cold. Heat, like most forms of energy, can travel from one material to another through various methods.

Firstly, I would like to tell you that as far as my research is concerned, I have found no reasons for this on any website. So, everything henceforth will purely be my logic. So, please note that it may be incorrect at some places.

Let’s start off with a question: What exactly does heat smell like? Well, as a matter of fact, burning plastic could be the closest match. It isn’t that pleasant and makes you feel worse, as if the sweltering heat wasn’t enough.

Let us now try to reason out as to why heat smells. We know that the air around us contains millions of particles, ranging from oxygen to dust. Now, when air absorbs heat, it tends to move faster (It is the tendency of particles to get excited when energy is provided). Due to this increase in energy, the molecules of air spread out at a rapid pace and accumulate any particulate matter around them.

Next, we know that heat is capable of burning things (I know this is obvious but hear me out). So, the amount of heat the air molecules would be holding might be sufficient to burn the particles suspended in it, as both the size and mass of the particles is very small. The smell given off by heat might as well be that of burning particles within it.

This also happens in heaters which haven’t been used for a long time. Due to accumulation of dust and soot, turning on the heat burns the particles and the heater gives off a very bad odour. So, remember to clean your heaters.

So, how was it? Did it get you all heated up? Feel free to comment in the Comments section.

Stay Safe, Stay Home!

Author: Venkata Bhamidipati

Why Do Batteries Lose Charge Over Time?

Batteries are a group of two or more cells packed together. They are used in many devices, from TV remotes to radio-controlled cars. They serve as a long time source of power and can be used for a decent timespan. However, we generally see that if we leave a battery outside after charging, it kind of loses its charge and makes us question ourselves as to whether we had charged it or not. So, why does this happen?

First, we need to know the structure of a battery, which is found below:

Source of Picture: http://www.baj.or.jp/e/knowledge/image/structure03b.gif

Not going into too much details about the structure, we shall see some important parts which will be relevant to our question.

First, the terminals. A battery has two terminals, a positive one and a negative one. The positive one has a small button-like structure on it called the metal cap and the negative terminal has a flat structure called the metal plate. These terminals are connected in the correct fashion to make conduction of electricity possible.

Next we have many layers of metal which enclose the inner parts of the battery, which is covered by a foil label, which is made of plastic and usually carries the name and company of the battery.

Now, inside the battery, there is a structure called the electrode. This electrode has a liquid inside it which is called an electrolyte (An electrolyte is a liquid which can conduct electricity). This is where the process starts.

When we pass current through a battery, the electrolyte present in the electrode decomposes (breaks down) and is converted into charged particles called ions. These ions help in creating a potential difference within the battery and help in conduction of electricity. (If you don’t know what potential difference is, check out the note at the end of this article of mine- https://pcbpedia.home.blog/2020/05/08/why-does-a-bulb-immediately-light-up-when-switched-on/

Eventually the batteries do run out of charge as the chemicals in the battery that make up the electrolyte also run out (Rechargable batteries are an exception as they can be used multiple times. This is because the reaction that takes place in such a battery are reversible i.e. the process can be repeated multiple times. The electrolyte is converted to ions and back to the electrolyte in such batteries)

Now, sometimes we observe that after we fully charge a battery and leave it in the open, it loses its charge, which becomes evident after it proves to be useless when you put it your kid’s remote controlled car and it doesn’t work, much to the frustration of the child!!! Jokes apart, we shall now see a phenomenon called “self discharge”.

No second meaning. Self discharge means to discharge one self, and in this case, a battery. This happens due to the surroundings in which a battery is kept. If you keep it out in the Sun, the heat will cause the electrolyte to decompose and lose its charge without even being connected anywhere. That is why it is advised to keep a charged battery in a cool place to increase its shelf life.

So, how was it? Did your electrolyte pump you up? Feel free to comment in the Comments section down below.

EXTRAS- Just For Fun:

Student: Which is the only mammal that can fly?

Teacher: Bats.

Student: Where do they get the energy from to fly?

Teacher: The food they eat.

Student: No. They get energy from “bat-teries”!!

Stay Home, Stay Safe!

Author: Venkata Bhamidipati

Why Does A Bulb Immediately Light Up When Switched On?

