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Physics Feedback

by Ron Kurtus

Readers have sent in a total of 820 comments and questions on Physics issues. They are listed according to date.

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

List of most recent 15 letters




I need a project on physics General Nigeria
Device using small disc magnet General Canada
Electrostatic induction and rice General India
What if matter did not change its state? Changing States of Matter Pakistan
Is pressure distributed on a bench? Pressure USA
Permission to use images Pressure and States of Matter USA
Connecting AC to terminals of a battery AC India
Why aren't mercury lamps used more often? Lighting India
Where do charges go? Basics Zimbabwe
Wants to know about particle physics General USA
Viewpoint on gravitation and Big Bang theory General Bangladesh
Give examples of using force Forces Malaysia
Using adapter between plugs AC World Voltages New Zealand
How fast is a magnetic impulse? EM Waves USA
Is time static? Time USA

Next 15 letters



I need a project on physics

September 8, 2017


I need project on physics

Abubakar - Nigeria (28222)


See our short list of Physics Experiments for some examples and ideas.

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Device using small disc magnet

September 6, 2017


Good morning Ron. My son and I are developing a low tech medical device that relies on the attraction between a small disc magnet 20 mm x 2 mm and a similarly sized flat washer. We're having a problem with the amount of attraction between the two and need to increase it and are thinking about increasing the size of the magnet or the washer but are constrained in doing this due to physical dimensions. Is there anything readily available such as a flat washer or disc with a higher than normal iron content that would cause the magnet to be more strongly attracted to it? Many thanks!

Niall - Canada (28214)


You might try a Neodymium disc magnet. They are small, strong and inexpensive and can be bouht through or other outlets.

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

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Electrostatic induction and rice

September 5, 2017


Hello sir...

Electrostatic induction or electrostatic generator that can stick with plain dry rice or not ???

daksha - India (28213)


An example of rice being affected by static electricity can be explained in Rice grains sticking to a polythene bag.

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Changing States of Matter

What if matter did not change its state?

August 25, 2017


Explain that what happened if there would be no change in states of matter?


Aamish - Pakistan (28197)


If all matter stayed in its existing state or phase, ice would not melt to become water, and water could not boil into steam. Also, there would be no evaporation of water. Just these factors alone would affect living beings in a short time.

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Is pressure distributed on a bench?

August 15, 2017


This article of you on pressure helped me greatly. But I still have some confusions. Such as-

If we apply force with the surface of our hand on a big bench then will the force be distributed throughout the whole area of the bench or it will just act on the portion of the bench equal to the area of our hand?

Dise - USA (28183)


The pressure on the bench will be just on the area where you push with your hand. Think of how a pillow will compress where you push your hand on it.

However, the force you apply can move the whole bench.

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Pressure and States of Matter

Permission to use images

August 14, 2017


I would like to use the phase diagram figures that you have on this page:

in an article that I am writing for the Health Physics Society. I understand that I need permission to use the figures. Is that possible that I could have permission to use your figures?

Thanks so much,

Linda - USA (28181)


Yes, you have permission to use the diagrams provided you cite the source.

Best wished for success in your article. Let me know when it is published.

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Connecting AC to terminals of a battery

July 26, 2017


What will happen if we connect Alternating current to the terminals of a battery?

Krishna Priya - India (28141)


You really can't charge a battery directly with AC electricity. An AC to DC adapter is needed.
It is also possible that the battery would become overheated from the AC and even explode.

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Why aren't mercury lamps used more often?

July 26, 2017


Why we use mercury lamps more often?Is there any beneficial thing about it?

Kanchana - India (28142)


A mercury-vapor lamp uses an electric arc through vaporized mercury to produce light. The light can be very bright. The advantages is that they are more energy efficient than incandescent and most fluorescent lights. One disadvantage is that they give off ultraviolet radiation, which can be harmful to the skin and eyes. Special filters must be used.

Mercury lamps are used for large area overhead lighting, such as in factories, warehouses, and sports arenas as well as for streetlights.

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Where do charges go?

July 21, 2017


where does the charges go when an object losses its static charges.

snobbo - Zimbabwe (28139)


Objects usually lose static charges on their surfaces by coming near an object with opposite charges. For example, if an object has negative (-) charges on its surface, and an object with an excess of positive (+) charges comes close, the negative electrons will jump to join with the positive charged ions to neutralize the charge.

Remember that a stable atom has a positive nucleus and negative charged electrons in orbit around the outside.

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Wants to know about particle physics

June 27, 2017


I am 70 years old. Since I've retired, I decided to enrich my brain studying science. In my studies the subject of physics was touched upon. I fell in love with particle physics! I took some chemistry about half a century ago. I would like to learn more about particle physics without going into the math. Can my poor old brain learn?

