1. The development of the Standard Model of elementary particles is one of the most significant achievements in physics in the 20th century. While refinements of this description of the subatomic world continue to be made, an understanding of the basic components and structure of this model serves as a foundation for appreciating the new discoveries in particle physics that frequently occur. One way to organize the elements of the standard model is in a display like that shown in Figure 12.23. Another way is to use a concept map. Examine Figure 12.23 closely and, if necessary, reread the material leading up to it. Then, using the principles of concept mapping that we have employed so often in past chapters, try to construct a map that captures the essential features and relationships embodied in the standard model of particle physics. When you have completed your map, exchange it for one that a classmate has prepared.

Critically examine your friend’s map. Does it include the most important concepts contained in the Standard Model? Does it properly exhibit/explain the relationships between the various elements of this model in a manner consistent with Figure 12.23 and the material introduced in the chapter? What are the strengths and weaknesses of your colleague’s map? Discuss these issues with the person with whom you exchanged maps and together try to come to create a better CM display and, in the process, a stronger understanding of the Standard Model.

Figure 12.23: Standard Model of elementary particles.

2. The following list of key words or items relating to the field of cosmology:
Redshift .......................................... cosmological constant
Dark energy ................................... dark matter
WIMPs ...........................................   inflationary model
Big Bang .......................................    flatness problem
False vacuum state ......................   expanding universe
Hubble law ...................................    critical density
Type Ia ..........................................     supernova

In the spirit of previous Mapping It Out! exercises, organize these concepts into a meaningful hierarchy according to their relative importance, significance or scope, linking them as appropriate by words or short phrases that reflect the relationship between/among the various items, to form a concept map for this portion. Does the structure of your map manifest a particular “flow,” for example, large → small; early → late; simple → complex; etc. If not, do you see any opportunities to re-organize your map to produce another model that might have such thematic trends, thereby making it easier to understand or master the information?