Psychology professor Laurie Santos teaches Yale's most popular class ever. One in four Yale students have enrolled in Psychology and the Good Life since Yale began offering it last year.

It's all about how to be happy. Built on psychological science, Santos offers students a playbook in how to "practice" happiness in your daily life. She then adapted it for an online Coursera class open to the public. Anyone can now take Yale's 10-week course, now titled The Science of Well-Being for free, taught by Santos herself.

In a year, 225,000 people have already taken it. Business Insider contributor Justin Maiman is one. Five weeks in, he says he's a happiness convert. Here's what Maiman says he's learned in the course thus far.

Happiness homework? Yes, please.

Understanding the science behind what makes people happy is a start. There are countless research studies about where happiness comes from, or what you can do to boost your happiness.

The real value in taking this happiness course, though, Maiman says, is what you learn from doing the homework: "daily exercises geared toward changing your habits--recognizing and then dropping bad ones while developing new good habits."

All the exercises are backed by science, and are proven to work in helping people live happier lives. Don't have 10 weeks of your time to invest in the course? Here are a few of the homework assignments that will help you incorporate the science of happiness into your everyday life.

Assignment 1: Take a strengths assessment test (15 minutes)

One of the first homework assignments is to take the VIA Survey of Character Strengths. It takes about 15 minutes. Developed by happiness psychologists, the survey is intended to help you zero in on your best qualities.

Then, you're supposed to embrace those strengths and try to use them more in your everyday life--and especially at work.

"In my case, I looked for simple ways to use fairness, humor, and love of learning throughout my day," Maiman writes.

Assignment 2: Stop and smell the roses (30 seconds)

Another assignment is to look for one out-of-the-ordinary moment each day. When that moment happens, you should take a few seconds to notice it, appreciate it, and savor it.

This could be a silly few seconds giggling with the kids. A kind interaction with a barista. Or simply noticing a beautiful flower on a walk. Take note of that special moment, and try to tell someone else about it later.

"Looking for these moments has boosted my sense of awe at the world around me," says Maiman.

Assignment 3: Keep a gratitude journal (5 minutes)

Students are asked to keep a journal in which they write down five things they're happy for every day. This practice can supercharge your happiness. Gratitude activates parts of your brain related to the release of dopamine. It significantly raises your level of optimism. Researchers have also found that writing down what you're thankful for can help with everything from improved sleep to positive behavioral change.

Can't commit to doing this daily? Try once a week to start. You might find the benefits so beneficial that you can begin journaling more regularly.

Assignment 4: Buy someone else a surprise coffee (2 minutes)

One homework assignment is to look for opportunities to commit random acts of kindness. Maiman began buying friends, colleagues, and even strangers coffee.

Money can buy happiness--if you spend it on the right things. This includes prioritizing experiences over things and paying people to do tasks that buy you time.

It also includes spending money on other people to make their day--even if it's a small gift. Making other people happy, in turn, makes us happy. "It's kind of like getting a little click of cocaine every single time you do a nice thing for another person," Santos explained.

Eager for more homework assignments scientifically proven to make you happy? Check out the Science of Well-Being class to find out for yourself. ?