Questions and Answers

Questions are an important part of the scientific process and, over the years, hundres of people have sent their questions to us. Listed below are some of the most common, and most interesting, questions visitors to our site have asked. A special thanks to all of the staff members who have taken the time to help answer these questions. Your efforts are greatly appreciated!

Atoms, Elements and Molecules

Since Jefferson Lab is a nuclear physics research facility, it isn't surprising that we're often asked questions about atoms. We've selected the most common questions from the main archive and have listed them here for your convenience.

Basic Information

What is an atom? What are atoms made of?

What is an element? How many elements are there?

What is the difference between atoms and elements?

What is the difference between a compound and a molecule?

What is a mixture?

Atomic Structure

How do I find the number of protons, electrons and neutrons that are in an atom of an element?

How many electrons fit in each shell around an atom?

How do I read an electron configuration table?

How do I make a model of an atom?

What does the element krypton look like?


Who discovered the element gold, silver, copper, neon, etc...?

Complete Question Archive

Atoms and Matter

What is an atom? What are atoms made of?

How do I make a model of an atom?

What is one example of indirect evidence that scientists use to study an atom?

What is an element? How many elements are there?

What is the difference between atoms and elements?

What is the simplest way of explaining what atoms, elements, compounds and mixtures are?

What is a mixture?

What is the difference between a compound and a molecule?

I am not clear on what a molecule is. If water is a molecule, is it also a compound because the hydrogen and oxygen have been chemically combined? If so...

What is the biggest atom? The smallest atom?

How do atoms form?

Does gravity affect atoms?

Can you crush atoms?

What are the components of an atom? How much does each atom weigh?

Is there an atom that does not have neutrons?

What is the modern view of the structure of the atom? How are the protons different from neutrons? What are the differences between protons and electrons?

What kind of charge does a proton have? And what kind of charge does a neutron have?

Why do protons and neutrons stay together in the nucleus?

How many times bigger is a proton than an electron?

Why are electrons so far away from the nucleus of an atom?

How many electrons fit in each shell around an atom?

How are electrons placed in shells around the nucleus?

How do I read an electron configuration table?

What holds an electron revolving around the nucleus? Why don't they just go zooming around everywhere?

What keeps the electrons revolving around the nucleus of an atom?

How much of an atom is empty space?

If atoms are made up mostly of "empty space," what is in that empty space?

If atoms are 99.999999999999% empty space then why don't things pass right through them?

If all physical things are made of atoms, then why do different physical things have different physical properties? Like why is wood hard and rubber soft?

How fast do electrons move?

What do we use to measure mass?

Is matter everywhere?

If everything around us is matter, what about germs?

How do you prove air is matter?

Why is matter not being created at the present time, nor being destroyed?

Why don't atoms weigh anything?

What are the exact relative masses of protons, neutrons and electrons?

If different types of quarks have different masses, then why are protons and neutrons said to have the same mass, when they have different compositions of quarks?

What is plasma?

How do you know plasma is real if you can't see it?

What is the smallest particle of matter known?

Could there be anything smaller inside of an electron or inside of a neutron or a proton?

How many quarks are in a proton? How many quarks are in a neutron?

What kinds of quarks are protons and neutrons made of? What was the old name for the Top and Bottom quark?

What is the charge of an up quark and the charge of a down quark? How many quarks make up a proton and a neutron?

Are quarks confineable for study?

Is vacuum matter? What are ten things that are not matter?

What is a vacuum? Is it matter?

Elements and the Periodic Table

Why is hydrogen's atomic number 1?

Will scientists ever find smaller elements or is hydrogen the smallest possible?

Who discovered the elements?

When studying elements I noticed that there is a boiling point and melting point. What are they?

What are the freezing and melting points of krypton?

What does the element krypton look like?

Is krypton dangerous?

Why aren't Chlorine-35 and Chlorine-37 two different elements?

What makes hassium an element if it has no uses except basic scientific research?

If you have 11 protons and 12 neutrons this is an atom of what element?

What's the difference between hydrogen, nitrogen, oxygen, neon, copper, gold and magnesium?

Does sodium have any isotopes? Is it radioactive?

Anything with an atomic number greater than 92 (Uranium), is called transuranic. These elements are manmade, but is there a difference...

What atoms make up sugar? After sugar is melted over heat, what is the black substance called?

Is carbon found in all organic and inorganic matter?

In the chemical equation for methane gas why is there more hydrogen than carbon?

How do you separate tungsten from its ore?

What would you get if you combined one atom each from all the elements in the periodic table?

Electricity and Magnetism

What type of charge is produced when an electric field separates positive and negative charges?

What is an electric current?

How do you explain electrical resistance?

Do you know what an electromagnet is?

