The kilogram was defined back in 1795 in the context of water — “one liter of pure water at a temperature of four degrees Celsius and at standard atmospheric pressure.” A physical standard — a hunk of metal — was adopted a few years later.

Today, the kilogram standard is the only remaining measurement standard that is based on a physical artifact.

That means all the scales in the world are ultimately calibrated against a 125-year-old piece of metal kept in a vault on the outskirts of Paris. Its mass is the world’s definition of a kilogram.

Summer in the Sahara is scorching — sand temperatures can range between 149-158 degrees Fahrenheit. While skittering across the African desert at high noon might sound like a death wish, it’s only natural for the Saharan silver ant (Cataglyphis bombycina).

The insect emerges from its nest to forage midday and is capable of withstanding body temperatures up to about 127 degrees Fahrenheit. 

Picture of the Week: Kelvin-Helmholtz Clouds

Jul 29, 2015

Maybe you’ve seen tsunami-shaped clouds like these, rolling through Earth’s atmosphere. These repeating curls result from a flow of air hitting a layer of stagnant or slower-moving air below it. The turbulence is known as Kelvin-Helmholtz instability, named after its discoverers, William Thomson—better known as Lord Kelvin—and Hermann von Helmholtz.

July is National Ice Cream Month. Last July, a Cincinnati woman made national headlines when she made a discovery that shocked her.

After sitting out for hours in the summer heat, an ice cream sandwich still appeared intact and just slightly melted. What gives? What natural (or unnatural) ingredient could make this frozen treat withstand 80 degree temperature?

Climate change is imperiling bumblebees in the US and Europe

Jul 27, 2015

A recent report in the journal Science says climate change has caused bumblebee habitat to shrink by as much as 180 miles in the last 40 years — a pace researchers say is quite alarming.

Jeremy Kerr, the lead author on the study and a professor of biology at the University of Ottawa, says the bumblebee is caught in a kind of vice: its habitat is not extending northward to adjust to changing temperatures and the habitat in its southern range is diminishing.

Target grades: 4th +

Content Areas: General Science, Mathematics

Topics: Experimental design, variation, variables

Time required: 60 minutes, including lollipop-licking time


NGSS: Planning and Carrying Out Investigations

Picture of the Week: Saharan Silver Ant

Jul 24, 2015

Summer in the Sahara is scorching—sand temperatures can range between 149-158 degrees Fahrenheit. While skittering across the African desert at high noon might sound like a death wish, it’s only natural for the Saharan silver ant (Cataglyphis bombycina). The insect emerges from its nest in the ground to forage midday, capable of withstanding body temperatures up to about 127°F. 

Looks Fishy, Tastes Fishy. But Where's the Fish?

Jul 23, 2015

Eleven years ago, chef James Corwell had a revelation in Japan. He was teaching cooking to the U.S. Navy stationed there, and one morning, he woke up before dawn to make a pilgrimage to Tokyo’s Tsukiji fish market, the largest in the world. Under the roof of an open-air warehouse, he walked the aisles and perused row after row of hulking frozen tuna, steam rising from their carcasses. Corwell, one of the only certified master chefs in the United States, was astounded.

What Do You Know About Science?

Jul 22, 2015

This week on Science Friday, we’re going to talk about a recent study on expertise—and we need your help. We want you to unleash the geek, and let us know how familiar you are with a variety of scientific concepts.

Take a moment and fill out the form below. Then, tune in this Friday for a live discussion of the results with the study’s researchers.

Courtesy of Douglas Levere/

Students at the University at Buffalo will be helping NASA and the U.S. Air Force track debris in space.

Track a Plant's Movement

Jul 21, 2015

Though you may not realize it, every day the plants around you are moving…all by themselves. Even though most plants have roots that bind them to the surface they grow on, plants are able to stretch, grow, and bend to adjust to changes in their environment.

Right after Pearl Harbor, the US government began construction of a weapons factory on a site just outside of Denver, Colorado. Years later, the plant was converted into a pesticide factory. Now, the site is one of the nation's largest wildlife refuges — and, in part, it's thanks to that majestic American symbol, the bald eagle.

Is marijuana really an effective drug? Surprisingly, scientists have no solid answer

Jul 19, 2015

One would think that with medical marijuana now legal in 23 states, the science to support its efficacy would be fairly definitive. Surprisingly, that's not the case.

Despite the fierce political tussles and competing medical claims the truth is this: Very little solid scientific evidence exists to either confirm or dispute marijuana’s effectiveness as a drug or its potential for harm.

What Role Does the Sun Play in Vitamin D Synthesis?

Jul 18, 2015

This article is part of the SciFri Science Club's Explain the Sun activity. Participate using the hashtag #ExplainTheSun.

Picture of the Week: Cock-Eyed Squid

Jul 18, 2015

This activity is part of a Science Friday spotlight about cephalopods. Get involved using the hashtag #CephalopodWeek.

In the midst of “the twilight zone”—the ocean realm ranging from 200-1,000 meters below the surface—roams this small cephalopod.

