Practical Innovations that changed the world!

1. Faraday's discovery of induced current from changing magnetic flux which runs our economy now. Think of a world without electricity - no light, no tv, no laptop and no internet!
2. Graham Bell's invention of Telephone - It totally changed the way we communicate. Precursor to this is Telegram and Cellphone is successor.
3. James Watt's Steam Engine and Trains - it changed the way people move.
4. Wright brothers' invention of air planes - of course, it also changed the way we move.
5. Computers - it changed the way people do work, buy, entertain. All kinds of reservations, shopping and great scientific endeavours like 'curiosity'.
6. Ability to make controlled fire. It changed the way we eat or build things.
7. Agriculture - It again changed the way we eat.
8. Ability to forge metals.
9. Counting in base 10.

 Did I miss something more important?

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...