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Each day readers send in questions and feedback concerning the various lessons in the School for Champions website. A total of 15676 letters have been answered. They are listed according to date.

You can read them to further your understanding of the subjects.

List of next 15 letters





Hears constant noises in house Sound New Zealand
How is Braille used to extend vision? Senses Jamiaca
Static electricity and combing hair Physics Canada
Center of gravity of a rectangular block Gravity Bangladesh
Pulling glass sheets and water apart Experiments Physics South Korea
Increasing efficiency through use Machines Nigeria
Reducing static on a trampoline Physics Static Electricity USA
Wants scholarship in Physics Astronomy USA
Reviewer needs to spend $50 to review my book Publishing USA
When dunking was illegal Sports USA
Make a bigger quiz Force USA
Movement of pendulum Motion USA
Astronomy in the Quran Religion USA
Do grades of steel and magnetic properties Magnetism USA
Increasing 6th sense Senses India

Next 15 letters


First 15 letters

Hears constant noises in house


January 2, 2017


This is completely a shot in the darkbut you just miight be able to help. I hear a constant 24/7 noise in my small home like a low density generator or a car idling. It never changes volume and never stops night and day. By turning off all of my power, it is still there. I dont hear it outside or in the neghbours home. It is driving me crazy,and although electricinas have had a look around they can't identify the source and in fact nobody else has heard it as yet. Believe me, I am not imagining it, and I get so upset when ask others if they can hear it and they can't but you really need to be here for a considerable while before it would be noticeable to you, its more like a background noise. Who could I get to try to discover the source. I live in a smallish New Zealand Town. Is there someone who I could get to test around the place etc for noise. Many thanks.

BARBARA - New Zealand (27779)


I'm sorry to hear you have that problem with annoying background noise. It is difficult to pin down the source of the noise. Here are some thoughts on the matter:

In our house, we can hear the din of road noise from cars driving on a road about a block away. We can't hear the noise outside but can hear it in the house. It is like it focuses to the house.

High power electrical lines can have a constant buzz. However, you would also hear them outside and at your neighbors.

Is it possible there is some water running through city sewer pipes that are near your house and can cause some noises?

I don't know if those ideas will help, but I hope you can solve your noise problem.

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How is Braille used to extend vision?


January 2, 2017


How does Braille extend the sense organ?

Meg - Jamiaca (27780)


Braille is primarily used by those who are blind or have every poor vision as a way to read written material. It could be considered a "device" that extends the ability to read. However, it does not extend vision or the ability to see.

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Static electricity and combing hair


January 1, 2017


Why would it be better to comb hair with aluminum comb rather than plastic comb to avoid build up of static charge?

Thank you

Sam - Canada (27770)


Human hair and aluminum combs both tend to give up electrons, while a plastic or hard rubber comb attracts electrons and thus attracts the hair. See Materials that Cause Static Electricity.

Also see Controlling Flyaway Hair from Static Electricity.

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Center of gravity of a rectangular block


January 1, 2017


how to calculate center of gravity of a rectangular block?

Jayanta - Bangladesh (27771)


If the block is made of a uniform material and is perfectly rectangular, the center of gravity is the geometric center of the block. That is, half the way from each end.

Otherwise, you can measure the center of gravity experimentally by hanging the block from each corner and marking the sides with a plumb line. The intersection of the lines is the COG.

I hope that helps.

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Pulling glass sheets and water apart


December 30, 2016


Hello. I am currently a high school student in South Korea. I was assigned to conduct a physics research project in school, but I really cannot even get started on solving it. I read some lessons on your website, and I was wondering if you could help me.

The question is: Investigate the various forces involved when you try to separate two sheets of glass separated by a thin layer of water.

So far, I've found that two main forces will work to make separating the glass harder. First is the fact that you have to break the bonds within the film of water to separate the two sheets, and the second is that sandwiching water between the two sheets creates a pseudo- vacuum which means that air pressure will be pressing down in all directions, and that is what makes separating them harder.

Any and all help will be appreciated. You could basically send me a few key terms to help me get my research started, or send me the name of a research paper, or suggest ways for me to get an experiment designed, and have my gratitude forever.

Thank you in advance!

Hojin - South Korea (27725)


If you try to pull the glass sheets apart, keeping the surfaces parallel, vacuum areas will be created within the water. Atmospheric pressure will push the glass sheets together. That pressure is much greater than the adhesive bond of the water on the glass.

However, if you pull the glass sheets apart at an angle--almost like peeling them apart--the only forces will be from the water adhering to the glass.

