Ask the Van - Illinois Dept. of Physics

How to build a model atom.

Q:	I need to make a 3 dimensional model of an atom. Can you help with some ideas of constructing this. Thanks -Troy Reynolds Jenkins Middle School, Palatka, Florida USA

A:	Troy - Cool project! The basic structure of an atom is that it has little things called neutrons and protons that are stuck together in a ball (called a nucleus) in the middle, with electrons that spin around it very fast. Neutrons and protons are about the same size, and electrons are much much much smaller. You can use different colors to show which are neutrons, protons, or electrons. Neutral atoms have the same number of protons and electrons. If a neutral atom loses or gains some electrons it is called an ion. Atoms also tend to have similar numbers of neutrons and protons, though the trend is for heavier atoms to have have more neutrons than protons. A normal gold atom, for example, has 79 protons and 118 neutrons. An interesting fact is that although the "cloud" of electrons that surround the nucleus is much much much bigger than the nucleus itself, most of the mass of the atom (more than 99%) is due to the nucleus. The number of protons that an atom has is called its atomic number. For example, Hydrogen has one proton so its atomic number is 1. Some other elements are Helium (2), Lithium (3), Beryllium (4), Boron (5), Carbon (6), Nitrogen (7), and Oxygen (8). So far, scientists have discovered elements with atomic numbers of even more than 100! For more information on different elements, check out this Periodic Table. You can click on any element to find information about it, and the atomic numbers are listed on the table itself, so they're easy to find. As for what to build your atom out of, be creative! -Tamara (republished on 07/21/06)

Follow-Up #1

Q:	i am not sure how to do this project my teacher asked of the class. i am searching on the internet to find a step by step insructional paper on how to make a 3-D model of an atom. Do you have any kinds of resource like what i just explained? -Becky (age 13) crosby,tx

A:	We don’t have any special resources for that. More importantly, we have something strange to say about it. To the extent that we understand the small-scale world, including atoms, it has quantum-mechanical properties which are completely unlike any model you can build. For example, the electrons in an atom don’t really exist at some particular place at any time. Their state is smeared out around the atom’s nucleus. The usual sorts of models people like to display show the electrons as whizzing around like little planets, but that isn’t right. Mike W. (published on 09/19/07)

Follow-Up #2

Q:	There are two questions from students on how to create a 3-d model of an atom and no real answer for them. How frustrating for us. The second answer is telling us that it isn"t "real" so can"t be done, that is not an answer, the project doesn"t go away for us, we have to do it. Some suggestions like, styrofoam, clay, etc would of been appreciated. Thanks for nothing! -Ginny San Diego

A:	We’re trying here to both get across a little of what science has actually discovered and some of the methods used to find things out. Sometimes teachers give assignments that don’t fit well with those goals. Still, if you have to make models, you have to. Why not use a BB for the dense little nucleus at the center of the atom? Maybe a cotton ball would be usable to convey some of the ’cloudiness’ of the electrons, although nothing directly visible really shares the strange behavior of quantum-scale stuff. Mike W. (published on 12/13/07)

Follow-Up #3

Q:	Hi, I guess the assignment was turned in... I would suggest selecting any kind of object that is roughly sphere shaped from styrofoam balls to jelly beans. Use 3 colors. One color to represent protons, one for neutrons and a third for electrons (preferably much smaller than the p & n particles) Next, use the atomic number for the number of protons and electrons. Subtract the atomic number from the atomic weight to get the number of neutrons. Now glue the protons and neutrons together into a blob. That's the atomic nucleus. Then put the electrons in orbit around the nucleus. You could do this be strining them on a stiff wire wrapped in a circle or maybe draw a circle on a piece of poster board and glue the electrons to the circle, glue the nucleus to the middle of the paper. The atom should roughly resemble planets circling the sun. -Sue (age >25) Carlsbad, CA USA

