How I check, test, and charge my AA and AAA batteries - and sift out defective ones

I've been a fan of Olight flashlights for many years. Now I'm a fan of its new pro-grade battery charger. Here's why.

I walked 3,000 steps with my Apple Watch, Google Pixel, and Oura Ring - this tracker was most accurate

Just how accurate is that smartwatch or smart ring? I tested three health trackers' step counters to find out.
Verywell Health

5 Ways Fitness Trackers Can Catch Early Signs of Health Issues as You Age

Some fitness trackers may detect signs of heart disease, sleep problems, and chronic stress. However, there are limitations and risks to consider.

New heart disease detector could save billions, improve care in Oklahoma

Acarix CEO Aamir Mahmood moved his medical tech company to Oklahoma City to improve heart health with a novel diagnostic tool.
C&EN

Data discovered in surprising places

In most people, carbon dioxide and hydrogen—not methane, Hall stresses—make up the bulk of farts. All that hydrogen comes from microbes breaking down beans, greens, and other gassy foods. “If you see ...