I am sorry, but I don't know of any research papers that you can refer to.

Best wishes for success in your research project. I am sure you will do a great job at it.

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Increasing efficiency through use


December 26, 2016


Can the efficiency of a machine increases through consistent use or frequently ?

Felix - Nigeria (27581)


Factors that can reduce the efficiency of a machine are friction and heat build-up. In some machines, friction may be increased if it is not used often. This can be due to oxidation of the surfaces. In such a case, using the machine more often can reduce or eliminate this type of friction, thus increasing its mechanical efficiency.

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Reducing static on a trampoline


December 23, 2016


My trampoline has a safety net surrounding it.I put my water hose on jet spray and cleaned the net.That got rid of the static instantly. Now the kids can play on it in peace. The accumulation of dust on the screen was the problem.

Ernestine - USA (27578)


Thanks you for your information on solving the problem of build-up of static electricity on a trampoline.

I am sure our readers will appreciate knowing about your method.

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Wants scholarship in Physics


December 19, 2016


how I get free scholarship by physics?

Minale - USA (27575)


Most high schools have lists of scholarships available. Your physics or astronomy teacher should also be able to provide help in getting a scholarship.

Some websites to check include:
SPS Scholarships
Scholarships for Physics Majors

Various colleges also have information on getting a scholarships.

Best wishes for your success in getting an education.

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Reviewer needs to spend $50 to review my book


December 17, 2016


people who buy my books say they try to write a review say they can't unless they join and have spent $50.00. Why?

Jeanne - USA (27572)


I know that in order to submit a review the person needs to get an account with Amazon for purchasing item. But I haven't seen anything about them having to spend $50 on books or goods before they can submit a book review.

Amazon seems to be jacking up the prices and looking at new ways to make money. I know that they recently increased the yearly fee for their Advantage program from $29.95 to $99/yr. That is a steep jump.

Best wishes in selling your books, either on Amazon or through other outlets.

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When dunking was illegal


December 14, 2016


So now I want to know WHY the rules were changed to make dunking legal? And who was the player to first start dunking again?

- USA (27567)


The NCAA started the "Alcindor Rule" in 1967 because they felt he would dominate the sport too much, although there had been many other big men who dunked before Alcindor. The NCAA officials finally realized that the public liked to see players dunk, and there were many college basketball players that could dunk. So the decided to get rid of the rule.

David Thompson of NC State dunked in his last college game, but it was just before the rule changed. So he was given a technical foul.

I'm not sure who was the first to dink when it was legal.

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Make a bigger quiz


December 14, 2016


Make that a bigger quiz please.

Nick - USA (27569)


Thank you for the suggestion. I'll try to add more questions.

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Movement of pendulum


December 13, 2016


How to determine the periodic movement of a simple pendulum?

Fermin Saw - USA (27562)


See Demonstration of a Pendulum to see an example of how a pendulum moves.

Equations for a Simple Pendulum will show how to calculate the periodic motion.

I hope that helps. Best wishes in your studies.

