Question

[1]
In 1964, anticipation of a gasoline shortage prompted the DuPont company to search for a new, lightweight fiber to replace the steel wire in automobile tires. Chemist Stephanie Kwolek was assigned to the project. She began analyzing long chains of molecules called polyamides, hoping to find a fiber that was both strong and lightweight.

[2]
Initially, her supervisors were skeptical, believing the cloudy mixture would damage the delicate spinneret machine. However, Kwolek persisted, and when the solution was finally spun into fibers, the results were astonishing. The new material, later named Kevlar, was five times stronger than steel on an equal-weight basis.

[3]
The breakthrough occurred when Kwolek created a liquid crystalline solution that was unusually thin and cloudy, unlike the thick, clear mixtures typically produced in her lab. Instead of discarding this seemingly defective batch, she decided to test its properties by spinning it into fiber.

[4]
Today, Kevlar is used in everything from bulletproof vests and racing sails to bicycle tires and spacecraft. Kwolek's discovery, which began as a search for a tire component, ultimately revolutionized personal safety and materials science.

For the sake of the logic and cohesion of this essay, where should Paragraph 3 be placed?