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Showing posts from January, 2011

The Physics of Whip Cracking

I tried my hands on whip cracking in an Aussie sheep farm tour late last year.  Interestingly, whip cracking in Australia has gained enough prominence to be a competitive sport! I must admit that the whip is not my forte, as I could only get it cracking 10% of the time (when I am not hitting myself with it).  Staring at defeat, I decided to learn the science behind this in hope of conquering it some day. It turns out a whip cracks because a sonic boom is created at its tip or topper. A sonic boom is created when an object travels at supersonic speeds such that its surrounding waves of air pressure are compressed into a single shock wave at the speed of sound. The logical question then: what is travelling so fast in the whip? Well, it's the tip. Why? Conservation of momentum! Let's picture this: when you apply a force to a whip, the initial loop motion and wave are applied to the thong, which has a much larger mass than the whip's tip. It is worth noting that momentum i

Prime Numbers and Encryption

Want to make   \$250 000 ?  Find a big prime number, a really big one. It turns out there are organizations  ready to dough out good cash for a really large prime number.  This is because primes are used in   RSA cryptography . RSA Algorithm Let's look at the algorithm: 1.       Multiply two large prime numbers  p  and  q  to get the product  N 2.       Find two numbers  e  and  d , such that  ed = 1mod((p-1)(q-1)) , where  e  and  N  are relatively prime meaning they do not share any prime factors. 3.       Let's call  M  the original message and  C  the ciphered message:  a.       To encrypt: C = M e mod(N) b.       To decipher: M = C d mod(N)  In essence, using the public key   ( N,e)  will transform the original message   M   to the ciphered message  C . On the contrary, applying the private key  d  on the ciphered message   C  will result in the original message   M .  Security of Encryption The beauty of RSA is your public key can be published for anyone to

The Colours of Water - From The Caribbean to the South Pacific

Last year, I took a number of vacations which involved cruising, diving, snorkelling and walking on glaciers. Thinking back on those trips, I could not help but notice that water and ice exhibited different colours in different settings.  I decided to dive deeper into the colours of water. Finally, here are my findings. Water’s True Colour The colour of an object mainly depends on the colour of light emitted from it. In the case of water its colour is also affected by factors like light source, absorption, scattering, and suspended materials. Absorption by water is stronger for red light, but weaker for blue light. Water is therefore, intrinsically blue. However, this effect is only apparent when the water is reasonably deep. This is why a glass of water appears colourless whereas a big aquarium looks bluish through the thickness of water. Why is the Sea Blue? I did two cruises last year, one in the Caribbean and the other in the South Pacific. Owing to the depth of the water, t

2011 New Year Resolutions

Happy New Year!  I fell prey once again to the 9 - 5 in December. Combined with the year end holiday season,  this blog saw very little action last month. However, my resolution this year is to post one article each week to make this blog an interesting read for all of you out there! I know they say that resolutions are made to be broken, but I have a great feeling about this one. See you all next week! -PTS