Source Of Picture: https://www.tdworld.com/smart-utility/article/20973412/whither-the-fate-of-the-incandescent-light-bulb

This article is credited to…Thomas Alva Edison (It is kinda obvious, right?) for his marvelous discovery.

So, we all know the importance of light in our daily life. It is the form of energy that enables us to see the things around us. A light bulb is a device that can produce light. But, how can it produce light so fast, that it lights up instantly after we turn its switch on? Let’s explore.

First, let us study the mechanism of a bulb with the help of the below diagram.

Electricity enters through the bottom of the bulb (the place labelled as Electrical Contact, where the bulb is connected to the source of voltage) and proceeds into the contact wires into the filament, which is made of a metal called Tungsten. The melting point of tungsten is very high (around 3,422 °C) and that is why it doesn’t melt even after prolonged passing of current. The tungsten filament is supported by the support wires. The whole structure is encased within a glass covering, which is filled with an inert gas (gases which don’t react with the surroundings, under normal circumstances), usually argon. Electricity should continuously pass through the contact wires to keep the bulb glowing.

Now, the question of interest today. How does the light bulb immediately start to glow when we switch it on? It is evident that current does not move at infinite speed (Maybe I exaggerated that too much!). So, how does this happen?

This observation is the result of a phenomenon called ‘electron drift’. If you didn’t know, electrons are tiny particles, which are found around an atom. Most of us know that electrons are the primary cause of the flow of current, usually termed as electricity. So, how do they move so fast? Allow me to explain.

I have already told you that the filament of a bulb is a metal called tungsten. Now, metals contain atoms and atoms contain electrons. This constitution is seen in matter everywhere. However, metals are different. Some metals have electrons which are free i.e. they are not a part of any atom and are not bonded anywhere. These electrons are simply called ‘free electrons’. Now, when we switch on the switch of a light bulb, it creates a potential difference (a potential difference refers to two points, where the energy at one point is greater than that at another point. In such cases, energy moves from the region of higher concentration to lower concentration). If you still didn’t get the meaning of potential difference, scroll to the bottom where I have given an explanation with the aid of an example.

Due to the potential difference, an electric field is created. As a result of the field, the free electrons in the filament acquire a velocity (speed) known as the ‘drift velocity’ (The velocity acquired by a particle when in an electric field). Due to this, the electrons start to move and produce electricity. This heats the bulb and it glows.

So, we see that the electricity doesn’t come from the power source. It comes from the free electrons which are present in the filament. Now, another question arises. Whenever we switch off a bulb, why does it remain lit for some time. Let’s explore.

It is quite a logical question. When the light bulb is lit, it has electricity flowing within it. So, heat is produced. Now, when you switch off a bulb, the heat doesn’t magically vanish in a second. So, during the time taken for the bulb’s heat to dissipate out, the bulb shines faintly.

So, how was it? Did it light up your bulb? Feel free to comment in the Comments section down below.

Note: Potential Difference- Consider a tank on a hill and a pond in a valley. You have a pipe and you have to use it to transport the water from the tank to the pond. Now, making the pipe stand length wise into the tank won’t do anything. Ideally, you should keep the pipe at an inclined position so the the water flows down. This is exactly what potential difference (also called voltage) is (except that we don’t use water). The most common device used to create a potential difference is a battery.

Author: Venkata Bhamidipati

Why Does Catching A Fast Moving Object Cause Pain?

When was the last time you played cricket? And got hurt badly after you tried to catch a fast moving leather ball (Ouch!)? Well, some might have wondered about why it pains and how to avoid it. Let’s see.

First, we should be acquainted with the term “Impulse”. In terms of Physics, impulse is defined as “the force (say F) which is applied for a certain time interval (say T).” Mathematically, it can be written as follows:

Impulse (I) = Force (F) x Time (T)

An impulse creates a change in the speed of a body. To make it more simple, let us consider a situation.

Consider a ball placed in front of you. Obviously, it wouldn’t start moving by itself (unless you know witchcraft). Now, if you push the ball, it will move. Continue pushing it and it’s speed will increase. Voila! You just created an impulse.

