Chemistry Reference
In-Depth Information
The results of their study showed that, through the ERP data, the high-achieving
students did in fact perform mental rotation more often in identifying 2D chemical
structural formulas than the low-achieving students since the amplitude of rotation-
related negativity potentials is larger for high-achieving students than for
low-achieving students. That is to say, the low-achieving students used similar
cognitive processing to identify 2D figures and chemical structural formulas. To
sum up, Huang and Liu (
2012
) summarized that the reason low-achieving students
used less mental rotation to identify 2D chemical structural formulas than high-
achieving students is because the low-achieving students did not realize that the 2D
chemical structural formulas were projections of 3D chemical structural formulas;
hence, they used the mental rotation which they used in identifying 2D figures to
identify 2D chemical structural formulas. However, mental rotation is an inappro-
priate strategy in this case. The evidence was also supported by the students
'
interview data.
The results of this study not only reflected the different strategies which high-
and low-achieving students adopt in identifying chemical structural formulas but
also revealed the students
different beliefs regarding the nature of the representa-
tions of chemical structural formulas. Many previous studies had indicated that
assisting students to understand chemical structural formulas well should be
established in the virtual and real models and representations of chemical structural
formulas (Gilbert,
2008
; Mathewson,
1999
; Mo
`
,
2009
;N´˜ez-Pe˜a & Aznar-
Casanova,
2009
; Seddon & Eniaiyeju,
1986
; Stevens, Delgado, & Krajcik,
2010
;
Wu, Krajcik, & Soloway,
2001
). However, in Huang and Liu
'
s study, they men-
tioned that many low-achieving students rotate the 2D chemical structural formulas
(Fig.
20b
) as 2D figures because they believe that a chemical bond is a real physical
bond in the representation of 2D chemical structural formulas (Fig.
20a
), and so
they rotate the chemical structural formulas in the same way as 2D figures in daily
life.
In the practice of chemical education, many teachers and textbooks use ball-and-
stick models to demonstrate chemical structural formulas (Frailich, Kesner, &
Hofstein,
2009
; Huang & Liu,
2012
; Stevens et al.,
2010
), but if the limitations of
the analogies of these models are not emphasized, the students might believe that
the chemical bond is a real physical entity and use daily life experience to rotate the
'
Fig. 20
An example of 2D figures and 2D chemical structural formulas (Huang & Liu,
2012
)
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