What is Temperature?

I was thinking about what is Temperature.


What it means for something to be in particular temperature? I looked around in the net, and learned that it is simply average kinetic energy of molecules.

If something is hot, the molecules in that something is moving around or oscillating faster. In the case of metals it is electrons. If something is cold, the molecules are relatively slow.

Why do we feel hot when we touch a hot object? The molecules in the object collide pretty hard on our fingers, trying to disturb our cells which is felt by our neurons as 'hot'.

Why do we feel cold? When molecules in the air is taking away average kinetic energy from us through collisions and we lose energy [heat].

What's the use of physics?

One word answer - Electricity.
Can you think of living in a world without electricity? What we take for granted came from physics.
Although that's not the reason for physics [its for its own sake] its the utility of it.
So today's Mars exploration etc. will turn into tomorrow's 'Electricity'.

Magical scientific facts

1. What we see is only part of the Electro magnetic spectrum.
2. Energy and mass is related through speed of light. What? what is speed have to do with mass or energy!
3. Time is not absolute. No simultaneity.
4. Gyroscope turning.
5. Brain seeing faces all over the place. Hollow mask.

10 most important scientific questions - part I

This is my list of 10 most important scientific questions.

1. What is consciousness? How does it "emerge"?
2. What is the fate of universe? If universe collapses in big crunch what will happen after that? Endless void? What does it even mean? BTW, what was "before" big bang? I know time started in big bang. But suddenly why some 14 Billion years ago, universe had to start? And it started out of what? I placed consciousness before this question as answer to 1) may have implications for this, although it is probably even deeper question.
3. Are there other intelligent creatures in the universe? [I am pretty sure there are organisms outside earth, at least single celled ones like bacteria]
4. How exactly quantum wave function collapse to an eigen value occurs upon observation? Is it a "real" feature or an artifact of our current incomplete quantum theory?
5. How to build physical theories based on discrete space-time? It is obvious, that real numbers are anything but real [talk about infinite precision!]. Time can only be measured through some periodic activity and there is definitely a limit to fine grained granularity we can go into. Since time and space are interchangeable it implies there should be a limit to space measurements as well. That said why is our calculus [continuity] based theories working at all?
6. Are there any near earth objects which has high probability of collision with earth and wipe out humanity, in say next 1000 years? On a related note, are there any other 'planets' outside solar system within 10-15 rocket speed year distance we can live in?[in 1000 years we definitely would have colonised whole of solar system - Jupiter, Mars etc.]

Next 4 are in next post...

When to give solid feed to baby

We were confused as to when to give solid feed [cerelac etc.] to our baby. We researched quite a bit and found this from The American Academy of Pediatrics very informative.

The American Academy of Pediatrics (AAP) believes that breastfeeding is the optimal source of nutrition through the first year of life. We recommend exclusively breastfeeding for a minimum of four months but preferably for six months.

 

Why plants reject green, most abundant wavelength in sun?

When we look at the solar spectrum it has its maximum around green.

 
So it is really odd, that plants reject green light  when it has the most energy. Is it simply the quirk of evolution [chlorophyll won out as the top photo synthesizer] or is there a deeper reason?

Very courteous and helpful Bangalore police!

I was pleasantly surprised when I went to Ulsoor and Indira nagar police station near me. Upto that most of my experiences in Coimbatore, Hyderabad and Guwahati were par for our country.

But when I went to Ulsoor police station I went straight to traffic police station and they very helpfully redirected me to law and order police station. In Ulsoor station they were very helpful and when I asked for a particular document they promptly gave it instead of making me run around.

In Indira nagar police station as well they were very helpful and one of the officer there actually even xeroxed one of my documents for me [can you believe that?] In fact one of the police man actually gave his seat to me [I am not an old man, BTW] for me to fill some forms along with an officer. To top it all, when I asked for Indira Nagar police station number, the officer actually gave his number and asked me to call him in case the document doesn't go through etc.

During whole of this exercise I was very pleasantly surprised by How courteous and helpful Bangalore police, particularly in these police stations are!

A real big thanks and shout out to Bangalore police!