Chemical engineers in Peru are learning about *Mathematica* from a new blog. Dr. Manuel Cerpa, a chemical engineering professor at the National University of Engineering in Lima, Peru, writes *Aplicando Mathematica a la Ingeniería Química*, a Spanish-language blog about using *Mathematica* in chemical engineering. Each post includes an interactive Computable Document Format (CDF) app that demonstrates a particular concept or problem.

## Blogging with CDF

Cerpa began the blog to raise awareness of *Mathematica* in Peru. He first discovered *Mathematica* nine years ago, in a scientific paper in which it was used to solve a complex thermodynamic model. Since then, he has been using it in his research to solve phenomenological problems in chemical engineering.

He thinks it's important that more people in his field know about using *Mathematica* for solving common cases in mass and heat transfer, fluid flow, chemical kinetics, thermodynamics, and mass balance. Many problems in chemical engineering need explicit algebraic solutions. In addition, ODEs in many problems can be solved with good interactive graphics.

With CDF, he can show results graphically and interact with them using the controls, saving time because he doesn't have to recalculate the model for each set of parameters.

Using CDF on his blog lets him share interactive examples with people who don't have *Mathematica*. Because anyone can download the free *CDF Player* and interact with the CDFs he made, he reaches a wider audience.

## CDF in the Classroom

Cerpa uses some of the CDFs on his blog in his classes as well. He started using *Mathematica* for teaching master of science students six months ago.

"I believe that *Mathematica* is primary software for any student in the university," he says.

With *Mathematica*'s interactive capabilities, students work with live mathematical models and dynamic graphics.

"It's very important because many problems have static graphical solutions (nomograms) and they don't help to understand the effects in the variation of key parameters," Cerpa says.

Using CDF files lets him spend more class time explaining the effects of changing parameters. That helps the students discover new relationships and learn the underlying physical or chemical phenomena rather than how to solve a mathematical model. Students experimenting for themselves learn more than they would from a book and become better prepared to solve other cases or real industrial problems with *Mathematica*.

"I believe that students understand better and faster if a physical or chemical problem is solved graphically than if it's algebraically," Cerpa says. "In addition, with the controllers, the students interact with the problem, and they can learn the effects of a change."