Background: Nanoparticles are structures up to 100 nm in size. Estimation of their
size is usually determined by assessing of images obtained from scanning electron microscopy
(SEM) and/or transmission electron microscopy (TEM) techniques. Studies on the effect of visual
cognition on the analysis of these types of images are limited.
Objective: The aim of the research was to determine whether students’ visual cognition influences
the identification, analysis, and measurement of nanoparticle size through SEM and TEM
imaging using ImageJ software.
Methods: The visual cognition of each participant was evaluated by recognizing individual nanoparticles
and measuring their diameter using ImageJ software. Finally, the Kruskal Wallis test
was performed for statistical analysis.
Results: Participants applied or not four main identification criteria in order to identify individual
nanoparticles: shape, high contrast, defined edges, and presence/absence of agglomerates,
being “shape” the predominant parameter taken into account to measure the diameter using ImageJ.
Average diameters, number of measured nanoparticles, and standard errors of measurements
varied between groups in all analyzed images, evidencing the influence of visual cognition
on the measurements.
Conclusion: We conclude that there is an effect of visual cognition in the identification of nanoparticles
and their diameter estimation. The user’s training, background, experience, perspective,
and operational conditions of SEM/TEM play a fundamental role in estimating the size of
nanoparticles measured in microphotographs using ImageJ.