by Ron Kurtus
Readers have sent in a total of 4980 comments and questions on Science issues. They are listed according to date.
You can read them to further your understanding of the subject.
|Why is the atmosphere mostly heated by the earth?||Heat Transfer on Earth||Tanzania|
|How do I buy these lessons online?||Force and Torque||New Guinea|
|How does Physical Science apply to life?||General||South Africa|
|Why is ozone layer depleting?||General||Pakistan|
|How we can get rid of pollution?||General||Pakistan|
|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|
|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|
Why is the atmosphere mostly heated by the earth?
March 30, 2018
Why atmosphere is mostly hearted by the earth rather the sun
Halifa - Tanzania (28492)
Since the atmosphere is basically transparent, it is not heated much by the sunlight. However, the dark soil absorbs the radiation and become heated. Then air in contact with the ground gets heated through conduction. Then the other air is heated by convection.
Sunlight heating the ocean is not as effective as heating the ground, but it still is better than the air.
How do I buy these lessons online?
March 23, 2018
How do I buy these lessons online? I don't have a bank card, please advise
James - New Guinea (28484)
You can use all of the lessons at no charge to you. I hope they help you in your studies.
How does Physical Science apply to life?
January 29, 2018
How to really understand physical sciences and adapt to it in everyday life
Thapelo - South Africa (28408)
Physical Science includes Chemistry, where you can see how materials combine. It also includes Physics, where you can see how energy affect things and causes motion.
When you understand what causes things, you can then get an idea of how it applies to everyday life. See Physical Science Overview for more information.
Best wishes in your studies.
Why is ozone layer depleting?
September 19, 2017
Why ozone layer is depleting and what can we do to recover it?
Aamish - Pakistan (28240)
The ozone layer or ozone shield is a region of Earth's upper atmosphere that absorbs most of the Sun's harmful ultraviolet radiation. Unfortunately, some chemical compounds, such as chlorofluorocarbon and Freon, used in air conditioners and refrigerators break down the ozone.
The Montreal Protocol is an international treaty designed to protect the ozone layer by phasing out the production of numerous substances that are responsible for ozone depletion.
Slowly over the years, the ozone layer has been recovering.
How we can get rid of pollution?
September 19, 2017
Q.1 How you are contributing in pollution causing agent.
Q.2 How we can get rid of pollution.
Q.3 Why there is much pollution in Pakistan.
Aamish - Pakistan (28244)
Causes of pollution include older automobiles that don't have pollution controls, factories that emit smoke and pollution, and people who burn items with no controls.
Government controls are usually required to reduce polluting automobiles and factories. Education of the public is also necessary to eliminate pollution-causing fires, such as burning trash and even tires.
Many countries--including Pakistan--are struggling with ways to reduce their pollution.
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.
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.
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