Ask an Expert

Saarthak, from class 8, asked us, “What is the use of linear equations in day to day life?”

Many of us feel that the study of algebra is unnecessary for daily life. However, this is only because people don’t understand how it makes our lives easier.

Here are a few uses of linear equations:
Example:
How would one determine the number of hours for any given number of days?
If x = no. of days and y = no. of hours, y = 24x is the linear equation which describes the relationship between the number of days and the number of hours.

A mobile company charges for any call as per the following scheme.
Rs. 1 at the start of the call, and Rs. 0.50 for any subsequent call.
Can you guess, what will be the relationship between the duaration of call (min) and the charge for the call made?
If x = duration of a call in minutes and y = charge of a call (in Rs.) , it is given by y = 0.50x + 1.

Equations are the best way to describe a relationship between various quantities. More than linear equations, other equations like quadratic, cubic etc have more real life applications. However, competency with linear equations will help you to deal with these equations better.

Since equations help in representing relationships between quantities (variables) in the compact form, they are widely used in Physical Sciences, Computer Sciences etc.

So we hope that, now, you will pursue equations more seriously. You can now look up more applications of algebra and then, tell people how it’s used EVERY single day to make our lives easier!

Tags: algebra, daily life, linear equations, math

Pulastya Gangopadhyay asked, “WHY IS CARBON DIOXIDE BAD FOR OUR LUNGS AND BODY?”

 
You probably know that oxygen is taken in and carbon-dioxide is given out from our body during respiration. Oxygen is collected from the inhaled air in the lungs and sent to different places in the body by the blood. Carbon dioxide is then collected from different parts by the blood and brought back to our lungs, from where it is then exhaled.

Carbon dioxide reduces the blood’s capacity to carry oxygen. Our body produces carbon dioxide continuously during respiration, hence, this carbon dioxide needs to be given out so that enough oxygen can be transported in our body.
If different parts of our body do not receive enough oxygen, our body will not be able to function properly.

Carbon dioxide does not contain any germs. And we do breathe in carbon dioxide also along with the air.

The smoke of a bus contains many toxic gases which can make you feel breathless. It also contains a gas called carbon monoxide which is very harmful. Carbon monoxide reduces the oxygen carrying capacity of blood MUCH more than carbon dioxide.

You can read more about this at the following web pages:
http://www.madsci.org/posts/archives/2005-06/1118758011.Gb.r.html

Tags: bad, body, carbon dioxide, harmful, lungs, oxgygen, respiration

Prabal asked, ” WHO INVENTED ELECTRICITY?”

First of all, you should know that nobody INVENTED electricity. It was already present in nature. Although Benjamin Franklin is commonly known as the ‘Father of Electricity’, a long list of people helped in DISCOVERING it and devising methods and instruments to use it.

The word “electricity” comes from the Greek word ‘elektron’. And do you know what this word meant? It was the Greek word for “amber”! You see, as far back as 600 B.C. the Greeks knew that when amber was rubbed, it became capable of attracting to it light bits of cork or paper. This was because of what we know now as electro-static attraction. (Amber is fossil tree resin, which is appreciated for its color and beauty.)

In the year 1600, English physician William Gilbert conned the term electric, from the Greek elektron, to identify the force that certain substances exert when rubbed against each other.

I’m sure you’ve seen the effects of static electricity yourself. In the winters - if the climate is dry in the region where you live, try rubbing a dry comb or a plastic ruler against your dry hair and then hold it away from your hair.

Now, let’s move on and see when major discoveries and inventions related to electricity were made.

in 1672, Otto van Guericke produced a more powerful charge of electricity by holding his hand against a ball of spinning sulphur.

In 1729, Stephen Gray found that some substances, such as metals, carried electricity from one location to another. These came to be called “conductors.

In 1733 a Frenchman called du Fay discovered positive and negative charges of electricity, although he thought these were two different kinds of electricity.

In 1745 Pieter van Musschenbroek invented the Leyden jar which acted as a capacitor.

Finally, in 1752, Franklin is said to have performed the famous experiment of flying a kite during a thunderstorm, (using a Leyden jar) which led to the discovery that lightning and electricity were somehow related. Benjamin Franklin did a lot of work to try and explain ‘what’ electricity was.

You can read more about the history of electricity at the following links:
http://www.wisegeek.com/who-discovered-electricity.htm
http://www.electricityforum.com/who-discovered-electricity.html

Tags: benjamin franklin, discovered, electricity, invented, leyden jar

Anwesh Bhattacharya asked, “WHY DOES THE MOLTEN MAGMA INSIDE THE EARTH NOT COME OUT COMPLETELY DURING A VOLCANO?”

First let’s try and understand what happens when a volcano erupts.

The erupting force of magma comes from internal gas pressure.

The material that forms magma contains a lot of dissolved gases — gases that have been suspended in the magma solution. The gases are kept in this dissolved state as long as the confining pressure of the surrounding rock is greater than the vapor pressure of the gas. When this balance shifts and vapor pressure becomes greater than the confining pressure, the dissolved gas is allowed to expand, and forms small gas bubbles, called vesicles, in the magma.

Now imagine these small gas bubbles building up in the magma - they will rise up in the liquid similar to a bottle of soda that has been shaken and opened.

As these gases try and escape, they cause the magma to flow out under pressure as well, which is what causes the eruption.

Now, all the magma does not come out, because it would take enormous pressure to push all the molten magma out of the core of the Earth. The mass of this magma is very large and the pressure with which the formed vesicles try and escape is not enough to push the ENTIRE mass of magma out.
We hope this has answered your question.

You can also visit the following websites to learn more:
http://encarta.msn.com/encyclopedia_761595520/magma.html
http://science.howstuffworks.com/volcano.htm

Tags: erupt, magma, volcano

Laila asked, “WHY FINGER NAILS GROW FASTER THAN TOE NAILS?”

Our finger nails grow at the rate of about 0.1 inch per month, which is twice as fast than the growth of toe nails.

And, to explain this unequal rate of growth, there are various theories that are advanced and a few of them, as explained below, seem to be quite common.

One theory suggests that hands benefits from better blood circulation - and thus, a better supply of oxygen and nutrients - because they are physically close to our heart than our feet.

Another theory is based on ‘trauma’ which means a physical injury caused by hurt/accident etc. The persistent minor traumas, such as typing (for which we use our fingers), actually stimulate the growth of the fingernails. Whereas our toes enjoys a virtually trauma-free existence inside socks and shoes.

This theory is from the perspective of evolution and genetics - nails are basically protective, and since our fingers are busier than our toes, maybe they’re more likely to get smashed and need replacing; hence the finger nails are by design made to grow faster.

There is another speculative theory that says that fingernails’ constant exposure to sun and air may aid their growth. But, feet are locked up in damp, dark shoes most of the time, a more encouraging environment for cultivating fungus and smells instead of nails.

And, that’s not all!

A pregnant women’s nails grow faster than normal.
Men’s nails grow faster than women’s.
The nails on our dominant hand grow faster.
And the middle finger of our dominant hand is the speediest of all. Enough??

Basically Laila, to explain any phenomenon there are various theories that are put forward and more often than not, the real explanation would be a combination of some or all of them. And, of course there would sometimes be a few exceptions too!

But it is always fun to look at a phenomenon from different perspectives, don’t you think?