A:	It's true that students could do that, and some of what it would convey about atoms would be true. However, at least as much would be false. For example, a planet circling the Sun is at a particular place and has a particular orbital velocity. The electrons in atoms are not in particular places and do not have particular orbital velocities, except when the orbital velocity is exactly zero. Then there is some indefinite velocity, but it's radial, i.e. toward and away from the nucleus. That's true of the electrons in hydrogen, helium, and some of the electrons in other elements. That's not a possibility for planetary motion. If the orbital velocity were too small (say zero, for example), the planet would fall into the Sun. If you were to imagine that the electrons were little classical particles in orbit, they would radiate electromagnetic waves, losing energy, and the atom would collapse in about a billionth of a second. That was a big puzzle before the discovery of the quantum laws that describe small things. We love to give simple explanations and pictures when it's possible, but when it's not maybe it's best just to tell students that to understand some mysteries they have to continue their educations. Mike W. (published on 04/14/08)

Follow-Up #4

Q:	how to make an atom .with the simple things. -huthashini (age 14) wgl.Ap.India

A:	Dear Huthashini, This is a very difficult question to answer. First of all it is a bit ambiguous. If you want to manufacture an atom, you can't go down to the store and buy the necessary materials. It would be extremely difficult, but in principle possible, to build a complex atom at a high energy accelerator although simple hydrogen-like atoms have been seen at the accelerator at CERN. If you mean by your question how to make a stick-and-ball model of an atom, that is something you can do; although resultant physical model would only vaguely resemble the actual atom. The reason is that at the atomic scale you have to take into account the quantum mechanical aspects of the individual particles, which behave not as billiard balls but as spread out wave functions. I hope I haven't confused you too much. Keep studying physics. LeeH (published on 06/28/08)

Follow-Up #5

Q:	Jeez, These are middle school students asking for help! They don't need to know schrodinger's model yet. Why are you confusing them more than they already are? I understand that they are building a "false" model, but their undertsnading of the atom will require a building and breakdown process. Don't you remember that YOU learned it this way too? -Jim Lotarski (age 37) St. Charles, IL USA

A:	Yeah, as you can see we heard similar complaints from some others. It's often a tough call to decide when it's ok to present a falsely simplified answer. We're happy to give Newtonian answers to mechanics questions where relativistic effects can be neglected. We're unwilling to give classical explanations for why some materials are magnetic since one literally cannot even start to say anything meaningful without quantum mechanics. The 'atom picture' questions fall in between. Here's our rationale for emphasizing the mystery. Almost all the students have seen the toy pictures of atoms with little dots whizzing around. We don't have anything to add to that, and we don't want to use a site which some people treat as a reference source to be saying that's accurate. The only real contribution we can make beyond what the kids are getting in school is to give a hint that there's something weirdly mysterious about the world at that level, and that maybe someday they can understand it. At any rate a BB and a cotton ball are not such exotic materials. And no, I didn't learn the Bohr atom, but maybe it is useful for some kids. Mike W. (published on 09/08/08)

Follow-Up #6

Q:	This isn't a question but as you can see I am putting it anyway. Mike W. you seem kind of stuck up. I don't know if its because you are a college proffeseor or if you are just tightly wound. I am in 8th grade and I need help making a "fake" atom model. You were absolutly no help at all. The only help I might have gotten from this site was from other people who have written in this question box. I hope this makes you see how not noce it is to confuse already confused 7th and/or 8th graders. So please next time a middle schooler askes a middle school question please give a middle school answer, or don't reply. Because it is absolutly no help to hear about how confusing an atom really is. Seriously. -Crystal (age 14) Norwalk, WI, US

A:	OK, we disagree. I think it's sort of fun that the world is a mixture of parts we understand and parts we don't understand. It gives something to look forward to. Mike W. (published on 03/25/09)

Follow-Up #7

Q:	As a teacher, I can say you have not been very helpful to the young people accessing your site for simple help to build a simple atom model!! Kids, three round objects, each a different colour. Two of the round items should be about the same size; the other should be smaller. For example, an apple, an orange and an MM. The larger two objects could be hung or connected together to form the nucleus(proton & neutron), and the small item could be hung, or glued on a dotted line to represent the electron. Hey presto! You've built a simple model of a Hydrogen atom - the smallest of the atoms. Well done!! Now check your Periodic Table to choose a larger atom you'd like to build for more of a challenge, and have fun eating the MM's you don't have to glue onto your model. :) -Ms. B (age old) Australia

