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I have a quest to explain a physical, chemical theory to kids of age 8-12.

The topic is "Ionization". We all understand from early experiments of Physics and Chemistry (the Millikan oil drop experiment) how a neutral atom in gas becomes a charged atom where radiation knocking the electrons out of the neutral atom.

Here's the story line I came up with. Can you guys please help me to make this a success and correct the wrong impressions, expressions and examples in the narrative? I am open for any better examples.


There's a high-class (=high voltage) shopping mall area (=radio activity area metaphorically) in the country I am living right now. One particular shopping mall called ION. If you enter that shopping mall, you will shop and get excited (=charged) and spend your pocket money (=losing electrons) by the temptation (=radiation) from fancy shoppers around. Shopping means getting exposed to radiation.

Some shoppers are highly influential (=alpha rays with +2 charge) and there's a high tendency you will spend money (=lose electrons). e.g. Movie theater. You get excited even looking at it from far.

Some other shoppers are less influential (=beta rays with -1 charge). e.g. Junk food, a piece of cake you like to eat. You have to go near to see the food and then spend your money on it. The excitement of eating the food lasts for shorter period compared to the movie you watched. So the impact from movie is higher. You will talk about it in school for a week or two. Unlike the food you had and forgotten by the next meal.

The last type of shoppers are least influential (=gamma with 0 charge). e.g. Manga shop. You don't find it as exciting as watching a moving or eating favourite food. But you may go there as a matter of need (for a manga copy) or peer-pressure from your friends to buy manga and spend your money. You are kinda forced to get excited (=charged) to spend a buck on it.

So it's quite dangerous for you (=neutral atom) to enter or go near a shopping area (= radiation area) where you will be losing your money and get excited for nothing...

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    $\begingroup$ I do not have a very good feeling about this approach. Anyone that can make sense of your shopping mall explanation surely is capable of understanding ionization itself. $\endgroup$ – iad22agp Aug 17 '14 at 18:57
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    $\begingroup$ If you enter that shopping mall, you will shop and get charged (=excited) ... should be ... excited (=charged) ... $\endgroup$ – LDC3 Aug 19 '14 at 4:45
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    $\begingroup$ Feel free to edit :) much appreciated. And our intention is to make a positive impact on kids to be more conversant with science. So a simple, catchy, memorable and fun example would make that happens... @LDC3 there's another meaning to charge. e.g. charge, a fee. So I need to find a better way to indicate that excitement is like charging a battery. $\endgroup$ – bonCodigo Aug 19 '14 at 5:16
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    $\begingroup$ It might just be best to use the Bohr model of the atom and explain that the electrons and protons cancel out the charges in a neutral atom. When an electron is removed or added, the charge changes. Metaphor will only complicate things. The Bohr model isn't correct, but for illustrating basic concepts like ions to children the simpler the better. Once the concept of ions is understood, you can move on to ionization through radiation by incoming particles stripping away or adding electrons. $\endgroup$ – user137 Aug 19 '14 at 14:10
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    $\begingroup$ I am sorry that I am not able to contribute more meaningfully to this effort. I think the best approach to teaching kids about chemistry is to let them experience the behavior of matter itself. Without that experience, a concept like charge or ion really does not mean anything. You could use a magnet to affect the behavior of electrons in a fluorescent tube. Or observe a salt dissolving or crystallizing out of solution (salts are made of positive and negative ions). Or run a current of electricity through a salt and see a metal be plated on one electrode. $\endgroup$ – iad22agp Aug 19 '14 at 14:31
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I think the key concepts that are explainable at this age level are:

  1. Atoms are made of protons, neutrons, and electrons
  2. Protons have positive charge, electrons have negative charge, neutrons have no charge
  3. Opposite charges attract
  4. Atoms can gain or lose electrons, but not protons or neutrons
  5. Atoms hold onto their electrons more or less tightly depending on which atom it is (you won't be able to really explain why, but you could just show them a periodic table and explain that non-metals (the right side) like electrons more than metals (the left side))
  6. Atoms can "steal" electrons from each other
  7. Electrons can be "knocked off" of atoms by high-energy photons (light or EM radiation)

The difficulty with explaining these things by analogy to regular-life experiences is that there is no regular-life experience that captures the whole picture. This means you are limited to activity-type demonstrations, videos/pictures, or analogies for specific pieces of the puzzle.

I would recommend a mixture of all three approaches. Kids like hands-on stuff, so maybe you could explain the basic concepts with very simple analogies, then do an activity where the kids are given "electrons" (tennis balls, maybe) and are assigned to be metals or non-metals. Then you could have them give each other electrons and count charges as they go. If you had containers that could hold 8 electrons, you could even represent valence shells and the octet rule - metals could start with two or three electrons, non-metals with 5, 6, or 7, and the metals would need to empty their shells while the non-metals would need to fill them.

This would demonstrate a very important concept that is hard to teach in the abstract: Electrons don't disappear.

Since you are also interested in teaching about ionization by radiation, you could assign each student a number representing their ability to "hold on" to an electron. Here is where you might be able to use a shopping-type analogy - only instead of students giving up electrons as money, they would give them up in exchange for money. In this case, the money represents the energy, and you would be giving them the energy (money) needed to remove (sell) an electron. Atoms that charged a higher "price" (require more energy) would wind up with more money at the end of the exercise.

There are many variations on these ideas that you could use, but I think anything that covered the seven points I mentioned above while simultaneously developing an intuitive understanding that energy and electrons are conserved could be called successful.

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    $\begingroup$ @downvoter : I don't see a reason to downvote this answer. I was taught about ions by real life analogy and I misunderstood most of the things. Better understand nothing than to misunderstand things. :) $\endgroup$ – ashu Aug 22 '14 at 4:04
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    $\begingroup$ +1 I am taking a good look at your concept @thomij :) And appreciated all the you guys here making the contribution for our next generation little scientists =) $\endgroup$ – bonCodigo Aug 23 '14 at 2:11
  • $\begingroup$ @bonCodigo SE has always strived to help the next generation scientists :) $\endgroup$ – Pritt says Reinstate Monica Jul 24 '17 at 3:13
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thomij has given an excellent answer. I'd like to add a few more. He told:

  1. Atoms can "steal" electrons from each other

You could do an arrangement to explain why atoms need to steal electrons. Get some marbles and a four-bladed boomerang like this (or any other medium-sized radially symmetric object):


(source: dxcdn.com)

Now, balance the boomerang on it's center. Add marbles to the corners of the 3 blades. The kids can see that the boomerang will remain balanced if all the four corners are placed with marbles. This is a real-life analogy to the Octet-Rule, although real atoms need 8 for balancing while our analogy was with 4.

I hope this analogy is worthwhile.

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  • $\begingroup$ Pritt, cheers! This was 3 years ago ^^ kids (not mine) have grown up and I moved ahead a nanometer or so. $\endgroup$ – bonCodigo Aug 18 '17 at 4:10
  • $\begingroup$ @bonCodigo Oops I totally forgot to see the date. $\endgroup$ – Pritt says Reinstate Monica Aug 18 '17 at 6:10

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