by Ron Kurtus
Readers have sent in a total of 4978 comments and questions on Science issues. They are listed according to date.
You can read them to further your understanding of the subject.
|Units of pressure and force||Pressure||India|
|Water pressure when stones added to a pool||Pressure||UK|
|Gas pressure on .5 square inch area||Pressure||Pakistan|
|Animal and plant groups||General||USA|
|Applying a torque||Force and Torque||Myanmar|
|Why does light change its speed?||Refraction of Light||Pakistan|
|Define refraction||Refraction of Light||Pakistan|
|How can we cool the Earth?||Heat Transfer on Earth||USA|
|Why does light separate into colours?||Dispersion of Light||Pakistan|
|How is physical science related to geology?||General||Nigeria|
|How does a vacuum in a thermos prevent heat transfer?||Heat Transfer||Tanzania|
|Need glass that blocks infrared||Heating a Greenhouse||India|
|Transverse electromagnetic waves||EM Waves||Philippines|
|Definition of force at a distance||Force at Distance||USA|
|Can understand maths but not science||General||SA|
Units of pressure and force
July 13, 2017
Why pressure and force unit is same?
Pratik - India (28131)
Pressure is force per unit area: P = F/A.
Units are Pascal = Newtons per square meter
Water pressure when stones added to a pool
February 9, 2017
Ron, Thanks for your article. what happens to water pressure if some of the water is removed and replaced by stones. In a pool. I think the water pressure at bottom of pool is reduced.
Kieran - UK (27870)
Water pressure is caused by the weight of the water above the point of measurement. If the pressure is measured in grams per square cm, it would be the weight of the column of water 1 square cm times the height.
This would be true for water pressure at the top of the stones. Since the distance to the surface is reduced, the water pressure would be less at that point than at the bottom with no stones.
Gas pressure on .5 square inch area
January 13, 2017
what will the gas pressure on .5 square inch area if the pressure is 10 psi in a container of gas.
asif - Pakistan (27801)
"psi" stands for "pound per square inch". If the area is 0.5 square inch, the pressure would be 5 pounds.
Animal and plant groups
January 4, 2017
1. 10 animal groups
2. 10 plant groups
Jesus Ramon Neopolo - USA (27783)
Applying a torque
November 7, 2016
Hi,i'm a student sir.
I want to know, what can we do if we know the torque?
Zarni - Myanmar (27475)
Torque is the rotational force on a shaft. This can be used to turn a wheel or other object or simple machine. If you know the torque being applied, you can calculate how well the force is applied.
Why does light change its speed?
November 6, 2016
Why When light passes from one transparent medium to another it changes its speed and direction?
sadia - Pakistan (27462)
The speed of light is different in different materials. Often it is related to the density of the material. For example, water is more dense than air and thus is slower in water. This is called the index of refraction and is related to bending at an angle.
November 6, 2016
Can I define refraction
sadia - Pakistan (27463)
Refraction of light is when it bends when going from one transparent material to another at an angle. When light goes from air to glass at an angle, it bends or refracts.
How can we cool the Earth?
October 27, 2016
So how can we humans get rid of heat on our planet and cool the earth?
David - USA (27420)
There really isn't a way for us to cool the Earth, but humans can prevent or slow down global warming, which is caused by the "greenhouse effect" of excess carbon dioxide in the atmosphere.
See Infrared, Gases and the Greenhouse Effect and Heating a Greenhouse for some explanations.
Eliminating burning of carbon-based products would help a lot. However, it is almost impossible to get people to stop using their gasoline-powered automobiles and other such items.
Why does light separate into colours?
October 3, 2016
Q1 . why white light changes into different light Q1, whith outuse of prism why white light looks white ?and use of prism why white light distrtibute in different colours of light?
hasher - Pakistan (27342)
The light you see--like from a light bulb--actually consists of all of the colours in the spectrum, but it appears white because your eyes average out all the colours.
But one characteristic of light waves is that the different colours or wavelengths travel at different speeds when moving through glass. For example, red light travels faster in glass than green light, and green light travels faster than blue light. Thus, in a glass prism, the colours separate according to their speed through the glass.
How is physical science related to geology?
July 28, 2016
What are the aspect of physical science related to geology and what are the hints in study physical science
Effiong - Nigeria (27176)
Physical Science concerns the various sciences that are not related to life. Geology is the study of solid Earth, the rocks of which it is composed, and the processes by which they change. It is sort of the history of the Earth.
A good resource is at Geology.com, which gives information on many aspects of the science.
Best wishes for success in your studies.
How does a vacuum in a thermos prevent heat transfer?
July 19, 2016
Please l need some clarification on
vaccum in themos prevent heat transfer by which way
peter - Tanzania (27155)
Much of heat or thermal energy is transferred through the vibration of high energy molecules affecting low energy molecules. In other words they heat up the molecules.
But if there is a vacuum, there are no molecules to heat up. The vacuum acts to block the heat transfer.
However, some heat transfer comes from infrared radiation. That is why a thermos usually has a shiny interior, in order to reflect the radiation and eliminate the heat transfer.
Need glass that blocks infrared
July 17, 2016
I'm working on project on solar distillator. So I need a glass which transmits the solar radiation into the box, but blocks the infrared to escape out. Do you have any idea about that glass or coatings..?!
Hemant - India (27153)
Standard window pane glass will work fine. For a background on different materials, see Best Materials for a Greenhouse Roof.
Best wishes for success in your project.
Transverse electromagnetic waves
July 3, 2016
is transverse wave and transverse electromagnetic wave the same? if not what is a transverse electromagnetic wave? how can you describe it.
fritzie - Philippines (27117)
The wave motion of an electromagnetic wave is transverse. It is similar to wave motion you can create with a rope, except that the EM wave is in three-dimensions. There are other examples of transverse waves in Overview of Wave Motion.
I hope that helps. Best wishes on your studies.
Definition of force at a distance
June 18, 2016
definition of force at a distance?
- USA (27090)
Most forces require direct contact, but there are some forces that act when the object are separated--even at great distances. A good example is gravitation, where there is a pull from very great distances. Magnetism is also a force at a distance, since the magnets act on each other when separated.
Can understand maths but not science
June 16, 2016
I would be happy to know what makes me to understand maths clearly and not to understand physical science concepts? well I do not understand anything since the beginning of the year of my grade 12 but now I would love to change and I'm asking for help so I can make it this year with distinctions in this subject.
kgomotso - SA (27084)
Mathematics is fairly abstract. so you must have more ability in dealing with numbers and abstract concepts.
On other other hand, Physical Science primarily concerns real objects and their properties. Observation of objects around you and how they behave under different circumstances is valuable in understanding the various science concepts.
Advanced Physical Science starts becoming more and more mathematical, where formulas and equations are used to describe and predict how object behave. If you are good in the maths, you should have an advantage on others in Physical Science.
I hope that helps. Best wishes in excelling in Physical Science. I am sure you will.
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