You can use your smartphone to get pretty much anything delivered directly to your door almost immediately. The hardest part is the process of trying to work out if you should tip and if so, doing the quick math before you get to the door. And, you know well that you should tip about 15-20% at restaurants, but do the same rules apply to delivery drivers?

The co-founder of Grubhub, Matt Maloney, pretty much set the standard for tipping delivery people in a Facebook post. He’s a strong supporter of tipping, and Grubhub’s website suggests a $5 or a 20% tip. Maloney also said this number should go up if you order during, say, a snowstorm.

However, most other delivery services say on their websites that tipping is not required. Some services, like Door Dash, do suggest no tip on their checkout window. Many, like Amazon Prime Now, allow customers to change their tip amount after their delivery has been received to reflect the quality of service. These companies help customers save money but delivery drivers are upset. They deal with bad weather, heavy traffic, extreme tiredness, and more, all for a $1 tip. Many feel that if you’d tip your pizza boy or girl, you should tip your delivery driver.

The Emily Post Institute (EPI)’s official suggestion falls in line with Maloney’s: “10-15% of the bill, or $2-5 for pizza delivery depending on the size of the order and difficulty of delivery.”

Just like servers in a restaurant, delivery drivers almost always rely on your tips for their income. Tipping is a long-standing cultural tradition in America. So, until drones (无人机) can deliver hot dogs straight to your door, it’s best to tip the people riding through the city at all hours to bring you hot fresh food.

Parker Stewart, a 16-year-old from Sayre School, a college preparatory school in the United States, knew last year that he wanted his independent study on the environment to have a broad impact on the community. In order to "reduce the carbon footprint," Stewart planned to produce enough solar energy to power the school's science labs. Now his plan is set to happen. The installation of 30 solar panels is scheduled for late January.

As he began his research on solar energy, he discovered a useful phone app. By entering an address, he could find out how much sunlight the location receives each day. Based on how much sunlight it receives, Stewart found that his school building was the desired position.

At the suggestion of his science teacher, Debbie Wheeler, Parker first performed an energy audit（测算）of the science lab to see how much energy a typical lab uses per day. Then, he started his research, contacting a local installer of solar panels, Synergy Home, to do the job.

Parker lacked money for launching the project, so he convinced Sayre's head of school to fund him after explaining the benefits of solar power for the school and community. Since Sayre provided the initial seed money to provide supplies and the purchase of one panel, the project has grown to include a total of 30 panels. They are expected to generate enough energy to run all four of the science labs on campus.

"It feels like a dream to think that an idea I had resulted from my AP Environmental class would have this kind of impact," said Stewart, expressing gratitude for Wheeler's help.

Wheeler said the success of the project was due to Parker's efforts and willingness to follow through on the project from start to finish.

“I've had other students talk about environmental initiatives on campus, but Parker had the persistence to make it happen," she said.

Rosie Colucci’s medical history is filled with a series of thunderstruck numbers: 3 rare and life-threatening diseases—an inoperable brain tumor(肿瘤), neurofibromatosis and hydrocephalus—countless medications, including six types of chemotherapy(化疗); 14 brain surgeries, mainly to implant catheters to keep fluid from gathering on her brain, a result of the hydrocephalus; 16 other surgeries and 230 tests; 405 clinic visits; 1,486 doses of chemotherapy; 71 nights in the hospital; 33 emergency room visits; and 11 stays in the ICU.

Another number: Rosie’s age—14. An official cancer diagnosis came when she was little. After a decade of being sick, the teenager would much rather focus on some different numbers.

Take 60,000—that’s how many new toys, games and blankets she’s helped get into the hands of hospitalized kids. She’s also raised hundreds of thousands of dollars for pediatric cancer research. Rosie increases her toy giveaways around the holidays but gives them out year round.

It didn’t sit well with her as a kid learning to share that so many people gave her stuffed animals and toys, while other kids hospitalized with equally serious diseases weren’t seeing the same gifts.

Rosie works tirelessly on Rosie’s Toy Box, a charitable organization she came up with, which now is on the path toward becoming a registered nonprofit, drawing hundreds of donated toys for hospitalized kids.

“I wanted to de-emphasize the expecting of gifts and asking for gifts, and I just wanted to give her a sense of giving rather than always receiving,” Cathy Reichl, her mother, said, “I hope it’s something that stays with her as she grows, and I think it will be—the realization that not everyone has what you have, some people have struggles with their health and we could just use something to brighten their days.”