Science Diction: Sun

Jul 18, 2015

This article is part of the SciFri Science Club's Explain the Sun activity. Participate using the hashtag #ExplainTheSun.

Throughout human history, the sun’s powerful energy has long assured its role as the undisputed “star” of our solar system.

Solar Convection

Jul 18, 2015

In this activity from Lawrence Hall of Science, you'll use hot and cold water to see how fluids at different temperatures move around in convection currents. 

Be sure to share what you've learned about the sun and convection during Science Friday's Science Club, using the hashtag #ExplainTheSun.

Age Level: 10 and up 


Preparation: 5 minutes 

Activity: 10 minutes

Cleanup: 5 minutes


This is Pluto — or, more specifically, a close-up of terrain bordering a heart-shaped feature dubbed “Tombaugh Regio,” for Pluto's discoverer, Clyde Tombaugh. The detail reveals a range of “young” mountains rising as high as 11,000 feet, which probably formed no more than 100 million years ago and might still be geologically active. 

NASA's New Horizons spacecraft captured the image about an hour and a half before making its closest approach to Pluto — a heralded arrival that occurred when many of us on the East Coast were eating breakfast this week.

Pluto probe makes closest approach this week

Jul 13, 2015
NASA/Johns Hopkins University Applied Physics Laboratory

For nine years, scientists have waited for this week to arrive. New Horizons, the piano-sized space probe launched back in January 2006, makes its closest approach to the distant world Pluto on Tuesday.

Microbes may hold the key to future high-tech meds and materials

Jul 11, 2015

When most people think about advanced technology, they imagine robots or hypersonic vehicles or new additions to the Internet of Things. But there is another tool that may have more high-tech potential than anything else: biology.

“Biology can do things that no other man-made technology or chemistry can do,” says Alicia Jackson, deputy director of the Biological Technologies Office at the Defense Advanced Research Projects Agency (DARPA).

The adult salamander pictured here has short limbs and toes, and gills sprouting from its head — features typical of amphibian larvae. But this species, known as the axolotl (pronounced ACK-suh-LAH-tuhl), is known for retaining these larva-like traits even after it reaches sexual maturity.

Everybody likes a good dinosaur story, but one of the best dinosaur stories of them all centers on the man who gave these remarkably extinct beasts their name.

Sir Richard Owen (1804-1892) was a celebrated naturalist and founder of the British Museum of Natural History. Some time around 1839, Owen began studying the bony remains of extinct races of reptiles: the carnivorous Megalosaurus, the herbivorous Iguanodon and the armored Hylaeosaurus. 

The crystal ball on a hilltop outside Boston doesn’t look into the future, but provides an invaluable connection to the past. This antique technology, called a Campbell-Stokes sunshine recorder, helps researchers maintain North America’s longest-running weather record.

A group of researchers have discovered the existence of previously unknown lymphatic vessels in the brain — a stunning find that upends current medical science and could have far-reaching implications for the study and treatment of neurological diseases like Alzheimers and multiple sclerosis.

Having trouble choosing the right cooking oil? So is everyone else.

Jul 3, 2015

Ever stood in the grocery aisle staring at 15 kinds of cooking oil, wondering which is the best one to buy? Which is the healthiest? Which is the best for cooking? Well, here are a few basic tips that might help.

How do those 'Jurassic World' dinos compare to the real thing?

Jul 3, 2015

Jurassic World, the long-awaited sequel to the monster hit, Jurassic Park, is finally here. Critics agree it is “visually dazzling,” but how does it rate with scientists who really know this stuff?

Apparently, the needle on the scientific Groan-o-Meter is pretty high on this one, though scientists are often loathe to spoil movie-goers’ fun.

A giant Pacific octopus looked like it was trying to devour Chris Payne. The 15-pound mollusk, currently donning bright-red coloration, swam near the edge of an aquarium tank and was wrapping her four-foot-long, powerful arms around Payne’s forearms.

She latched onto his exposed skin with dozens of white suckers, tasting him. “She’d love to pull me in,” says Payne, bracing himself against the floor. “But there’s no chance of that.” As if in response, the octopus shoots a mighty spray of water directly at Payne’s waist.

Michael Mroziak, WBFO

Two New York State lawmakers, from both houses and from both parties, joined in Buffalo Tuesday urging Governor Cuomo to sign legislation that provides a tax credit for property owners converting to a geothermal heating and cooling system.

The idea of large asteroids threatening the Earth and its habitants is not just the stuff of Hollywood, say scientists and advocates who are urging governments to do more to detect the deadly space rocks.

Repurposing drugs: How old vaccines are finding new uses

Jun 27, 2015

Repurposing works for shoes and even furniture, but what about drugs?

Researchers are looking at existing drugs already approved by the Food and Drug Administration for the treatment of one disease, to be used on another.

Dr. Denise Faustmann, the director of immunobiology at Mass General and associate professor of medicine at Harvard Medical School, is doing just that. She’s investigating whether diabetes could be treated with the common tuberculosis vaccine BCG.