"Hund's Rule states that in order for electrons to be in a state of lowest energy, no electron pairing takes place until each orbital in the sublevel contains one electron.
If the empty seats on a bus represent the available orbitals in a given sublevel, one would normally observe that strangers would tend to sit in separate seats until all the seats contain one person, then begin pairing up.
A stranger who came and sat on your seat even though other empty seats were available, might put you into an anxious or 'excited' state since you would be wishing the person would move to an unoccupied seat."
Previously posted at scienceanalogies.com by retired science teacher Murray Hart – original source: Goh, Ngoh Khang; Chia, Lian Sai; and Tan, Daniel. Some Analogies for Teaching Atomic Structure at the High School Level Journal of Chemical Education September 1994, 71(9), p.733
A stranger who sits next to you on the bus when there are double seats free behaves like an electron that disobeys one of Hund's rules
Many examples of science analogies are listed in 'Creative comparisons: Making science familiar through language. An illustrative catalogue of figurative comparisons and analogies for science concepts'. Free Download.
"When a beam of low frequency, low energy light is directed onto a metal surface, it will reflect off with no effect upon the metal. If many light sources of the same frequency are used, there is still no effect on the metal. An analogy would be that if you shoot at a person in a suit of armour using either a single BB gun or many BB guns at once, the person inside the armor will not be affected.
If light of higher frequency and energy from only a single source is used, then this greater amount of energy may be absorbed and cause electrons to be promoted and ejected. Similarly, if the BB gun is replaced by a more powerful rifle, then it would only take one shot to pierce the armour and hurt the person inside."
Previously posted at scienceanalogies.com by retired science teacher Murray Hart – original source: McCullough, Thomas Simple Analogies in General Chemistry Journal of Chemical Education July 1992, 69(7), 543.
Many examples of science analogies are listed in 'Creative comparisons: Making science familiar through language. An illustrative catalogue of figurative comparisons and analogies for science concepts'. Free Download.
"According to the Quantum Theory, an electromagnetic wave guides a flow of energy which is transported along the wave in bundles (photons) of size hf. A simplified view of the situation would be to say that if a wave was represented by a group of people marching in a line, the photons would be analogous to the backpack each person was wearing, and each of which contained a particular amount of material. This analogy could be extended to say that older, more energetic adults would carry a greater load in their backpacks than would children."
Source: Murray Hart, retired science teacher, previously posted at scienceanalogies.com
Many examples of science analogies are listed in 'Creative comparisons: Making science familiar through language. An illustrative catalogue of figurative comparisons and analogies for science concepts'. Free Download.
"When a power boat is cruising on a lake, the wave which it produces has its greatest amplitude right at the boat, and the amplitude decreases as the distance from the boat increases. Thus you could locate the most probable location of the boat by analyzing the amplitude and energy of its associated water wave.
This is analogous to the wave mechanical model which visualises the atom as a positive nucleus surrounded by vibrating electron waves. The Schrödinger Wave Equation describes the amplitude and other characteristics of the waves which are associated with the moving electrons, and thus it also is able to describe the energy and location of the orbiting electrons."
Source: Murray Hart, retired science teacher, previously posted at scienceanalogies.com
Many examples of science analogies are listed in 'Creative comparisons: Making science familiar through language. An illustrative catalogue of figurative comparisons and analogies for science concepts'. Free Download.
"Sometimes electrons are described as being small particles of matter. At other times when we describe the organisation and behavior of electrons, we treat them as wave patterns.
Someone who had never seen a television would report seeing recognizable images of people, buildings, etc. when watching the screen from across the room. However, a similar observer, if placed with their eye right up against the screen, would report seeing dots of varying colors and brightness. Both descriptions of the screen are correct; the perspective of the viewer determines which properties are observed at that moment."
Previously posted at scienceanalogies.com by retired science teacher Murray Hart – original source: Licata, Kenneth P. Chemistry Is Like a … Science Teacher 1988, 55(8), p.42
Many examples of science analogies are listed in 'Creative comparisons: Making science familiar through language. An illustrative catalogue of figurative comparisons and analogies for science concepts'. Free Download.
An example of an analogy drawing upon a scientific idea:
Figure 7.6 Mapping an analogy between types of bonding and types of learning.
