Changing ideas about the periodic table of elements and students' alternative concepts of isotopes and allotropes

The Periodic Table of Elements (PTE) is one of the organizing principles in chemistry. Originally it was a list of elements (as substances). Later, the PTE developed into a list of atoms of the elements. However, isotopes and allotropes are difficult to integrate into the PTE. Therefore, difficulties in understanding these terms can be expected. The investigation set off to study secondary school students' concepts of isotopes and allotropes and how the concepts are linked to the PTE. Three specific research questions were addressed: (a) How do secondary school students describe the relationship between fundamental particles constituting an atom? (b) How do they conceive isotopes? and (c) What are students' concepts of graphite and diamond? Multiple choice items were given to 3074 senior high school students. In addition, six interviews were conducted with senior high school students. The data analysis revealed students' alternative concepts, which distinguished between standard atoms and atoms of isotopes. Standard atoms contain neutrons and protons in equal numbers and are more stable. The atomic masses are expressed as integers. Moreover, students considered graphite and diamond as isotopes. The analysis of the results shows that students actively tried to make sense of what they had experienced. © 2003 Wiley Periodicals, Inc. J Res Sci Teach 40: 257–277, 2003     

Differences in Established Joint Attention in Hearing-Hearing and Hearing-Deaf Mother-Child Dyads: Associations With Social Competence,Settings, and Tasks

The authors examined relations among observed joint attention, maternal report of child’s social competence, setting (home vs. laboratory), task (unstructured vs. semi-structured), and dyad type [hearing mother–hearing child (n = 55, M_age = 25.8 months) vs. hearing mother–deaf child (n = 27, M_age = 26.9 months)]. Hearing child dyads scored higher on joint attention during unstructured tasks, especially in their home environment. Hearing child dyads displayed similar joint attention to deaf toddler dyads when they engaged in a semi-structured task, but higher on these measures during unstructured free play. Unlike hearing children, joint attention was differentially related to social competence in deaf children, with relatively higher versus lower social competence depending on relatively high versus low observed joint attention, respectively.     

Adult-like odor preferences and aversions in three-year-old children

Previous studies of young children have failed to demonstrate adult-like odor preferences in children less than 5 years old. To test whether these results may have been due to inappropriate methods or to stimulus sets that were too limited in range to capture discriminations, a forced-choice procedure embedded in a simple game was used to contrast 3-year-olds' (n = 16) and adults' (n = 17) hedonic reactions to 9 odorants. Subjects indicated liking an odor by pointing to one puppet and disliking an odor by pointing to another puppet. Analyses revealed essentially the same pattern of preferences in both groups. In general, the odorant was a much better predictor of its hedonic quality than was the age of the subject. However, children and adults did differ in their ratings of some odors, and response patterns indicated that children may be more sensitive than adults to some odorants (e.g., the steroid androstenone). These data indicate that the predominant view that adult-like odor preferences and aversions do not exist until between 5 and 7 years of age must be reevaluated.     

Improving media production design skills through the use of a design analysis checklist

Conclusion As they would apply to each production, there are no “right” answers to most of the questions on the Design Analysis Checklist. On many of the items, research and marketing findings and the wisdom gained by successful media designers over a long period of time could perhaps sometimes tell the novice designer which decision would be best in a particular instance. But each production is far too complex and unique as a total entity to be able to make flat general statements as to what is proper in terms of design. Rather than trying to tell you what is right in media design, this analytical exercise is aimed at helping you to identify some of the design elements where decisions must be made—not whatdecision to make. Through experience and learning from experienced, successful designers, you will in time be better able to make the right decisions for each production. Reading some of the sources listed at the end of this article can help you in this regard. While the Checklist probed for answers dealing with dozens of design elements, do not lose sight of the fact that the basic story or message is the most important element. Without a well-organized and vital story or message presented in an interesting manner, it matters little about the other design elements. On the other hand, if your story or message is strong, well-organized, and interesting, these dozens of other elements can be used to improve the production in places where it is appropriate.