Ever notice that when you spill coffee over the edge of your cup it always produces a ring under the bottom edge?
There is a rather complex reason for this, but it can be summed up somewhat easily. Two main factors are at play: surface tension of the molecules of the liquid and the temperature of the surrounding environment.
When a drop of coffee is splashed outside of the cup, it has an initial “pinned” spot, and from there the surface tension within the liquid causes the molecules to spread and draw more liquid away from it.
The temperature of the surrounding area then comes into play as a difference in temperature between the liquid and the air causes evaporation to begin. When an evaporating drop is checked under a microscope, there is a strong outward flow of material as the particles stream toward the edge, rather than moving around randomly. As the process continues, the molecules of the liquid continue to draw towards the edge and, because of their surface tension, they continue to draw more molecules towards them to replace liquid that has already evaporated. This continuous flow piles the material up at the edges, where it eventually dries and forms a ring.
No matter what type of liquid or different types of surface on which the liquid is spilled, all combinations still produce rings.
Scientists who have recently studied this phenomenon believe it has implications for industries that rely on the uniform deposition of solids suspended in liquid media (i.e., paints) and that dispersed solids could be deposited in a controlled fashion such as by creating tiny electronic circuits or providing a means of high-density information storage.
Originally posted in Headline Discoveries, January 2011
What is one of the best ways that you can leave your mark on your community or the world? Become a teacher! According to Henry Adams, a prominent 19th century journalist, professor, lobbyist, and world traveler, "A teacher affects eternity; he can never tell where his influence stops."
Using hands on teaching methods and interactive discussions, teachers are considered instructors, coaches, or facilitators in helping students learn and apply new educational concepts. In early educational levels, educators can use simple games to teach letters or numbers to preschoolers. As students get older, more sophisticated tools, such as computers or science apparatus can be used to teach complex concepts, develop critical thought processes, and reinforce problem solving skills.
Teachers are typically grouped according to the age level of students taught (Preschool, Kindergarten, Elementary School, Middle and Secondary School). Post-secondary Educators teach college-level courses and are desribed further along in this article.
Preschool TeachersPreschool teachers work with children who are old enough to be away from home for several hours a day, but too young to begin kindergarten. Their work involves using play activities (such as storytelling, rhyming, and acting) to improve the child's social skills, further language and vocabulary development, and introduce basic concepts of science and math. Creative activities may include art, music, and dance and may be presented on a one-on-one basis or as part of a group lesson.
The job of kindergarten teachers is much the same as that of a preschool teacher; however at this level, basic academics become more important. Letters and numbers, phonics, and a stronger awareness of science, nature, and the arts are subjects that are typically covered.
Elementary Schools Teachers
In most elementary schools, teachers are responsible for instructing one class of students in several subjects. In other schools, some teachers may be found who instruct only one subject to multiple classes (usually science, math, reading, physical education, art, or music).
Middle and Secondary School Teachers
Building on lessons taught in elementary school, middle and secondary school teachers help students by expanding on previously learned skills and by exploring new topics so they may gain information about the world around them. Classes such as history, biology, and foreign languages are offered and, often, middle and secondary school teachers can be found who specialize in these specific subjects.
Another educational specialty is a vocational education teacher, who can train students to work in a wide variety of fields (i.e.: technology, healthcare, auto repair).
Other responsibilities for teachers include monitoring homerooms and study halls, escorting students on field trips, and supervising extracurricular activities. They may also be involved in assisting students with various activities related to college and career exploration. Duties performed outside of the classroom often require educators to work more than 40 hours per week. An exception is preschool and kindergarten teachers who typically work on a part-time schedule. Traditional school years require most teachers to work for 10 consecutive months with a 2-month vacation held over the summer. Preschool teachers who work in a daycare setting often work year-round.
Licensing requirements for preschool teachers can vary by state. Public preschool teachers are generally subjected to higher requirements than those teaching at private preschools. In some states a bachelor's degree in early childhood education is required, while others only require an associate's degree. Some states require certification by a nationally recognized authority. The most common type of certification, The Child Development Associate (CDA)credential, requires a combination of classroom training and experience, in addition to an independent assessment of an individual's competence.
Public school teachers are required to be licensed to work in all 50 states and the District of Columbia. Private schools teachers are not required to be licensed. A State Board of Education or a licensure advisory committee usually grants licensure.
State requirements for licenses to teach kindergarten through 12th grade vary. All states require a bachelor's degree and the completion of an approved teacher training program as well as supervised practice teaching. Technology training and the attainment of a minimum grade point average is becoming more common in some states, and some states require that teachers earn a master's degree in education within a designated period of time after they begin teaching. Most states require continuing education for renewal of a teacher's license.
Individuals who are post-secondary teachers usually work as professors, assistant professors, instructors, and/or lecturers. These are all "tenure track" positions, meaning a tenured professor may not be fired without good reason or due process. Tenure exists in an effort to preserve academic freedom for professors - thus ensuring that they will not be fired for espousing controversial opinions. Part-time instructors, known as adjunct faculty members, usually are not eligible for tenure.
Courses for undergraduate or graduate students are taught by post-secondary educators who typically instruct in one or more subjects within a prescribed curriculum. These teachers are responsible for the preparation and delivery of lectures and associated course materials/components (bibliographies, tests, reading assignments, research, in-class demonstrations, guest lecturers, etc.) pertinent to the subject being taught. In addition, administration and grading of examinations is part of their job. Post-secondary teachers often conduct research in their particular field of interest and publish their findings in professional journals. They may also direct the research of other teachers or graduate students who are working to obtain an advanced degree in the same field. Other duties can include acting as an advisor to students or student organizations, and providing service on faculty committees.
For post-secondary educators, WetFeet.com reports that "College and university faculty should enjoy an increasing number of employment opportunities as well, but competition for those jobs will be intense, particularly for tenure-track positions. And as colleges and universities face increasing budget constraints, more and more teaching positions will go to contract workers."
Potential earnings can vary widely based on many factors, some of which may include the following:
With skills and personal attributes such as organization, communication, motivation, creativity, patience, diligence, and commitment, individuals can succeed in a rewarding career as a teacher and work towards their passion for ensuring a high-quality education for the children and adults that come into their classroom.
Currently live on Teaching.org
I'm April Bailey, a freelance writer and editor for hire who has been writing about various topics for many years. Most of my early print work was destroyed in a major house fire. Luckily, I was able to pull some copies from an old PC and have posted them here. Other items on this blog reflect my current articles and blog posts written for online publications and copied here so I never lose my work again!