"The left-hand part of the figure shows a triangle of ideal learning types. One apex of the triangle is labelled rote learning – where a person learns some isolated fact without connecting it to any other ideas. This is contrasted with meaningful learning where what is learnt is integrated into a complex structure of ideas (represented by the side of the triangle opposite the point of rote learning). There are two ideal types of learning here, where learning is simply absorbed into a pattern of ideas it fits perfectly (sometimes called assimilation) as opposed to where what is learnt has to be made to fit, to be accommodated, by a major restructuring of prior thinking.
The point of the triangle is to suggest that actual learning is nearly always somewhat linked to prior learning (not entirely rote, but not integrated perfectly with other potentially relevant ideas) and that new learning generally modifies prior thinking somewhat, although seldom revolutionises it. So, the ideal types, the apices, are useful referents, but real learning is normally located somewhere in the triangle. The bonding triangle maps onto the learning triangle; that there are ideal types of bonding map onto the suggestion that there are ideal types of learning; and the general rule that bonding is characterised somewhere within the bonding triangle maps on to how learning generally falls somewhere within the 'learning triangle'. This learning triangle may then be seen as analogous to the bonding triangle familiar to chemists. We might therefore be able to conjecture useful features of learning from our knowledge of bonding. Meaningful learning is often like polar bonding – at neither of the extremes of perfectly fitting, nor completely disrupting, prior learning.
Any such device is capable of being misunderstood unless clearly explained. For example, any reader who spent time trying to work out why rote learning mapped specifically onto metallic bonding (rather than perhaps covalent bonding) would be over-interpreting this particular analogy."
Many examples of science analogies are listed in 'Creative comparisons: Making science familiar through language. An illustrative catalogue of figurative comparisons and analogies for science concepts'. Free Download.
An example of an analogy drawing upon scientific ideas:
"It is also likely that just how a teaching approach is best applied (or indeed sometimes customised to local conditions) will be quite different in diverse teaching and learning contexts. Teaching is not the kind of activity that can sensibly be planned and prescribed centrally – it always needs to respond to the specific curriculum, the specific course, and the specific learners. Perhaps this is not so different from a chemical process like crystallisation or fractional distillation where certain general principles always apply, yet the precise procedures followed will be modified according to the mass of the sample concerned and the specific reagents involved."
Many examples of science analogies are listed in 'Creative comparisons: Making science familiar through language. An illustrative catalogue of figurative comparisons and analogies for science concepts'. Free Download.
A complex analogy for student learning drawing upon chemical ideas (and intended for an audience already familiar with the chemistry).
"We might consider that often there is a considerable 'barrier' to learners acquiring new, abstract and unfamiliar ideas. Once a person has acquired a new concept and integrated into their wider knowledge based (connected into relevant local mental 'concepts maps') and consolidated it through a regular application, it becomes a stable feature of their 'conceptual ecology'. However, the 'transition state', that is whilst the new idea still seems strange, is not yet strongly associated with other ideas, and cannot yet be confidently applied, will be highly unstable. This is reflected in Figure 7.1 which uses the analogy of a reaction profile for the progress of a student's shift in conceptual understanding.
It is as if the transition state is a highly labile and weakly bonded complex that can decompose by any number of pathways unless the teacher carefully guides the process to the desired product. We might see this as the pedagogic equivalent, perhaps, of making sure the pH, temperature, solvent, etc., are carefully chosen to encourage the formation of a preferred product. Extending my analogy, this is reflected in Figure 7.2.
Sometimes, however, we can help things along by using a 'catalyst', so to speak, in presenting a comparison that helps a learner form a notion which, whilst not quite yet what we are working towards, is an accessible 'intermediate' conception on the way to the curriculumtarget knowledge.
…This may be a lot easier for the learner as the barrier to forming this somewhat more familiar notion is a lot lower than acquiring the new abstract idea. This is clearly a useful thing to do. . . but a good intermediate conception may be so stable, that if we are not careful the reaction does not proceed any further. …
This is reflected in Figure 7.3. It is almost as if the teacher feels that all the hard work is done, and the learner's 'excited' mental state is expected to 'relax' to an intended ground state almost of its own accord, allowing the teacher to move on; whereas within the learner's conceptual ecology, this final stage may be more like a kind of 'forbidden' transition which will only occur given sufficient time (as in phosphorescence where light continues to be emitted for some time after a luminescent material was irradiated by an ultraviolet source)."
Figure 7.1 Conceptual learning may require overcoming a large 'barrier'.
Figure 7.2 Unless learning is well consolidated, conceptual change can lead to various outcomes.
Figure 7.3 Teaching analogies and the like may support the ready formation of inter- mediate conceptions that seem convincing to learners in their own right.
