# Principles of Pressure

This link will guide you to an article with a photo of mine demonstrating  principles of pressure.

Here, the demonstration is about how increment of the area of the force being applied would reduce the pressure. Also, it clarifies the fact that it is not necessarily the force applied on a nail which makes it penetrates a surface, but the pressure being applied on the surface.

The theory behind this demonstration is explained in the following links:

1) An interesting explanation (good way to explain the effect to kids or elementary level students) VIDEO

2) More detailed explanation (effectively explains how the fact pressure = force/area works  on a person on a bed of nails) ARTICLE

3) Real explanation (with a small bed of nails on top and breaking a concrete block on the top bed with a sledge-hammer) VIDEO

4) More explanations (explanation of walking on broken glass,  dipping fingers in molten lead, bed of nails and breaking a concrete block, and picking up a piece of orange-hot space tile)  ARTICLE

# Invisible, Transparent, and Invisibility!

These three words came into my in depth consideration when I was getting prepared to do a presentation on “Invisibility Cloak: Controlling Electromagnetic Waves”.

I would consider these three terms in the context of cloaks:

1. Invisible cloak: A cloak which is there but you cannot see it. It does not imply that it makes the person who wears it going to be invisible. Only the cloak will be invisible.

2. Transparent cloak: A cloak which would make light pass through it. Unlike in the case of “Invisible cloak”, a “Transparent cloak” can be visible to a naked eye. Yes, it would enable the viewer to see the object being covered. One example would be a rain coat made out of a transparent/see-through polythene.

3. Invisibility cloak: A cloak which would make both the object being covered and the cloak invisible to some one viewing from outside. That is, when an object(s) is/are covered by this kind of a cloak the viewer should not see the cloak or the object(s) being covered. He/She should see nothing at the place where the cloak and the object(s) are. In terms of Physics, this would have to direct all the incoming light rays in the same direction it was propagating. For example, if a light ray was coming from North to South with a 10 degrees of angle towards West and hits the cloak from behind (of the person who is wearing it) it should appear from the front in the same direction and it should be in the same line as it would propagate without the cloak. Also, no light rays from the object(s) being covered by the cloak should come out through the cloak.

It is questionable whether we can call it  an “Invisibility cloak” simply because it makes the object being covered invisible to our naked eye. If it is a complete “Invisibility Cloak” it should have the same physical behavior of ray optics (explained above) across the full electromagnetic spectrum. Otherwise, for example, in military applications a night vision glass or a similar device could recognize that there is an object being hidden.

Considering the fact that objects radiates unless it is at absolute zero temperature, it is still debatable whether a complete “Invisibility Cloak” is possible.

# Computing a Theory of Everything

Computing a Theory of Everything
A TED talk by Dr. Stephen Wolfram.
Long Beach, California: February 2010.

The title says what the talk is about. So, I am not going to explain everything here.

Dr. Wolfram present a broad idea here, which is even not clear for him. But, he himself believes it is possible. He shows the things they have done so far to convince that we can have some faith on “Computing a Theory of Everything”.

In Dr. Wolfram’s words: “So, will we find the whole of physics? I don’t know for sure, but I think at this point it’s sort of almost embarrassing not to at least try.”

Yes, there is nothing like trying!

# Solar Panel design – it is not all about energy – it will be a fashion or a passion in the future

This link will guide you to an article written by Patricia Daukantas.

Pay your attention toward the energy it generates per year: 2,500 kWh

This is the energy needed for a 285 W device to run 24X7X365.

This energy is generated while conserving the beauty! Isn’t it great!

In terms of money: If 1 kWh costs \$ 0.12, then the annual savings from the electricity bills would be \$ 300.

This leads me to think more about Solar Energy.

If you use a 2500 W solar panel system (which would cost you about \$ 6000 – for a Gird-Tied system with no battery and about \$ 10000 with battery storage), annual savings would be around \$ 1,200.  It will take up to 5 to 8 years to cover up the cost. But, for a system with batteries, you will have to replace the batteries after 8 years. Which means, it won’t be a profitable investment (in terms of finance) even after 8 years for a system equipped with battery storage.

There are few challenges for us:

1. Increasing the efficiency of solar panels while keeping them easily mountable (if possible flexible and transparent), light weight, and cost-effective. We should decrease the price per Watt investment*.

2. Increase the efficiency of the batteries and their life span while the production cost of the batteries be lower.  Or else, we should be able to produce the batteries with the current efficiencies and life span for a very low-cost.

3. If we accomplish above two challenges we will be able to meet future energy needs. Can we call our selves “successful” by simply addressing the energy needs? What about the environment? What would be the side effects? Will the manufacturing process harm the environment? What would happen to the used batteries? What would happen to the damaged solar cells? Will they harm our environment? We should address the challenge of protecting the environment as well. Otherwise, we cannot be called “successful” even if we address the energy issue.

Fulfilling all the 3 challenges should be our challenge. Not just one of them.

Are we ready to take up the challenge?

Solar energy… it is our future energy source. It was our ancient energy source. Even though you do not realize… it is our current/present energy source as well!

Let’s create a better tomorrow!

– Jehan

* – investment or cost? – I always see it as an investment. An investment for a better future.

# Is Physics difficult?

Physics is understanding the nature… I always believed it.
Professor of Physics Emeritus Walter Lewin adds something strongly to it… without physics the technology wouldn’t have advanced this much.

Even though I cannot say exactly…
For me; Biology, Marketing, or Finance would have been harder than Physics.

We should admit, not everyone is good at Physics. But, not everyone is good at marketing either.

Professor Lewin calls bad teachers as “criminals”. In a way he is right. But, you cannot blame on all teachers and/or professors for not making you good at a subject. For example, if you are weak in Mathematics you may find Physics hard.

But, this video gives us something to think about…
for teaches/lecturers as well as for students and future teachers/lecturers.

Teaching is a responsible service (for me it is a more of a service than a job).
In a way it is a job that creates job makers.
In a way it is a service that leads the future.

A teacher should never regret that he/she could not become a doctor, engineer, businessman, or scientist. He/She has the ability to lead/create/inspire many!

Respect!