When it comes to science, South Washington County Schools Superintendent Keith Jacobus said recently, he knows just enough "to be dangerous."

In truth, the former biology teacher has maintained a lifelong fascination with brain science.

This month, he will share some of that expertise when he hosts three community conversations on adolescent brain development — the latest in a series of "Parent University" sessions that he's run since taking over as superintendent in 2012.

Jacobus is striking while the topic's hot.

In March, the University of Minnesota released a study about teens and sleep, basing some of its research on developments in the South Washington County School District. Test scores have risen in the district's high schools since officials decided in 2009 to push back high school start times from 7:35 to 8:35 a.m.

The idea that a student's performance would improve if he or she got eight hours of sleep seems obvious enough.

But it is the science behind it that explains why an 8:35 a.m. start is so important, researchers say.

As children grow older, they have a later release of the sleep hormone melatonin, Jacobus said, and don't begin feeling drowsy until about 11 p.m. For teens, that means that even if they went to bed early hoping to get eight hours of sleep before a 7:35 a.m. start, they'd have difficulty drifting off because their bodies aren't ready for it.

Jacobus said parents should be aware of research, too, showing that the blue light of electronic devices "tends to stave off that sleep pressure that you have." He planned to suggest that they discourage their children from using devices for an hour before bedtime.

Jacobus said that he couldn't cite a specific study supporting an hour of device-free activity — as opposed to, say, 30 minutes. But, he added, "I think the general rule of thumb is to stay away from something that stimulates the brain."

People wishing to learn more can attend one of three sessions: April 28 from 6:30 to 8 p.m. at Grey Cloud Elementary in Cottage Grove; April 30 from 9 to 10:30 a.m. at the District Service Center in Cottage Grove, and April 30 from 6:30 to 8 p.m. at Royal Oaks Elementary in Woodbury. □