Many examples of science analogies are listed in 'Creative comparisons: Making science familiar through language. An illustrative catalogue of figurative comparisons and analogies for science concepts'. Free Download.
"Scientists generally operate with the assumption that there is, in principle, a single coherent account of the world (the universe, everything). We might consider this a metaphysical commitment underpinning science as an activity. Science would not make much sense without this assumption. Scientists can be considered to be working towards such a unitary worldview (even if each individual scientist is only concerned with a few pieces of the overall puzzle), although they may differ considerably in the extent to which they believe humans may eventually be capable of revealing the full picture. So, if ideas are being proposed in two areas of science which both seem fruitful and productive at the moment, but which also seem inconsistent, then the typical scientist would assume that either it will be found that the inconsistency is only apparent, or that at least one of the ideas has a flaw.
An authentic science education reflects the authentic nature of science and this includes this notion that it works towards a coherent picture of the world. This means biology cannot adopt a notion of protein structure that is at odds with what is taught in chemistry, and chemistry cannot use an energy concept inconsistent with the energy concept applied in physics. The links between different concept areas, within and beyond chemistry, should be emphasised in teaching as that is an important aspect of science: we do not adopt concepts or principles which seem to work well in one local sub-field without regard to their being consistent with the rest of science (or if we do, we do so as a stop-gap measure till 'the parole board' has considered the matter).
I know from my own work with learners that this 'obvious' feature of science is not always apparent to them and that sometimes they seem to treat different science courses as akin to a range of different sports, each with its own concepts and rules. For some learners, expecting physics to apply to chemistry is something akin to having to worry about being given out 'leg-before-wicket' when playing soccer when you should be focusing on keeping onside. An authentic science education emphasises how ideas from one area of science often support or build on those from others, and in any case are considered to reflect a limited number of underlying core principles."
"…I talked to a learner in one of my chemistry classes who was struggling making sense of energy levels in atoms. As I also taught her physics, I was aware that she had only a few days earlier undertaken a physics experiment measuring the diffraction of light from a sodium lamp, in order to measure the frequency of emission lines. From my teacher's perspective, this was relevant, and should have helped her understand – but the learner seemed horrified that whilst she was already struggling to make sense of the chemistry, I wanted to complicate matters further by asking her to think about something she had happily done in a different curriculum subject … (In terms of the analogy used [above], she did not consider it helped her when she thought she was playing soccer, to be warned she needs to avoid being given out 'leg before wicket'.)"
Many examples of science analogies are listed in 'Creative comparisons: Making science familiar through language. An illustrative catalogue of figurative comparisons and analogies for science concepts'. Free Download.
"Concept Development in Individuals and in Science
For Vygotsky, the formal concepts we learn give us the means to deliberate on, and to analyse, our spontaneous concepts; and our spontaneous concepts provide the experiential grounding for relating to, and understanding, formal concepts we are introduced to. Conceptual development involves a kind of dialectical interaction between the two types (although, again, we should not assume this all occurs consciously). Vygotsky used a metaphor of the two types of conceptsgrowing towards each other. We might see an analogy here with the dialectic at the heart of science: observations of the natural world motivate theoretical speculations, which motivate new experiments and observations, which inform the development of the theory, which informs new empirical work (and the construction of novel techniques and instruments for doing that work), which. . . ."
Many examples of science analogies are listed in 'Creative comparisons: Making science familiar through language. An illustrative catalogue of figurative comparisons and analogies for science concepts'. Free Download.
According to the Bohr Model, electrons can only exist in particular energy levels around the nucleus. This is like a stick shift on an automobile … it only works when it is in 1st gear, 2nd gear, etc., – and not at any in between position."
Many examples of science analogies are listed in 'Creative comparisons: Making science familiar through language. An illustrative catalogue of figurative comparisons and analogies for science concepts'. Free Download.
"One of the main postulates of the Bohr Model of the atom is that electrons can only exist in certain stable energy levels. It is analogous to saying that when you stand on a ladder you have a certain amount of potential energy at each rung position, and you can not stand at any in between position or have any in between amount of energy. If you do try to stand at a position in between two rungs, you will always automatically slide down to a lower rung and a correspondingly lower energy position."
Source: Murray Hart, retired science teacher, previously posted at scienceanalogies.com
Many examples of science analogies are listed in 'Creative comparisons: Making science familiar through language. An illustrative catalogue of figurative comparisons and analogies for science concepts'. Free Download.