A:	You're clearly in the majority on this. A few points in our defense: 1. The model you describe is not actually for hydrogen but for deuterium. If you ate the orange, you'd have a hydrogen model left. Since oranges are tasty and good for you, it would be a win-win move. 2. As we pointed out previously, models of this type are easy to picture but get almost all the basic features of an atom wrong. 3. If students were clamoring to build models of atoms, then teachers would have a good reason to try to supply something, even if it's pretty inaccurate. What we're objecting to is not the students but the teachers, who have decided to make students spend time learning something wrong. The world is full of interesting and challenging things that young students could learn right. Mike W. (published on 04/26/09)

Follow-Up #8

Q:	I fully appreciate that the model that is described has inaccuracies. But as far as teaching pupils things that are wrong I disagree. 1) Ideas often have to be simplified for pupils to have a chance at grasping them, jumping in woth oribtal theory just doesn't work. 2) Pupils understand the difference between a model and real life and a valuable skill for them to learn is evaluating. I would encourage any model to have it's strengths and weaknesses identified. 3) I don't know about in the states but in the UK it's the examing boards that dictate what students have to learn not the teachers. 4) This somple model of the atom explains many of the trends and patterns of Group 1,2,7 and 8 of the periodic table at the level they need to understand it. Unfortunately we're not all born with the ability to understand degree level work at birth. -Mrs B

A:	Thanks for the thoughtful remarks. Points (1) and (2) are hard to disagree with. On (3), here in the US, teachers usually have much more autonomy, except for on preparations for the No Child Left Behind tests, unfortunately those don't include science. On (4), I think the Bohr atom actually leaves the properties of the periodic table extremely mysterious. They don't seem to come in any natural way from the model, so complicated unnatural assumptions about 'shells' etc. are added. That's where it's different from, say, Newtonian physics, which is internally consistent and explanatory over a broad range of phenomena. Bohr leads to trouble right away. It's good at predicting spectral lines of hydrogen, but the students probably weren't worried about those to begin with. Mike W. (published on 06/06/09)

Follow-Up #9

Q:	As the mother of a middle school student who likes science, I agree with Mike regarding the futility of building models of atoms. Science teachers need to understand that today's middle school students are capable of understanding the general concept of electron clouds, and the impossibility of simultaeously fixing an electron's velocity and position, if it is explained in a straightforward manner as it is in Natalie Angier's popular science book, The Canon. Moreover, it is exactly the kind of bizarre and fascinating fare on which kids this age thrive! Clinging to a mini-solar system model of the atom post-Bohr misses the whole point of the radical changes in physics in the 20th century. It makes as much sense a having students construct geo-centric models of planetary motion post-Galileo. As long as average adult Americans shy away from the sciences, science teachers will not be held to a higher standard. And as long as science teachers are not held to a higher standard, their students will grow up to replenish the ranks of average adult Americans who shy away from the sciences... -Mary Connecticut USA

A:	Dear Mary, Thank you for your comments on this issue. We have received a variety of others not so favorable to our point of view. By the way I agree with your praise of Natalie Angier, a science writer for the New York Times. She tells it like it is, and has won a Pulitzer Prize for her reporting. LeeH (published on 06/11/09)

Follow-Up #10

Q:	I feel compelled to point out that the individual who indicated that US teachers have far more autonomy than was describe in a prior comment is flatly incorrect. This is particularly true in California where every single lesson must be bound to a Standard in the approved state curriculum. The standardized CAT-9 tests test directly from this standard, and in many school districts, teachers are being instructed to organize their lessons to address the specificity of the exam. In other words, they must teach to the test. This, of course, results in students lacking in critical and creative thinking ability once they leave the K-12 system. I think an assignment such as the one described is actually a terrific opportunity to promote both creativity and critical thinking precisely because it is not possible to construct such a model accurately. My 6th grader asked me to help her find a way to make a model of an atom. After reading about the complexity of such a task on this site, she is more determined than ever to do so. She wasn't happy with the cotton ball idea, because she doesn't think that it does a good enough job of representing the nebulous nature that Mike described. Can anyone think of another way to represent this? Maybe something that catches light randomly? -Mrs. E (age 45) Arcadia, CA, USA

