Search found 15 matches

by adhiluhur
Mon Sep 05, 2011 12:56 pm
Forum: Physics Questions
Topic: Physics Competition
Replies: 3
Views: 2052

Physics Competition

Hi.
Just wondering are there any Physics/Mechanics Competition coming up?
Does Joe usually put announcement about this?
by adhiluhur
Thu Jul 07, 2011 6:24 pm
Forum: Physics Questions
Topic: Meteors and meteorites
Replies: 1
Views: 1464

Meteors and meteorites

Meteor: Quite Interesting. From various science fiction movies meteors when hitting Earth always portrayed in hot condition. However if you think about it, space temperature is near absolute zero, do you think they should be freezing when reaching Earth? Rocks are poor conductors of heat, even thou...
by adhiluhur
Thu Jun 30, 2011 12:21 am
Forum: Physics Questions
Topic: Does Higher Temperature Water Freeze Faster?
Replies: 12
Views: 2830

Re: Does Higher Temperature Water Freeze Faster?

A number of possible explanations for the effect have been proposed, but so far the experiments do not show clearly which, if any, of the proposed mechanisms the most important one is. While it is often to hear confident claims that X is the cause of the Mpemba Effect, such claims are usually based ...
by adhiluhur
Thu Jun 30, 2011 12:18 am
Forum: Physics Questions
Topic: Does Higher Temperature Water Freeze Faster?
Replies: 12
Views: 2830

Re: Does Higher Temperature Water Freeze Faster?

Supercooling (water freezes not at 0°C, but at some lower temperature) may be the answer. This would mean that the initially warmer water might freeze first because it would freeze at a higher temperature than the initially cooler water. Even if this true (I have neither knowledge nor understanding ...
by adhiluhur
Thu Jun 30, 2011 12:18 am
Forum: Physics Questions
Topic: Does Higher Temperature Water Freeze Faster?
Replies: 12
Views: 2830

Re: Does Higher Temperature Water Freeze Faster?

Moreover, why should the water be around 35 C? Isn't it better to have, say 50 C? Furthermore, even though the higher temperature=stronger convention current, faster cooling is irrelevant because as the cooling taking place, the convention current become less and less strong. Its like saying cold wa...
by adhiluhur
Wed Jun 29, 2011 11:59 pm
Forum: Physics Questions
Topic: Does Higher Temperature Water Freeze Faster?
Replies: 12
Views: 2830

Re: Does Higher Temperature Water Freeze Faster?

...To get the best results, this water should be about 35 degrees Celsius. If it's too hot, add cold water in small amounts while stirring and checking the temperature with the thermometer. … In the hot water container a strong convection current forms due to the big temperature difference between ...
by adhiluhur
Wed Jun 29, 2011 11:56 pm
Forum: Physics Questions
Topic: Does Higher Temperature Water Freeze Faster?
Replies: 12
Views: 2830

Re: Does Higher Temperature Water Freeze Faster?

i learnt about this via science by email in 2010, which is run by CSIRO here is the link to the experiment and explanation they gave. hopefully you'll find it more reliable and englightening than wiki. http://www.csiro.au/helix/sciencemail/activities/freezinghot.htm I've read the article, however i...
by adhiluhur
Wed Jun 29, 2011 10:21 pm
Forum: Physics Questions
Topic: Does Higher Temperature Water Freeze Faster?
Replies: 12
Views: 2830

Re: Does Higher Temperature Water Freeze Faster?

angle.alpha wrote:wiki once again has other a variety of explanations

I also wiki'ed it but do you know that Wikipedia can be edited by anyone, including me and yourself?
Unfortunately, UNSW does not has article about this.
by adhiluhur
Wed Jun 29, 2011 4:11 pm
Forum: Physics Questions
Topic: Unusual Globe
Replies: 0
Views: 2057

Unusual Globe

I've read an article about a quite interesting globe. In London, on 19th Century there was a full representative of the Earth, including all the land masses, the sea, mountains, rivers, all interior surface built to scale. The globe was 18 m in diameter. The interesting part was public need to go IN...
by adhiluhur
Wed Jun 29, 2011 3:33 pm
Forum: Physics Questions
Topic: Does Higher Temperature Water Freeze Faster?
Replies: 12
Views: 2830

Does Higher Temperature Water Freeze Faster?

I've read an article about Mpemba Effect that warmer water freeze faster. It was first observed by a 13 years old student from Tasmania, Erasto Mpemba. When he presented this phenomenon, he was ridiculed by his classmates and teacher. But later on Dr. Denis G. Osborne visited his school, experimente...
by adhiluhur
Sat Jun 25, 2011 9:58 pm
Forum: Physics Questions
Topic: Negative and Absolute Hot Temperature
Replies: 2
Views: 1656

Negative and Absolute Hot Temperature

Absolute zero is term used to describe the state when no heat present, (which is impossible). It comes to my mind, is there any limit of the highest temperature can achieve? I tried google and it said that the highest possible temperature is Plank Constant. How come temperature has end limit? How ab...
by adhiluhur
Fri Mar 11, 2011 5:55 pm
Forum: Physics Questions
Topic: Does light have gravity
Replies: 16
Views: 7957

Re: Does light have gravity

Will light exert pressure on the every object it touches?
by adhiluhur
Fri Mar 11, 2011 3:50 pm
Forum: Physics Questions
Topic: Does light have gravity
Replies: 16
Views: 7957

Re: No and yes

but i thought that light only had mass due to its velocity Light has no mass. I don't think it is entirely true. I know that light is composed of massless particle (photon). However, if the light is trapped inside box of mirror so the light travels back and forth simultaneously, the total momentum ...
by adhiluhur
Fri Mar 11, 2011 3:28 pm
Forum: Physics Questions
Topic: Does light have gravity
Replies: 16
Views: 7957

Re: Does light have gravity?

Uttaran wrote:I think since light is a form of energy it doesn't have mass and so it cannot have gravity.


Remember the famous equation E=mc^2. This equation say that whenever there is energy, there is mass and vice versa.
by adhiluhur
Fri Mar 11, 2011 3:13 pm
Forum: Physics Questions
Topic: Does light have gravity
Replies: 16
Views: 7957

Re: Light+Mass == c>3E8 or c<3E8

If the light affected by gravity, then it must has a known mass and in that case the constancy of light is violated and that is what i think the case in some region in the universe. There must be no such thing like "a particle with rest mass of zero" it is just not possible!! Any particle...

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