What Makes Ice Slippery Compared to Other Solids? A Combination of Factors?

Chemistry, Physics
[caption id="attachment_17673" align="alignleft" width="380"] Image: Tvb hof - Own work, CC BY-SA 3.0[/caption] “Be careful if you will be driving this evening,” the weather forecaster declares. “The road will be a sheet of ice.” Whether tar and gravel, asphalt, or concrete, roads most of the year are not slippery. Yet come winter, those roads can be dangerously slippery. What makes ice and icy roads so slippery? What Makes Ice Slippery One line of thinking is that ice is slippery because water (H₂O) expands as it freezes. When a heavy object rests upon a sheet of ice, the pressure imparts energy to the molecules immediately beneath the weight, pressing them down, melting it. The water acts much like a lubricant, making the ice slippery. In truth, if the ice is reasonably…
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Differences between Spider Silk and Cocoon Silk

Chemistry, Technology
[caption id="attachment_17656" align="alignright" width="440"] The Madagascar golden orb spider silk cape. Image CCA-SA 3.0 Unported by Cmglee[/caption] Spider silk and cocoon silk... What, if any, are the differences between these two materials? Spider Silk: An Overview Spider silk is a derivative of the structural protein fibroin, which consists largely of alanine (ALA) and glycine (GLY) amino acid sub-units. These two acids constitute about 67% of the total. Serine and other amino acids make up the remainder. There is a variety of forms of spider silk. Different specific glands are responsible for the different forms of silk. Most notable among silk varieties are dragline silk and capture silk. How do these two varieties compare? Dragline Silk Dragline silk is strong, but possesses a measurable degree of flexibility and extensibility. This variety…
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Where Do Trees Come From? From Heaven or Earth?

Chemistry, Plants
Where do trees come from, from heaven or earth? This is not the philosophical discussion it might at first seem to be. Even in the Bible, heaven sometimes refers, not to the residence of the Almighty, but to that region of the atmosphere in which birds fly.¹ Do trees come from the soil or from the air? Most would probably say, “from the soil.” But is that the case? What are trees primarily made of? Largely they consist of cellulose and sugar, although there are smaller quantities of other substances. Cellulose is simply sugar molecules linked together with the loss of a single molecule of water between each sugar molecule. The molecules that build up a tree are carbon-based. There are traces of other substances, but only traces. For instance,…
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Jewelweed and Its Special Ingredient Lawsone – Poison Ivy Begone?

Chemistry, Plants
[caption id="attachment_17591" align="alignright" width="480"] Jewelweed - Image by Fritz Geller-Grimm CC by SA 2.5[/caption] Orange jewelweed (Impatiens capensis)1 commonly grows in ditches along roadsides at the edges of moist forests. Lore has it that the sap of this plant rubbed onto poison ivy rash quickly alleviates the itching. Could there be a scientific basis for this popular notion? Perhaps. Let’s begin our consideration by discussing the active principle in both poison ivy and jewelweed. Poison Ivy and Urushiol Urushiol is not a single compound, but a mixture of similar compounds that have the generic chemical structure show in the image associated with this article. R represents an alkyl chain that typically contains 15 to 17 carbon atoms that contain varying numbers of double bonds. The greater the number of double…
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Hydrogen Sulfide or Hydrogen Cyanide: Which is More Dangerous?

Chemistry, Health
School kids laugh when malodorous body noises break the silence. “Jimmy just gassed,” little Susie giggles. Such odors are associated with the sulfur that comes from eating eggs, although that is by no means the only source. In fact, the odor that comes from eating eggs is thought by high school students to be due to hydrogen sulfide, H₂S. It is generally thought of as a nuisance, and not as a poison. Another familiar odor is associated with the pit or seed of a peach—bitter almonds. The source of the odor in this case is hydrogen cyanide, HCN. Hydrogen cyanide and its sodium and potassium salts, NaCN and KCN, are often the victim’s cause of death in a television mystery. But… in “real life”… what is the story? Just how…
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Does Pineapple Weed or Wild Chamomile Grow in Your Lawn?