A:	Thanks for the thoughtful letter. It's interesting to hear that the traditional autonomy of individual teachers here is gradually being reduced. It's also great that you and your daughter are using the problems with the assignment as a base to do something extra with it. As for ways of somehow somehow visually representing a bit of the elusive, random nature of atoms, perhaps one could add some little sparkles to a cotton ball. or to some clear gelatinous material. That way light would glint off different parts at different times, sort of randomly. It's not quantum, but fits in with the creative spirit with which your daughter is approaching the job- looking for suggestive visuals, not intended to be a real model. Mike W. (published on 09/01/09)

Follow-Up #11

Q:	Hey guys thanks for all the info though there were no direct answers to the "how to make a model" thing but you guys mike mrs b etc. gave me enough reference guides about atomic model like the atomic cloud or bohrs decision i can make my science project and it may end up in our science project exhibit THANKS A LOT =D -Ferdinand Laguna Philippines

A:	thanks for your note mike w (published on 09/12/09)

Follow-Up #12

Q:	My som came home with this exact project (make a 3d model of an atom) today. I am not a scientist or a science teacher but I have an idea about how to make an acceptable model. Elementary school teachers would most likely not be looking for the things mentioned in some of the replies here. Here is what we are doing - I purchased a clear plastic christmas ball that snaps in half. My son then filled this ornament with colored (only 2 colors) gumballs to represent the protons and the neutrons and snapped it back together. On the outside of the ornament is a hole that sticks out - this is where you would usually hang the ball - he made sure that he snapped it back together with half of the hole at opposite ends. He then looped craft wire to form a ring on which he put small beads to represent the electrons. I thnk it looks fine and I am sure his teacher will find it VERY acceptable! I just thought it might help someone else looking for a way to build a model atom for elementary school classes. -Heidi United States

A:	This is a very popular topic. Your model sounds very well designed for pleasing the teacher. It still would be nice to see something more fuzzy and spread-out, like a cotton ball, for the electrons, to start to suggest their actual behavior. On an atomic scale those little bead-like things literally wouldn't last a nanosecond. Mike W. (published on 09/23/09)

Follow-Up #13

Q:	Mike W you need to get a life or become a professional arguer. The mom with the beads puts out a practical and cheap model and you can't let it go. -Johnny Ramone (age 53) NYC USA

A:	Why would someone with 'a life' be answering questions from strangers? Mike W. (published on 10/14/09)

Follow-Up #14

Q:	Thank you for giving students something to think about - middle school is not too early to present the "falsity" of physical models. Kids should be aware of this early, and you've presented this clearly and accurately. My daughter has this assignment, and I'll insist she read your explanation and have a thorough understanding of what she is indeed building (and that it doesn't accurately represent an atom). KUDOS. -Teresa Gresham (age 39) Mapleton, IL, USA

A:	Teresa- Thanks for this kind note. It's been hard to convey to people that this site is about helping people think scientifically about the world, not about helping do school assignments. Just for entertainment purposes, I'll post some less favorable responses. Mike W. (published on 10/14/09)

Follow-Up #15

Q:	Mike W u dnt need to be sooooo technical.... u could dumb it down a little so us not so smart people could make a project to without getting overly confused about atoms when we are barley starting to learn and understand physics! i do apperciate ideas given by other question askers though... thx for that! -limecoke US

A:	ok (published on 10/14/09)