Don't know if you can answer. If not, I'll keep on searching!

Deborah - USA (28106)


It is great that you want to enrich your brain by studying the sciences. As they say, "It's never too late to learn."

I have several lessons on the basics of particle physics at Particles of Matter.

Also, you might find some articles of interest at Understanding Chemistry.

Best wishes on increasing your knowledge.

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Viewpoint on gravitation and Big Bang theory

June 19, 2017


Near about 14 billion years ago Allah/God the big bang and started evolution, now 7 divisible gravitation worlds.

“Gravitational worlds, they are moving or changing the orbit with their all family members depending on the nuclear of each other”. In this way- There has been incidence of full view of the universe at the very exact copy/invitation of the visible diagram solar system in the gravitation world. The universe has seven divisible, the first one of which is unit and the rest six are collective. The collective six gravitation are three invisible and the rest three are visible. The visible gravitation worlds are stars, planets and minor planets. The invisible gravitation worlds are black holes of various energy levels, the first one of which is the primordial black hole or Allah/God of the nuclear fusion of the universe. There have been collective six gravitation divisible of the big bang in future from the big black hole or Allah/God. At the first phase or level of the divisible is the black hole of the nuclear fusion of the clusters of galaxies or black hole named quasar. The second phase gravitation world of the quasars in future are of the black hole named pulsar or nuclear fusion of the cluster of galaxies. The third gravitation world of the pulsars in future is of the last black holes or nucleus of galaxy or the nuclear fusion of the constellations.

New Discovery of the Universe:

Pope: The most important news- about the God, Big Bang & Evolution at

Shahidur Rahman - Bangladesh (28099)


Thanks for the information and interesting viewpoint on gravitation.

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Give examples of using force

June 12, 2017


Name one examples when force can stop motion.

Name one examples when force can change the shape and size of an object

Nicholas - Malaysia (28088)


You can push on a rolling cart to stop its motion.

You can compress a foam rubber ball to change its size and shape.

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AC World Voltages

Using adapter between plugs

June 11, 2017


can I use an appliance from south Korea - 220v in New Zealand 230v ? from your chart it would also appear that the frequency will be different also will this cause problems? thirdly the plug types are different is it ok for an electrician to change the plug from c to l

Tina - New Zealand (28086)


The voltage difference should not affect things. However, a 60Hz appliance might perform slower with 50Hz. If there are timers or clocks involved, it might make a difference. It is good to check with the manufacturer website to see if things would work sufficiently.

An adapter plug could be used if the prongs are different. An electrician should be able to make the proper connections.

Best wishes for successful use of your appliance.

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EM Waves

How fast is a magnetic impulse?

June 3, 2017


Have the effects of magnetism (attraction-repulsion) ever been quantified into speed? How fast is a magnetic impulse?

James - USA (28072)


Magnetic, electrical, and gravitational impulses all move at the speed of light. Typically, a magnetic disturbance will cause an electrical disturbance, resulting in an electromagnetic wave, which also travels at the speed of light.

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Is time static?

June 2, 2017


Love your site, Thank You!

Subject: Relativity/Time
We humans understand time as past, present and future.
The Past is our Memory
The Present is our Current Condition
The Future is our Expectation

Is it possible that Time is static?

We exist in a series of static universes that we register as the duration or "flow" of time.
Even at Planck time there is duration.
Duration is change in the Universe.
By splitting any change into time segments, every change has a beginning, a duration and an ending.
Even the emission of a photon.
It is a static photon, it starts to move, continues to move and stops moving when acted upon or reaching the desired destination (Planck Length).
During the moment when it starts to move there is duration between its static point and its next static point.
There is even duration between the change of static points. Like a buildup to change similar to a potential charge of time. I'll call it a Duriton.
Duritons occur faster than can be measured by our technology. Just because something can't be measured doesn't mean it can't exist.
Our lives are a series of duritons that we register on a massive scale to simulate continuity.
Is it safe to say that we exist in a constant flow of individual duritons, remembering the past as the present?

Thank you.

tMic - USA (28069)


The whole concept of time is difficult and complex.
As far as humans go, the sensing of time seems to vary with age. See Sensing Time. Thus, is time different for different people?

At the quantum level of matter, movement is in "quantum jumps" instead of being continuous. Likewise, since time is related to motion, it too could be in quantum increments. Thus, you could think of time being static in between those jumps. Your idea of a "Duriton" might fit within that area.

In some theories, time is considered a fourth dimension. It can curve just as space can curve.

Keep up the good work in pondering these issues.

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