Differentiation is the process (or the result of that process) by which cells and/or tissues undergo a progressive specialization of form or function.

The forces acting on a surface can be separated into components perpendicular (normal) to and tangential to the surface. The normal force causes a normal stress and the tangential force is responsible for a tangential, or shear, stress acting on the surface. Shear forces cause contiguous parts of a structure or liquid to slide relative to each other.

Electrophoresis is the separation of a substance based on the electrical charge of the molecule and its motion in an applied electric field.

An exception to the standard combustion process is hypergolic combustion. In this situation, a fuel and an oxidizer spontaneously react on contact without the need for an ignition stimulus. The jets used to maintain and change the Shuttle's orientation when in orbit are powered by hypergolic reactions.

The creation and use of mathematical models is a key element of science, engineering, and technology. Modeling begins with identifying the physical and chemical phenomena involved in an experiment. Associated mathematical equations such as equations of motion are then identified. These governing equations are solved in order to predict important aspects of the experiment behavior, using appropriate values of experiment parameters such as density, composition, temperature, and pressure. Simple mathematical models can be solved by hand, while more complex experiments are generally modeled using sophisticated algorithms on high speed computers.

In microgravity research, scientists use modeling in preparation for flight experiments and in analysis of the results. Models and experiment procedures are fine-tuned based on comparisons between model predictions and the results of ground-based microgravity experiments (for example, drop facilities and parabolic aircraft flights). This preliminary work allows researchers to best take advantage of space flight opportunities.