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Astronomy in the Quran


December 10, 2016


Greetings, I immensely thank you for your wonderful physics website, it is very helpful. I want your opinion about scientific and astronomical facts that I have found in a book dating back to more than 1400 years, check some of them:
Creation of the Universe, "Big Bang"
“Do not the Unbelievers see That the heavens and the earth Were joined together (as one Unit of Creation), before We clove them asunder?”
[Al-Qur’aan 21:30]
That there was a huge gaseous matter or clouds were present before the formation of the galaxies.
“Moreover, He Comprehended In His design the sky, And it had been (as) smoke: He said to it And to the earth: ‘Come ye together, Willingly or unwillingly.’ They said: ‘We do come (Together), in willing obedience.’”
[Al-Qur’aan 41:11]
The Light of the Moon is reflected light.
“Blessed is He Who made Constellations in the skies, And placed therein a Lamp And a Moon giving light.” [Al-Qur’aan 25:61]
The Arabic word for the sun in the Qur’aan, is shams. It is referred to as
siraaj, which means a ‘torch’ or as wahhaaj which means ‘a blazing lamp’ or as diya which means ‘shining glory’. All three descriptions are appropriate to the sun, since it generates intense heat and light by its internal combustion.
The Arabic word for the moon is qamar and it is described in the Qur’aan as muneer, which is a body that gives nur i.e. light. Again, the Qur’aanic description matches perfectly with the true nature of the moon, which does not give off light itself and is an inert body that reflects the light of the sun.
Not once in the Qur’aan, is the moon mentioned as siraaj, wahhaaj or diya or the sun as nur or muneer. This implies that the Qur’aan recognizes the difference between the nature of sunlight and moonlight.
The Sun Rotates
“It is He Who created The Night and the Day, And the sun and the moon: All (the celestial bodies) Swim along, each in its Rounded course.”
[Al-Qur’aan 21:33]
The Arabic word used in the above verse is yasbahûn. The word yasbahûn is derived from the word sabaha. It carries with it the idea of motion that comes from any moving body. If you use the word for a man on the ground, it would not mean that he is rolling but would mean he is walking or running. If you use the word for a man in water it would not mean that he is floating but would mean that he is swimming.
Similarly, if you use the word yasbah for a celestial body such as the sun it would not mean that it is only flying through space but would mean that it is also rotating as it goes through space. Most of the school textbooks have
incorporated the fact that the sun rotates about its axis. The rotation of the sun about its own axis can be proved with the help of an equipment that projects the image of the sun on the table top so that one can examine the image of the sun without being blinded. It is noticed that the sun has spots which complete a circular motion once every 25 days i.e. the sun takes approximately 25 days to rotate around its axis.
In fact, the sun travels through space at roughly 150 miles per second, and takes about 200 million years to complete one revolution around the center of our Milky Way Galaxy.
“It is not permitted To the Sun to catch up The Moon, nor can The Night outstrip the Day: Each (just) swims along In (its own) orbit (According to Law).”
[Al-Qur’aan 36:40]
This verse mentions an essential fact discovered by modern astronomy, i.e. the existence of the individual orbits of the Sun and the Moon, and their journey through space with their own motion. The ‘fixed place’ towards, which the sun travels, carrying with it the solar system, has been located exactly by modern astronomy. It has been given a name, the Solar Apex. The
solar system is indeed moving in space towards a point situated in the constellation of Hercules (alpha Layer) whose exact location is firmly established.
The moon rotates around its axis in the same duration that it takes to revolve around the earth. It takes approximately 29½ days to complete one rotation.
The Sun will extinguish after a certain period
“And the Sun Runs its course For a period determined For it; that is The decree of (Him) The exalted in Might, The All-Knowing.”
[Al-Qur’aan 36:38]
The Arabic word used here is mustaqarr, which means a place or time that is determined. Thus the Qur’aan says that the sun runs towards a determined place, and will do so only up to a pre-determined period of time – meaning
that it will end or extinguish.
The Book's name is "Quran", as mentioned it was revealed to Prophet Muhammad.
Muhammad, the prophet of Islam was an unlettered man, he could not write nor read his own name. Islam in Arabic means: Total submission to God's will (not a follower of Muhammad).
It is a monotheistic religion, and it obligates it followers to believe in all the previous prophets such as Jesus, Moses, Noah, Abraham etc, and not worship any of them, rather, worship their Creator.
There are chapters entitled by the names of some of them, in addition to a chapter name called "Maryam" translated "Marry" in the honor of the mother of Jesus.
Regardless of these scientific facts, there are still many that I did not mention (such as the Universe expanding and many others!),
please care to read them if your interested, there are books that lists the scientific miracles in the Quran, one of the best:
"The Quran and Modern Science Compatible or Incompatible ?"
Please if you have any questions ask me, thank you. Again.

Mozhar - USA (27556)


Thank you for your insight on scientific and astronomy references in the Quran. These were written in the "glory days of Islam" in about 800, where Islam was the world leader in scientific studies.

I do have a article on Big Bang Theory and Religion that references mention in the Quran.

Best wishes for success in your studies.

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Do grades of steel and magnetic properties


December 9, 2016


Do different kinds of commercially available steel sheets have different magnetic properties?

We make magnetic glass dry-erase boards, and I'm wondering if I could substitute a different steel sheet that would make my magnets work better through the glass surface.

Aaron - USA (27554)


An iron sheet might work better than steel. Iron gets magnetized faster but loses its magnetism as soon as the inducing magnet is removed. On the other hand, steel is slow to be magnetized but retains the acquired magnetism for a long time.

If an iron sheet is not possible, a lower-grade steel sheet should react better than a high-grade steel sheet.

I hope that helps. Best wishes for success with your product.

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Increasing 6th sense


December 8, 2016


how can we increase our six sense of sensing any bad incidence in future. I experienced and it became true. I want to increase this sense

Shubham - India (27547)


You might look at Checking Your 6th Sense for some information in increasing that ability.

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