The red tip on these matches contains phosphorus, which ignites when in contact with oxygen.
The elements that make up each column of the periodic table share a set of common traits. Here, a chemist describes group 15 and the crucial role phosphorus, in particular, plays in cancer.
International forces advancing toward Boxer soldiers outside the Imperial Palace in Beijing, China, during the Boxer Rebellion.
Library of Congress
When is math not just math? Political conflicts have led to new study-abroad initiatives, the creation of a world-class university, the migration of mathematicians and serious educational reforms.
The 40-foot Peace Cross dedicated to World War I soldiers.
AP Photo/Kevin Wolf
A case regarding the constitutional validity of a cross shaped war memorial, is pending before the Supreme Court. An expert explains why these symbols have different meanings.
Trump has signed a law aimed at curbing sex trafficking.
AP Photo/Evan Vucci
Governments should heed the expertise of the grassroots nonprofits that witness this scourge firsthand.
Hotels and motels along major highways are common spots for sex trafficking.
New England Patriots CEO Robert Kraft's criminal charges in a suspected sex trafficking case draw new attention to this illicit underground economy.
Rev. Wyatt Tee Walker during a news interview in 2004.
AP Photo/Frank Franklin II
Rev. Walker worked closely with King and would be the one to bring King's Letter from Birmingham Jail to public attention. He was the only one who could understand King's handwriting.
The statue of Jefferson Davis, president of the Confederate States of America, stands in Richmond, Va.
Virginia's stark political contradictions, reflecting centuries of racism and a new liberal majority, were on display when a blackface image was found recently on the governor's old yearbook page.
Random arrangement of the elements.
2019 is the International Year of the Periodic Table. The person who typically gets credit for its creation is Dimitri Mendeleev. But there were many more chemists who should be recognized.
Spraying salt onto roads is a safety measure.
When it snows, it pours – but why do municipalities treat the roads with salt? A chemist explains how salt affects water and ice.
Elk on the move in Yellowstone National Park.
What is the best way to conserve US national parks in a climate-altered future? One answer is connecting parks and other public lands, so plants and animals can shift their ranges.
Staying on track with exercise goals can be hard without a plan to deal with stressors that get in the way.
Behavior change is very hard. Try as we might to keep those New Year's resolutions, many have given up by this time. Here are some ways to keep going and stay on track, from a counseling psychologist.
Burmese fishermen raise their hands as they are asked who among them wants to go home. Human trafficking sometimes occurs in the seafood industry.
AP Photo/Dita Alangkara
Estimates of modern slavery vary widely, whether they try to pin down numbers in the U.S., across the globe or just in certain industries.
Pop metaphorical ‘brain bubbles’ by grounding your brain in the here and now.
Decades of work with lab rats lead to suggestions on how to stay grounded in the here and now, with benefits for brain health.
Do you know this downy woodpecker?
By looking closely at traits like wing feathers and spot patterns, a computer scientist trained an algorithm to recognize individual woodpeckers.
An early voter in Norwalk, California.
The odds favor a big year for Democrats, but the extent of their gains is still in doubt.
The Floating Mosque of Palu that survived after the earthquake.
AP Photo/Tatan Syuflana
A majority of the over 24 mosques spread over Palu were damaged in the tsunami. Two of them survived, though one of them is gradually sinking.
Those mesmerized by NASA’s accomplishments and ambitions wanted so much more out of the reticent Armstrong.
After the first moon landing, the feelings that propelled a unified national mission quickly dissipated. Could Armstrong have played a bigger role in galvanizing the public for future projects?
A bridge in Palu, Central Sulawesi, Indonesia, was destroyed in the recent earthquake and tsunami.
AP Photo/Aaron Favila
The devastation of the recent earthquake and tsunami might be most visible in Palu, the capital city of Central Sulawesi. But the province’s rural areas could ultimately suffer the most.
A prime mystery.
A famous mathematician claims to have cracked a longstanding problem involving prime numbers. But his results still need to be verified.
Dead from the My Lai massacre.
Peers Inquiry, v.3/Ron Haeberle
If Americans remember My Lai, they likely know that something awful happened there. On this 50th anniversary, it is worth recalling the grotesque details, in the hope of preventing a future My Lai.