Now, if we rearrange the above equation, we get:

Force = Impulse/Time

Now, we see that force is inversely proportional to time. In simpler words, we can say that if the time of contact is increased, the force is decreased and vice versa.

Now, to the main topic. Applying the same concept, it is easy to see that if we grab a fast moving ball all of a sudden, the time interval the ball takes to stop is very small, which inturn increases the force and makes us regret we did that!

How to avoid it? Well, to minimise the force, we need to increase the time interval as much as possible. So, cricketers usually swing their hand back after catching a flying ball. This increases the time interval and reduces the force on their hand.

So, how was it? Did it make you get up and go play cricket? Feel free to like the post and comment in the Comments section below. I shall be open to your ideas for my future posts.

Author: Venkata Bhamidipati

Can Mass Be Negative?

Mass is defined as the amount of matter in a substance. What we measure on a weighing scale is our mass. But, can we have negative mass?

Before I dive deeper into this topic, let me explain why mass theoretically can’t be negative. This is because mass is a scalar quantity.

A scalar quantity is a quantity which has only magnitude and no direction. For example, temperature, time, area, density etc. Imagine someone saying, ” The temperature is 38°C North today!” It wouldn’t really make sense! So, scalars don’t have direction and are either positive or zero.

On the other hand, vector quantities like force, momentum, pressure etc. have both magnitude and direction. They can be positive, negative and zero.

So, you might have concluded that mass cannot be negative. But that is not true. Proving the impossible is what science does and it has done just that. Presenting- Negative mass!!

Negative mass has properties exactly opposite to that of positive mass. For example, when it is pushed in one direction, it moves in the other! So, what would happen if we used negative mass in building stuff? (Disclaimer: From here, my thoughts have been presented.)

It would probably float in the air!! We can’t really tell what will happen because negative mass is still something very weird. Imagine this scenario: A friend of yours has a mass of 50kg. If you (somehow) remove the 50kg mass from him, he would be mass-less (It is a different thing that he would cease to exist!!)! Now, if you remove something more from ‘him’, he would have negative mass. But, how can you remove something from him when there is nothing left?! Tricky questions right?

Scientist have managed to create negative mass in the form of a black fluid with the help of Rubidium (Rb) atoms. So, the concept is not entirely wacky!!

So, how was it? Did it make you rush to the weighing scale to check your mass? Feel free to comment in the Comments section.

Author: Venkata Bhamidipati

Why Do Substances Sublime?

Almost everyone of us must have experienced the phenomenon of sublimation, be it the disappearing case of naphthalene balls without a trace or the magical effects of dry ice in a theatrical performance. Sublimation is defined as the conversion of a substance from its solid state to its gaseous state without passing through the liquid phase. But, why do substances sublime?

Before I answer this, let me give you a brief background. To convert any substance from one state to another, two factors play a pivotal role: temperature and pressure. If temperature is increased, state change happens from solid to liquid to gas but if pressure is increased, state change happens from gas to liquid to solid.

For this discussion, let us consider dry ice (solid CO₂ ). Carbon dioxide exists in its solid state at -78.5°C, which is way below that of water (0°C). At STP (Standard Temperature and Pressure), carbon dioxide exists as a gas.

I would like to clear one thing here- Liquid CO₂ DOES exist. The only factor that makes it impossible to naturally obtain liquid CO₂ is pressure. CO₂ exists as a liquid at a pressure condition of 5.1 atm (atmospheric pressure) and temperature between –56.6 and +31.1°C. Though the temperature can be naturally obtained on Earth, the pressure of 5.1 atm is impossible to obtain naturally. The Earth’s atmospheric pressure is 1 atm. So, to obtain liquid carbon dioxide, we need to quintuple the atmospheric pressure! That wouldn’t be the best thing to do as it would affect all organisms adversely.

Similarly, any sublimable substance (ammonium chloride, naphthalene, camphor, iodine) would not be able to exist in liquid form due to unfavourable pressure conditions (naturally, that is).

So, how was it? Feel free to comment in the Comments section.

Author: Venkata Bhamidipati

Source Of Picture: Wikipedia

Why Black Absorbs Light And White Reflects Light?

How many of you have wondered why black absorbs light and white reflects light? Actually, that isn’t how it works.

