“Here you will find a [browsable] collection of knots and links, viewed from a (mostly) mathematical perspective. Nearly all of the images here were created with KnotPlot, a fairly elaborate program to visualize and manipulate mathematical knots in three and four dimensions.” The diagrams are in color and are exceptionally clear.
Lithium is a Group 1 (IA) element containing just a single valence electron (1s22s1). Group 1 elements are called "alkali metals". Lithium is a solid only about half as dense as water. A freshly cut chunk of lithium is silvery, but tarnishes in a minute or so in air to give a grey surface.
The laws were formulated between 1609 to 16l9, and are (as usually stated):
<ul> <li> Planets move around the Sun in <strong>ellipses</strong>, with the Sun at one focus </li> <li> The line connecting the Sun to a planet sweeps <strong>equal areas in equal times. </strong></li> <li> The<strong> square</strong> of the orbital period of a planet is proportional to the <strong> cube</strong> (3rd power) of the mean distance from the Sun in (or in other words--of the"semi-major axis" of the ellipse, half the sum of smallest and greatest distance from the Sun) </li> </ul> <ol> </ol> <!--more--> <a href="http://www-spof.gsfc.nasa.gov/stargaze/Kep3laws.htm" target="_blank" rel="noopener noreferrer">Read more . . .</a><br />
This high-school level tutorial focuses on three topics: Astronomy of the Earth's motion in space, which includes information, and some experiments and projects that teach concepts about the calendar, seasons, Kepler's laws, building a sundial, and more; Newtonian mechanics, which ha understanding Newton's laws and discussion of mass and motion; and Spaceflight and Spacecraft. Includes a timeline, a list of concepts covered, and a glossary.
Clocks
How long is a day?
It's the amount of time it takes for the Earth to rotate one time on its axis. But how long does it take the Earth to rotate? That is where things become completely arbitrary. The world has decided to standardize on the following increments:
Adult humans typically have 32 teeth Continue reading Third Molar – Wisdom Teeth
OR, AND, NOT
OR logic collates the results to retrieve all the unique records containing one term, the other, or both. The more terms or concepts we combine in a search with OR logic, the more records we will retrieve
The more terms or concepts we combine in a search with AND logic, the fewer records we will retrieve.
A few Internet search engines make use of the proximity operator NEAR. A proximity operator determines the closeness of terms within the text of a source document. NEAR is a restrictive AND. The closeness of the search terms is determined by the particular search engine. Google defaults to proximity searching by default.
NOT logic excludes records from your search results. Be careful when you use NOT: the term you do want may be present in an important way in documents that also contain the word you wish to avoid.
NOUN: An airplane landing in which the two main wheels and the nose wheel, tail wheel, or tailskid all touch the ground simultaneously. Continue reading three-point landing
Baird was an early pioneer in this area, and one of the first techniques developed employed a system whereby the normal frame frequency was increased by a factor of three, each successive frame containing the material for one primary color. Continue reading Color television
Henry Gee investigates
Tuesday April 24, 2001 The Guardian
Once upon a time, many hundreds of millions of years ago, a few bacteria – a committee of microbes – got together to form the first eukaryote, the first cell with an organised nucleus.
Continue reading How small can a genome be and still remain functional?
| one of the three commonly recognized states in which matter occurs, i.e., that state, as distinguished from solid and gas, in which a substance has a definite volume but no definite shape. | 1 |
Win lose or draw
Dead to rights
Time is …
Frank Zappa
Physics has a law that explains everything. And it’s brought to you by the number three
The Symbolism and Spiritual Significance of the Number Three
COVID -19: Fabric masks should have three layers of different material
These Three Things Need to Happen Before Stocks Bottom Out, Credit Suisse Says
Coronavirus can stay infectious for 3 days on surfaces. But it’s still okay to check your mail.