Stress is a word used by engineers to describe both the external force applied to a material and the internal strength required to resist the pressure. [See Lloyd John Ogilive, Making Stress Work for You: Ten Proven Principles, with Built in Study Guide (Waco, TX: Word, 1985), 25-26.] Such combined stresses will cause the material to change both size and shape. An example of this can be seen in a metal like iron. It has a yield point at which outside pressure increases the density of the metal. This would make it stronger. When this strain exceeds its load bearing capacity, what is known as a “failure point” causes the metal to break. This is what happens when a blacksmith heats and hammers a horseshoe. He is not only shaping the metal, but he is increasing its strength.
- Stress is external pressure that causes physical, mental or emotional strain.
- Stress is internal resistance in response to outside pressure.
- Stress is negative pressure that results in distress, danger or destruction.
- Stress is positive pressure that results in motivation and movement: “The stress of having to support a family caused the young man to seek a better job.”