Follow-Up #16

Q:	What an interesting discussion! I'm amazed at how emphatic some people about their points of view. As a middle school science teacher, I love this project for the purpose of presenting inaccurate models. As a few people have mentioned already, middle school is a GREAT time to get students thinking critically about scientific concepts. Just as the Bohr model was historically used as a stepping stone to our better understanding of atomic structure, I think it's an essential part of a student's understanding of this structure. Yet despite how much we might like the simplicity of this model, it's important for students to take that next step. Even after completing an assignment of constructing a 3-D Bohr model, middle school students are usually curious enough about the world around them to be fascinated by the more current understanding we have. A discussion about how this could be modeled in 3-D would be very interesting. This is where I like to share computer-generated models with my students. Not only will students be able to better grasp the idea of the electron cloud but these models generally also include motion which can help students to see the more erratic movement of electrons within this cloud. Thanks to everyone who has contributed to this conversation! It has certainly informed me as a teacher about the sometimes unspoken repercussions of assignments I give. Mike--you'd be amazed at how little academic freedom is given to public school teachers these days. We do our best to keep things interesting and meaningful for students but in many cases the concept of educational "standards" has taken on a new meaning of what/how/why things are taught in today's classrooms. -Mr. P (age 23) Miami, FL

A:	Mr. P. - Thanks for keeping up the good work in a tough situation. Have you seen this set of computer simulations? http://www.falstad.com/qmatom/ It is amazing to somebody who went through the public school system many decades ago that the structure has changed so much. It's even a big change since my kids went through. Mike W. (published on 10/21/09)

Follow-Up #17

Q:	Not so much a question, but I think the reason a lot of people have problems with your answer is that they think the Bohr model is basically right, and there are just some esoteric tweaks necessary to make it compatible with quantum mechanics. To them, it seems like you're criticizing a child's model of the solar system because he's drawn the planets' orbits as circles, rather than ellipses. They don't get that the Bohr model is in fact almost totally wrong, and in fact badly misleading, since it implies that subatomic particles behave just like macroscopic objects, only on a very small scale. Of course, it could be just the usual case of people getting upset when scientists tell them things that are hard to understand. I would have assumed that someone asking this website this question would want a more knowledgeable answer than "glue little colored balls and sticks together" - it doesn't take a PhD physicist to tell kids to do that. -Eric (age 37) Los Angeles, CA, USA

A:	Thanks, Mike W. (published on 11/04/09)

Follow-Up #18

Q:	I am a chemistry teacher. I hold a B.S. in biochemistry, an M.S. in nutritional sciences, and an M.A.T. in science education. I am mortified and livid every day at the substandard product my middle and elementary school teachers send me. I want kids to know HOW to think, not WHAT to think. I am sick to death of trying to reteach students good ideas and thoughts based on the lies about atoms they learn in middle school. This is akin to being a biology teacher. Why don't we teach kids how good it is to put leeches on their bodies, or about black bile, phlegm, blood, and green bile, and then send them to high school to learn how things really work? It's easy to be lazy and teach kids lies. I am glad they don't do that in my district. Oh, and by the way, I taught college at an R1 university too (actually two of them, both land grant schools.) I am mortified at the misconceptions our science students have there as well. Don't do our kids a disservice and lie to them. Scaffold them properly. Examine evidence. Do some experiments. Show them Rutherford. Do math (kids can do ratios). But don't lie to them. They are the ones going to Mars.....don't they deserve better? -Scott (age 41) Chemistry Teacher, USA

A:	Thanks for joining the discussion. Mike W. (published on 11/04/09)

Follow-Up #19

Q:	My 6th grade son came home with this assignment. Some here have said this is a lame assignment. However, you have to begin somewhere. There is only so much you can do at this level. At least it gets them thinking and using their imaginations a bit. I think most of us forget what it is like to be that age. We were no Einsteins then. There is almost no experimentation or hands on stuff in school right now. Every moment is scripted. I used to volunteer to do math games every other week with my kids classes, now they don't have time to spend an hour every two weeks. State requirements dictate every minute. I went to high school in the 70s and learned about the atom the "old" way, but have become educated in the real world way from my own curiosity. I don't leave my kids' educations up to the schools. Be active in their and supplement what they learn at school. -John

A:	One thing I've definitely learned from this whole question is that there's a major unmet need for some sort of forum in which teachers, students, and parents can thrash out issues in education. We're happy to accidentally supply that for this particular issue. Maybe we can encourage our friends in the Ed School to do something more systematic. Mike W. (published on 11/09/09)

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