Explain why ball point and fountain pens stop writing when used upside down portion
Answers
Explanation:
Because of a ballpoint pen's reliance on gravity to coat the ball with ink, most cannot be used to write upside-down.
Answer:
( BALL POINT )
A ballpoint pen, also known as a biro or ball pen, is a pen that dispenses ink (usually in paste form) over a metal ball at its point, i.e. over a "ball point". The metal commonly used is steel, brass, or tungsten carbide. The design was conceived and developed as a cleaner and more reliable alternative to dip pens and fountain pens, and it is now the world's most-used writing instrument; millions are manufactured and sold daily. It has influenced art and graphic design and spawned an artwork genre.
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( FOUNTAIN PEN )
While the earliest record of a fountain-like pen dates from the 10th century, fountain pens as we know them today didn’t exist until the late 19th century. In 1884, an American named Lewis Waterman patented the first practical model after supposedly having a sales contract ruined by a leaky precursor. Before Waterman’s version, fountain pens were plagued with ink spills and blots, and were unreliable and inconvenient.
The main problem of earlier fountain pens centered on airflow — there wasn’t enough. Fountain pens work by managing the rate at which the ink flows through the pen. When the pen is held at an upright angle, ink from the reservoir is drawn downward by gravity, and goes through the feed and to the nib in a controlled fashion. Unless air is brought into the reservoir to replace the ink as it is used, a vacuum will build up that stops the flow.
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