Chemistry, Plants
[caption id="attachment_17548" align="alignright" width="440"] Mystery plant. Image S. Korte.[/caption] I take a measure of pride in being able to identify various tiny weeds in the spring of the year. Pointing them out to a car-group of friends, one of them adventured out on their own and brought back a tiny plant I felt sure I could make quick work of. But the little plant, with its almost lacy leaves and tiny egg-shaped yellow ‘flower’ mystified me completely. I sniffed it and detected a most unusual odor that nevertheless was not unpleasant. It resembled a cross between a tiny evergreen tree and an egg or pineapple. It was not a pineapple, but it was wild chamomile or the pineapple weed (Matricaria discoidea). Research cited below, by Daise Lopes & Paul P.…
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Dutchman’s Breeches – Flowering Jewels of Early Spring

Chemistry, Plants
[caption id="attachment_17508" align="alignright" width="440"] Dicentra cucullaria - Image own work Fritzflohrreynolds CCA-SA3.0 Unported[/caption] With a name reminiscent of trousers or undergarments, we wouldn’t expect Dutchman's Breeches (Dicentra cucullaria) to be particularly beautiful. A cluster of these jewels caught my attention during a search for the elusive morel mushroom. Even though I’d never seen Dutchman’s Breeches before, I instantly recognized the treasure I’d found. It was a bit of a lucky guess, as Squirrel Corn (Dicentra canadensis) is very similar. Why So Beautiful What makes Dutchman's Breeches so beautiful? Quite often, a plant possesses beauty a single component, whether the flower or the leaf, or even overall form. But for D. cucullaria, every component part of the plant is beautiful, even its rootstock as can be seen from this Missouri Department…
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Graphene Properties, Applications, and Production

Chemistry, Physics
[caption id="attachment_16970" align="alignright" width="406"] Graphene Lattice - By AlexanderAlUS - Own work, CC BY-SA 3.0[/caption] Carbon varieties include diamonds, graphite1, soot, Buckminsterfullerene, and tiny nanotubes. Despite these amazing forms, there is still another form of carbon, perhaps the most amazing of all. Graphene. Discovery Graphene is a super material. For its successful isolation, André Geim and Konstantin Novoselov, were awarded the 2010 Nobel prize. Each sheet is one atom thick. It resembles a hurricane fence. First Production The first effort at isolation involved thinning a pad of graphite. Adhesive tape was attached to the sides of the pad it was pulled apart. In time, a single layer was left. There are two easy ways to visualize this. First, imagine a flaky biscuit with many layers. You peel the layers off,…
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Turpentine Pine Tree Resin Products: Why So Valuable?

Chemistry, Plants
[caption id="attachment_16454" align="alignright" width="380"] Pine resin. CCA 3.0 SA Unported Maksim.[/caption] Turpentine was once a very common household solvent. It seemed as if every household had a can in their garage. Turpentine is produced by distillation of pine tree resin. The solid remaining after distillation is called rosin. Doubtless the decreased household use of turpentine is because of an increase in water-based products such as paints, replacing oil-based equivalents. Petroleum based solvents have contributed to the decline. Solvent Only? Still, turpentine is more than just a useful solvent. It can be separated into fragments sometimes referred to as isolates. The primary isolate is pine oil, which is used, among other things, in household cleaners. Turpentine yields compounds that are useful in chemical synthesis. Chemicals readily available from nature that can…
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Short, Medium, and Long Grain Rice Vary in Use and Starch Profile

Chemistry, Food
Rice is, technically, grass seed! It is the most widely consumed food staple in the world. Rice is a dietary starch, as are maize and potatoes. There are nearly innumerable commercially available rice varieties—more than 40,000. One means of classifying rice varieties is by grain length. Rice of varying grain lengths vary also in starch profiles. Perhaps the most popular rice in the Western World is long grain rice. Starch Profile versus Grain Length L.G. rice features grains about four to five times as long as they are wide. It is sometimes sold as brown rice. However, frequently it is milled or polished to remove the bran. It is then sold as white rice. What is the starch profile of this form of rice? The two most important starches are…
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