Lewis structure of water The Lewis structures, also called Lewis-dot diagrams or electron dot diagrams are pictures that show the bonding between a pair of electrons and the atoms of a molecule. Each dot represents one electron. Two dots side by side represent a lone pair of electrons. To show a bond between atoms, a line representing a pair of shared electrons is placed between the two atoms.
Or, maybe you're wondering just how old the tires are on the motorcycle you just bought. Here's how to tell: Look on the sidewall of the tire for the DOT symbol. Follow the line of text and numbers after the DOT symbol until you reach the end. If the tire was manufactured in the year 2000 or later, the last 4 digits give the age. The last 2 digits give the year and the preceding 2 digits give the week of manufacture.
The second two represent the year. A tire with a DOT code of 1109 was made in the 11th week of 2009. Tires with a three-digit code were made prior to 2000 and are trickier to decode. The first two digits still tell you the week, but the third digit tells you the year in the decade that it was created.The hard part is knowing what decade that was.or years, people have relied on a tire's tread depth to determine its condition. But the rubber compounds in a tire deteriorate with time, regardless of the condition of the tread. An old tire poses a safety hazard. For some people, old tires might never be an issue.