I am creating an electromagnet for my school's science fair project. Does the shape of the iron core make a difference?

Why is it (in detail) that the more coils you add to an electromagnet, the stronger its magnetic field is?

Which jobs use electromagnets?

Why is a non-permanent, but long lasting, magnet called a permanent magnet?

Permanent magnets can lose their magnetism if they are dropped or banged on enough to bump their domains out of alignment. Can you turn something back...

What happens when a magnet is cut in two? Does the strength of an electromagnet depend on the number of turns of wire? If you have two magnets...

Does the size of a magnet make it stronger? How are magnets made? How does the shape of a magnet effect it's magnetic field?

Why does rubbing plastic and wool together create electricity?

History of Science

Where does the word atom come from and who first used this word?

Are Democritus' theories of atoms still relevant today?

How do people really know that atoms exist even though they can't see them?

If there is no way in the world to see an atom, then how do we know that the atom is made of protons, electrons, neutrons, the nucleus and the electron cloud?

When was the nucleus discovered?

How do the elements on the element table get their chemical symbols?

Why do the electron shells begin being named with K, L, M, N, and not with A, B, C?

Was "beauty" a quark name they used in the past?

Who invented magnets?

What did Thomas Jefferson do as a scientist?

Can you explain why the United States uses Fahrenheit instead of Celsius?

Scientific Math

If the energy could be directly converted to matter, how long would it take a person on a bicycle-type generator to create a single atom?

Is there a way to tell how many atoms are in a certain object?

How many atoms are in the human head?

How many atoms are in the human body?

How many atoms are there in the world?

How many atoms would it take to create a ton?

Could you please explain density? What is it? What is the concept of D = M over V?

How do I find the number of protons, electrons and neutrons that are in an atom of an element?

How do you determine how many protons, neutrons, and electrons are in an atom?

What would happen to the atomic number and the electric charge of an atom if two neutrons escaped the nucleus?

What are vector quantities and how do they work?

Radiation and Radioactivity

How is radioactivity measured - in quantity?

How does the radioactivity of an atom affect the body?

If radioactivity is so dangerous why do we use it to destroy cancers, and could the treatment cause more damage?

What are alpha rays? How are they produced?

What is an alpha particle?

Is it possible for an element to emit more than one kind of radiation?

How many neutrons can you add to an atom without it getting unbalanced?

Are nitrogen, arsenic, and tantalum radioactive?

How long is the life span of an atom?

Someone told me that Cherenkov radiation is analogous to breaking the sound barrier. In the latter, an object travels faster than the speed of sound...

Do radioactive things glow in the dark?


If energy is formed by a generator, how does the generator form the energy?

Do rotating magnets create energy? Where can I find more information on this subject?

What is the fastest type of energy?

Lasers and Light

How do lasers work?

My science fair project is on how prisms separate light. What is light made of?

Can you use light to push light?

Is possible to make a real light saber like in the Star Wars movies?

Jefferson Lab

What's used to steer Jefferson Lab's electron beam?

How much money does it cost a year to run Jefferson Lab? Do you get funds from an entrepreneurship?

Why are the Halls in bio-dome shapes?

Why did it take so long to build Jefferson Lab? Why was Jefferson Lab built in Newport News?

What would happen if a part of the accelerator or one of the magnets were to break or come off? Would the electrons come out of the machine...

How big around is the tunnel at Jefferson Lab and what do you do in it?

Scientific Instruments and Experimentation

How does a scientist work?

What does a physicist do?

What is an accelerator operator?

What process do you go through before you start the experiments? Do you use a hypothesis?

What is an accelerator?

Does an atom smasher really smash atoms?

Where and how do you get your electrons for your accelerator? What kind of machine or process did they use to split the first atom all those years ago...

Why do you need high energy to look at or observe quarks? Since the accelerator at your facility is linear and can't always get as much energy...

How did you make the detectors work in Halls A, B and C?

How can you tell if a new type of element has been created, especially if only a few atoms of it were created and if they only existed for a millisecond?

What kind of equipment do you work on?

How did you make so much neat stuff?

Miscellaneous Questions

What is air made of?

Does baking soda lower water temperature? If so, why?

Do liquids freeze at the same temperature? Why doesn't oil freeze?

In space we feel weightlessness because the earth's gravity has less effect on us. Why do we not see the effect of the gravitational force between the various objects...

What is a lattice vibration?

How cold is liquid nitrogen?

Is there anything colder than liquid nitrogen?

If you jumped into a pool of liquid oxygen, would your body instantly crystallize?

What's the melting point of steel?

What is a material with a freezing point above 0 degrees Celsius?

What is a meniscus?

How can I explain the Quantum/Wave theory to my class?

What two minerals is the sun made out of?