India, Oct. 7 -- Imagine that the body of your car was cultivated on a farm. At the 1941 Dearborn Days, the yearly local festival, Henry Ford had an opportunity to provide his own version. The Henry Ford Museum says he displayed a plastic car there on August 13, 1941. The vehicle became known as the soybean car.

The vehicle used a tubular steel chassis with 14 plastic panels and weighed 2,000 pounds, or 1,000 pounds less than a conventional steel car. Ford had other motivations too. He wanted a product that could connect agriculture with industry, use plastic to reduce reliance on scarce metals, and potentially make the car safer in a rollover.

Despite its famous name, the exact materials used in the plastic panels remain uncertain beca...