Two teams of inventive youth compete to help out a champion bike racer from Maine on today’s episode of “Design Squad,” airing at 5 p.m. on the stations of the Maine Public Broadcasting Network.

On the PBS Kids program “Design Squad,” the purpose of which is to promote engineering and design challenges, two teams seek to create their own version of various objects.

On today’s episodes, the Green Team and the Purple Team design and engineer gravity bikes for Gravity Sports International champion Tom Whalen, a 19-year-old Brownfield native.

Gravity bikers race downhill on bikes with no cranks or pedals, reaching speeds of up to 90 mph.

It’s fun to watch the two teams start with ordinary bikes and then transform those into a form of transportation that they’ve never used before. Host Nate Ball helps shepherd them through the design and fabrication stages, following the specs for gravity bikes.

But it’s not enough for the bikes to look right. Next comes testing, and then the big showdown, with the bike that crosses the finish line first deciding the winning team.

It’s encouraging that a program such as “Design Squad” exists to help provide some much-needed promotion of engineering among American kids, while making it seem enjoyable as well.