References

Reference How do personal air purifiers work — and can they really improve the quality of the air we breathe?

Reference How to test the air quality in your home, according to experts.

Sharks are formidable fish, having survived multiple mass extinction over hundreds of millions of years. But how much do you know about these misunderstood creatures? Take our quiz to find out.

BUYING GUIDE The best cameras for wildlife photography have impeccably accurate autofocus, a fast burst rate and sharp, detailed images — we've rounded up the best models.

BUYING GUIDE The best astrophotography cameras require excellent low-light capabilities — check out our favorite models to watch for this Black Friday.

BUYING GUIDE The best star projectors bring the wonders of the cosmos into your home — find the best models here so you're ready for Amazon Prime Day.

The best binoculars for kids should be lightweight, compact, and easy to handle — explore top picks before Amazon Prime Day arrives next week.

How many of the 160 named volcanoes in the U.S. and territories do you know? If you live in Alaska you have a big advantage.

Unlock the night sky with the best binoculars for stargazing designed to capture stars, planets, and distant galaxies — our top picks for Black Friday Week.

Find the best binoculars for wildlife, stargazing, tracking athletes, or plane spotting — check out top picks ahead of Amazon Prime Big Deals Day next week.

The best telescopes offer an unparalleled view of the cosmos, and we've gathered our favorites just in time for Amazon Prime Big Deals Day.

The Periodic Table, first created by Dmitri Mendeleev, organizes all of the known elements in an informative array.

BUYING GUIDE These are the best running watches in every category, from Garmin Fenix 7 to Apple Watch Series 8 and Coros Pace 2.

Buying Guide Looking to check out macOS? Here are the best MacBooks for students you can buy right now.

These are the best Garmin watches you can buy in every category, from Fenix 7 and Forerunner 265 to Venu 2 Plus.

These are the best budget fitness trackers you can buy in every category, from Fitbit Inspire 3 and Garmin Vivosmart 5 to Amazfit Bip 3 Pro.

Buying Guide These are the best fitness trackers you can buy in every category, from Apple Watch Series 8 and Garmin Fenix 7 to Amazfit Balance.

BUYING GUIDE These are the best treadmills you can buy in every category, from NordicTrack x22i and Mobvoi Home Treadmill to Peloton Tread.

Buying Guide These are the best rowing machines you can buy in every category, from Concept2 RowErg and Ergatta Rower to Hydrow Wave.

Buying Guide These are the best electric toothbrushes for kids, from Oral B Kids and Philips Sonicare for Kids to AutoBrush Sonic Pro.