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by Ron Kurtus

A total of 250 comments and questions have been sent in. They are listed according to date.

List of next 10 letters




Atom as Solar System Tests can rule out the atom as a solar system USA
Changing States of Matter Examples of changing solids to liquids Australia
Atoms Electron cloud around an atom Egypt
Kinetic Theory of Matter Explain vividly the kinetic theory of matter Nigeria
Atom as Solar System Concept of an atom inside an atom India
Floating Why do some fruits float in water? India
Snow Why are high clouds gasses at extremely low temperatures? Canada
Floating Metal with same density as liquid India
Density Biscuit absorbs water and sinks India
Changing States of Matter Why is mercury a liquid at room temperature? USA

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First 10 letters

Tests can rule out the atom as a solar system

Topic: Atom as Solar System


March 31, 2015

By making the assumption that our solar system or other's is a bigger atom,could tests be done on existing atom's to rule out this idea or to prove it.if so could it prove that quantum theory is huge compared to how much farther we need to see to understand the universe/'s?




Considering an atom as being similar to a solar system is an interesting idea, but when looking at the physical laws, it really does not hold up, especially when you bring in quantum mechanics.

But likewise, solar systems might be forms of "atoms" within a galaxy "molecule".

It is all speculation and probably can be readily disproved. But it makes for some interesting thoughts.

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Examples of changing solids to liquids

Topic: Changing States of Matter


March 16, 2015

Hi! I'm teaching gr 5 science and I wanted to bring cooking into our discussion on changing states of matter. We've talked about ice melting and water freezing, but I'm looking for some more interesting examples.

Can I talk about a solid chocolate bar melting into a liquid?

Is baking a cake the same principle as turning a liquid into a solid?? That's using heat, so I don't think it is, but then, what is it??

Any suggestion for using food in the science classroom would be wonderful!
Thanks very much.

Lara - Australia



Volcanoes change solid rocks into liquid magma. Melting chocolate is a good example changing states. Also, when you heat the chocolate, you can smell the fumes, which are chocolate molecules in the gaseous form.

Burning a candle changes the solid wax to liquid wax. The flame is the burning of the was gas.

Baking a cake is an example of using heat to cause a chemical reaction, such that the liquid mixture combines chemically to create a different composition.

I hope this helps. Best wishes with your class.

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Electron cloud around an atom

Topic: Atoms


February 28, 2015

why the electron cloud make the atom more stable?

Mohamed - Egypt



A stable atom should have an equal number of negatively charged (-) electrons and positively charged (+) protons.

The simple theory states that the electrons rotate around the nucleus. Newer theories say that the electrons spread out in a form of cloud. However, the number of (-) charged should still equal the number of (=) charges.

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Explain vividly the kinetic theory of matter

Topic: Kinetic Theory of Matter


January 26, 2015

1. Explain vividly the kinetic theory of matter.

2. What are the two forces that acted on the Particles of matter.

SIMEON - Nigeria



The Kinetic Theory of Matter states that matter consists of atoms and molecules that are in constant motion. That means they have kinetic (or moving) energy.

Forces acting on the particles of matter include molecular attraction, magnetic, and electrical forces. There are also forces caused by the collisions between the particles.

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Concept of an atom inside an atom

Topic: Atom as Solar System


January 26, 2015

I have a opinion that the concept is about atom inside atom.its all about size of entity may some law of physics fails or may varies according to the system or solar system.

So how we can say that it cannot be possible.. Because of failure of law of physics. May different law governs different system

gaurav - India



The Laws of Physics seem to depend much on the sizes of objects being considered. At the very small sizes--such as sub-atomic sizes--a different set of rules apply. Likewise, at extremely large sizes and high speeds--such as with galaxies--other rules apply.

Both sets of rule average out when looking at the everyday sizes.

The atom can be considered like a solar system, but there are also many discrepancies in the comparison.

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Why do some fruits float in water?

Topic: Floating


January 5, 2015

Why some fruits floats on water,where as some not ?




If the non-water part of a fruit is less dense than water--meaning that it weighs less for the amount of volume--the fruit will float. However, some fruits have heavy pulp or large heavy seeds, which will make it more dense than water and thus sink to the bottom.

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Why are high clouds gasses at extremely low temperatures?

Topic: Snow


December 27, 2014

at a height of about 10000ft when temp is about -30 degree C, why are clouds still in gas state and not in solid state. what conditions will make it to solid state. kindly explain.


Kallan - Canada



With increasing altitude, the air pressure decreases. But also, the temperature required to change from gas to a solid decreases. See the illustration in Pressure and States of Matter and press the "water" button.

However, note that clouds at that height often are a mixture of water vapor and ice crystals.

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Metal with same density as liquid

Topic: Floating


November 16, 2014

A metal piece having density equal to density of fluid is placed to the liquid . the metal piece will? a) Sink to bottom b) fload c) partly immersed d) wholly immersed




If it has the same density as the liquid, the piece of metal be completely immersed in the liquid but will not sink to the bottom.

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Biscuit absorbs water and sinks

Topic: Density


November 11, 2014


I need to answer satisfactorily the following questions to my 6th Standard son. Please help me.

1.A biscuit first floats on water for a few seconds and then sinks.Why?

A related question though not falls under the topic of density of matters.

2.Why the biscuit becomes soft when put into water and breaks down?What happens to the intermolecular attraction (that keeps it compact) when sunk into water? In hotter water this process seems to be faster.What role does heat play here?

Abhijit - India



The biscuit first floats because its density is less than that of water. However, the biscuit soon absorbs water, such that the density of the soggy biscuit is then greater than water alone. Thus it sinks.

The biscuit is made of fibers that are separated by spaces that can contain water, once it slowly enters the spaces. But also, the water is absorbed in the fibers, loosening its intermolecular forces. Since water is a polar molecule, it can readily dissolve many materials.

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Why is mercury a liquid at room temperature?

Topic: Changing States of Matter


November 4, 2014

I have some questions...
1)why at room temperature copper is a solid,mercury is a liquid and oxygen is a gas?
2)what does it mean,i mean how strongly mercury atoms are attracted to each other compared to how strongly copper atoms are attracted to each other?
Can you explain me simply

Synthia - USA



Copper--like most metals--shares its valence or outer electrons with other copper atoms at room temperature. That keeps the atoms close together as a solid.

However, the valence electrons of mercury are more loosely attached and do not readily share with other mercury atoms. The reason the electrons behave this way is fairly complex. Mercury is pretty unique in this property.

Oxygen atoms have lower mass and do not attract each other as much at room temperature. Thus, they are spread apart as a gas.

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