Chemistry

Researchers have set out to solve the mystery of a degenerative sign of aging in concrete: the alkali-aggregate reaction (AAR), where a material forms that takes up more space than the original concrete and thus gradually cracks the concrete from within as the decades go by. The researchers have now explored the exact structure of this material. They managed to demonstrate that its atoms are arranged extremely regularly, making it a crystal. They also showed that the structure of this crystal is a so-called sheet-silicate structure. This specific structure had never been observed before.…

In what might be a new breakthrough for the spider-control field, researchers have found that oil-based pesticides are more effective than water-based pesticides at killing the contents of brown widow spider egg sacs. This finding is important because trying to control adult spiders without controlling their eggs is like plucking dandelions without taking out their roots. This image shows a brown widow spider. Credit: Rick Vetter "The brown widow spider egg sac is constructed with highly hydrophobic silks, so the water-based pesticide sprays were not very effective in…

Methane hydrates are a kind of ice that contains methane, and that form at certain depths under the sea or buried in permafrost. They can also form in pipelines that transport oil and gas, leading to clogging. Yet methane hydrates are nearly impossible to study because it is very hard to get samples, and the samples themselves are highly unstable in the laboratory. A team of scientists from Norway, China and the Netherlands has now shown how the size of grains of the molecules that make up the natural structure of methane hydrates determines how they behave if they are loaded with weight or…

In a new thesis, 60 garments from Swedish and international clothing chains have been tested and though around a hundred chemicals were preliminary identified, several of the substances were not on the producers' lists and are suspected to be by-products, residues or chemicals added during transport. Dependent on occurrence, quantity, toxicity and how easily they may penetrate the skin, four groups of substances were chosen for further analysis. The highest concentrations of two of these, quinolines and aromatic amines, were found in polyester. Cotton contained high concentrations of…

You’ve probably had subscriptions to newspapers, magazines, or even Netflix. Fairly recently the subscription box has emerged like Loot Crate, filled with Sci-Fi/Fantasy/Comic book themed T-shirts, mugs, minifigures and such. Now there’s a subscription box chemistry set from MEL Science. “We have reinvented educational chemistry sets for kids,” says Vassili Philippov, CEO of Mel Science. “It includes chemical reagents for real experiments, a mobile app, and a virtual reality headset to let you visualize molecules in 3D.” A kit that teaches science to kids should keep them engaged in…

Processing fabric for the latest fashions and other textile-based products today requires thousands of chemicals, some of which are toxic and cause 20 percent of the world's water pollution. To reduce its environmental footprint, the textile industry is making changes, designing safer chemicals and turning to nature to find replacements to potentially harmful compounds, according to an article in Chemical&Engineering News. Alex Scott, a senior editor at C&EN, notes that the polluting agents used to make clothes include dyes, fixing agents, bleaches, solvents and detergents. These…

The fishing port of Ondarroa, the Deba marina, the estuary at Gernika (beside the discharge stream of the waste water treatment plant) and the industrial ports of Pasaia and Santurtzi are the scenarios where the research was carried out between May and June 2012. The fish chosen for the study was the thicklip grey mullet (Chelonlabrosus). Water samples were taken from the above-mentioned locations on the days when the mullet were caught and three months later to relate the samples to the concentrations of the compounds in the fish. "As we expected, Gernika was where the highest concentration…

Recent media stories have reported on two new scientific studies involving BPA’s effects on birth weight.  One study reported a statistical association between prenatal exposure to BPA and increased birth weight, while the other reported an association with decreased birth weight.  However, both of the new studies use cross-sectional study designs that are inherently incapable of providing much meaningful information on whether exposure to BPA has any effect on birth weight.  Furthermore, the BPA exposure measurements reported in one of the studies are not likely to be valid at…

Here are three experiments. I don't recommend that you try any of them, but, since we are adults, and presumably still have some free choice about our actions, do as you see fit.Experiment #1  Purchase a can of pure sodium metal Go to New York Stand in front of the Empire State Building Using a knife, cut the sodium into a cube, roughly one inch per side Place the cube in your mouth, bite down firmly, making sure that your lips are sealed Record the results. OK, #6 is not realistic. You won't be recording any results, but the bomb squad will. Their results will look something like this…

Most people are able to recognize the smell of “death” when they encounter a dead animal on a farm or a roadkill. But despite its distinctive scent, few know why it actually smells the way it does. Even forensic scientists may not have identified all of the compounds behind it yet – they are still in the process. Understanding the pattern of change of the chemicals that make up the scent during the process of decomposition could be of huge benefit to forensic science. Not only could it help determining the time of death of a victim, it could also lead to more scientifically rigorous…