Black doesn’t absorb light. In reality, what absorbs all the wavelengths of light (abbreviated as VIBGYOR) appears black (I suppose you got what I meant). Also, black is not a colour. Black is the absence of colour.

Similarly, white doesn’t reflect light. What reflects light is white in colour and the reflection of all wavelengths of light makes an object appear white.

Consider this fact. If you take a black object and subject it to a certain wavelength of light except visible light, it would appear white! So, an important conclusion here is that an object appears black only if it absorbs “visible light” [light between the wavelengths 4 x 10 ^-7 m (violet) to 7 x 10^-7 (red)] and appears white if it reflects visible light.

Now, we come to the other topic of discussion- How can something absorb or reflect light? Whenever light falls on any object, the object only absorbs the light if it possesses energy equal to the difference of the energies in two successive shells of an atom (ΔE). If it is more or less, the light will either be reflected or transmitted through the object.

In absorption, the light energy is converted to heat energy (That is why a black object heats up when exposed to light) and in reflection, light is bounced back from the object when the atoms in it vibrate.

However, there is one more case. Light can be transmitted through the substance.The atoms absorb the light energy for a very short duration of time and then release it to the neighbouring atom. I have already talked about this in my article “How Light Passes Through Glass?”.

So, how was it? Feel free to comment in the Comments section.

Author: Venkata Bhamidipati

Source Of Picture: https://www.photovideoedu.com/Learn/Articles/the-color-of-light.aspx

If Torches Emit Light, Can Something Emit ‘Dark’?

(Please note that this article is not based on proved facts. It is just a theory.)

Whenever the power goes off, we rush to get a torch, which immediately fills light in the midst of darkness. But, what if there was a device that could produce ‘dark’ in the midst of light? Creepy, huh?

Almost everyone must of heard of anti-matter – matter that is made up up anti-subatomic particles. Anti-matter consists of anti-protons (which carry a negative charge), anti-electrons (also called positrons – carry a positive charge), and anti-neutrons (which carry no charge). If someone were to combine antimatter and matter, a very large amount of energy would be released.

Now, if light contains photons, can’t “anti-light” (or ‘dark’) contain anti-photons? Though highly possible theoretically, it doesn’t seem very practical. We know that photons emit energy. So, “anti-photons” should emit “anti-energy”. This is definitely a weird topic to grasp and that is why is it just a theory. But, just in case we do shine a ‘dark’ (I suppose you get what I meant), what would we see?

In simple terms, nothing! Wherever we shine the ‘dark’, we would just see a black spot. That black spot is actually a black hole (Black holes are the remnants of massive stars which form in the Universe. The gravitational strength of a black hole is so strong that not even light can escape. So, they are basically invisible to our eyes) because it is a place where no light exists! So, creating a black hole on Earth wouldn’t be the best thing to do.

So, in conclusion, if we somehow do manage to create a device that can emit ‘dark’, we must be ensure that it does not turn out to be a black hole. It should have particle and wave nature just like light and should have the physical properties of light.

So, how was it? Did it make your head spin and make you forget the difference between light and dark? Feel free to voice out your thoughts in the Comments section.

Author: Venkata Bhamidipati

How Light Passes Through Glass?

Light passes through glass because glass is transparent. And why is glass transparent? Because light passes through it. This is the same old answer we get when we ask such a question. Let me tell you how this works:

We see objects because light falls on it. This is in the case of solids. In glass, which is a different state of matter on its own (a supercooled liquid, to be precise), the atoms are arranged in structures called lattices. When a ray of light falls on glass, the photon (the smallest particle of light) interacts with the electron in the atom of the lattice. As photon is a form of energy, the electron absorbs it and moves on to the next shell (imaginary paths in an atom). but, as electrons can’t stay in another shell for a long time, it re-emits the energy absorbed and the energy (basically the photon) moves on to the next atom, until it exits the glass medium.

Some might wonder as light passes through glass, shouldn’t it refract (bend)? Actually, it does. But, as our eyes can’t detect such phenomenon at a microscopic level, it seems to us that light passes in a straight line.

So, how was it? Did it “lighten” you up? Feel free to share your thoughts in the comments section.

Author: Venkata Bhamidipati