19Apr 2017 by Vincent Summers 2 Comments

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…
Read More
25Sep 2015 by Vincent Summers No Comments

Oil and Water Do Not Mix – Why?

Chemistry
[caption id="attachment_8586" align="alignright" width="440"] Oil and water just plain do not mix.[/caption] Oil and water do not mix! Some liquids are miscible; that is, they mix completely. Other liquids do not permanently mix. They are immiscible. The best known example of this is oil and water. “Putting those two together is like mixing oil and water.” This means that for practical purposes, the two don’t get along at all. Why Don’t They Mix? Oil and water don’t mix for a basic physical reason curiously easy to explain by comparison with a magnet. Consider first the formula, and then the structure, of water and we’ll see how this is so. The Formula of Water Water is most commonly written H₂O. Two hydrogen atoms (H) are combined with one oxygen atom (O).…
Read More