According to the NUS website, Critical Thinking is a collection of overlapping mental activities, namely, intuiting, clarifying, reflecting, connecting, inferring, judging, etc.

The emphasis of a Chemical Engineering curriculum is to prepare the students for career Process Engineering. Process Engineering is a collection of operations - mixing, reaction, separation, heating, cooling, increasing pressure, deceasing pressure, etc.

The students are introduced to concepts, for example, diffusion, dispersion, driving force (for mass, heat and momentum transfer), friction, interface, phase equilibrium, etc. There are governing physical & chemical principles/laws like conservation of mass, conservation of energy, ideal gas law, Raoult's law, Fick's law, Fourier's law, Newtons laws (of motion, of cooling), to name a few. These laws allow quantitative description of the concepts, which are combined with knowledge of mathematics and intelligent assumptions to achieve process quantification, as illustrated in the diagram below. Intelligent assumptions allow a highly complex real phenomena to be reduced to essential basics and, therefore, to keep the mathematics within tractable limits.

It is expected that a good process engineer should be able to conduct performance analysis and trouble shooting through first principles understanding of cause-effect relationship, be able to contribute in process improvement and new design, and make educated judgment in selecting from alternatives.

Process Engineering involves making assumptions, interpretation and analysis of data, making connection between concepts to explain observations, and selecting from alternatives. Ability to connect among all these issues is the other name of critical thinking in process engineering.

Contributed by S Farooq, Department of Chemical & Biomolecular Engineering ().