A number of districts in the West and Midwest are cutting school once a week to save both money and teacher morale.

On Mondays, high school senior Bridget Stoddard isn’t at school — she’s at a Starbucks. Working.

Stoddard isn’t playing hooky. Her Colorado school district, 27J, moved to a four-day week last year. Initially, the change was disorienting for the 17-year-old Brighton High School student, and she worried she wouldn’t be able to adjust to a college schedule. One year later, Stoddard uses the day to stack up work shifts and prepare for the upcoming week.

Stoddard’s district is among an increasing number of districts in Western and Midwestern states that are adopting a four-day school week. Most of the districts are rural and small, but 27J, located on the outskirts of the Denver metro area, became the largest district in the U.S. and the first in a major metropolitan area to transition — joining more than 60 percent of Colorado districts with shorter weeks but longer days to meet the threshold for hours. Only 20 districts in 21 states had four-day school weeks in 2016, according to the National Education Association — a number that has since climbed to 560 districts across 25 states.

Martin Drewes and Martina Findling developed an innovative water filtration system in Germany. The trick is making it scalable in Kenya.

As a German soldier in Bosnia two decades ago, Martin Drewes remembers fretting over children subsisting on “a little bit” of bottled water, while the rest was too dirty to drink.

“It’s always been at the back of my mind,” the idea that this life-sustaining resource is taken for granted, the 43-year-old mechanical engineer says in his spartan office on a former Soviet base that’s now Magdeburg-Stendal University of Applied Science. After all, in his native Saxony-Anhalt, fresh H2O is everywhere — so plentiful that a bigger worry is the Elbe River inundating the lush, green countryside.

Years later, after an unsuccessful attempt to create a water wheel-powered electric generator for use in disaster-hit communities in the developing world, he had an idea. While his pontoon-mounted dynamo tied to a riverbank couldn’t do much more than charge a mobile phone, he thought the water wheel turning it might be repurposed for something more meaningful: making unpotable water drinkable.

This grueling six-month course teaches you how to identify every plant and animal under the African sun.

It’s Day 3 of Track and Sign week and a trio of Land Cruisers grumbles toward today’s classroom. Breaking up into small groups, the khaki-clad students try to identify the dozen or so animal tracks their trainers have circled in the sunbaked sandy track. “That must be a leopard,” says one at what looks like the paw print of a domestic cat on steroids. “No, no,” whispers another. “Look at the insets behind the lobes: It’s a lion cub.” A couple of hundred yards away, a lone elephant scratches against a marula tree.

The students are a third of the way through the six-month Professional Field Guide Course offered by Bushwise Field Guides near Hoedspruit in South Africa. The course — which is split between a thatch-roofed classroom and a 27,000-hectare private game reserve that’s home to all of the Big 5 (buffalo, elephant, leopard, lion and rhinoceros) — covers everything from identifying raptors to learning how to handle a .375 rifle when an angry (cardboard cutout of a) buffalo is bearing down on you. Students who pass the final exam are qualified to work as game rangers, revealing the wonders of the African bush from a Cruiser with a rifle on the dash. For those wanting a foot in the door, Bushwise can arrange a six-month unpaid internship at a lodge.