chemistry

Throbber

Throbber is a chemistry topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Throbber rather than just read about it. In short: A throbber, also known as a loading icon, is an animated graphical control element used to show that a computer program is performing an action in the background, such as downloading content, conducting intensive calculations, or communicating with an external device. In contrast to a progress bar, a throbber does not indicate how much of the action has been completed.

Key takeaways

Throbber belongs to chemistry; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Throbber to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Throbber from memory before moving on to harder problems.

Reference excerpt

A throbber, also known as a loading icon, is an animated graphical control element used to show that a computer program is performing an action in the background, such as downloading content, conducting intensive calculations, or communicating with an external device. In contrast to a progress bar, a throbber does not indicate how much of the action has been completed.

History An early use of a throbber occurred in the NCSA Mosaic web browser of the early 1990s, which featured an NCSA logo that animated while Mosaic downloaded a web page. As the user could still interact with the program, the pointer remained normal (and not a busy symbol, such as an hourglass); therefore, the throbber provided a visual indication that the program was performing an action. The Netscape web browser also featured a throbber. In version 1.0 of Netscape, this took the form of a big blue "N" (Netscape's logo at the time). The animation depicted the "N" expanding and contracting – hence the name "throbber". The IBM WebExplorer offered a webpage the opportunity to change the look and the animation of the throbber by using proprietary HTML code. The Arena web browser has a command-line option to change the throbber with a local file.

Spinning wheel

Throbbers also appear in client side applications (such as Ajax web apps) where an application within the web browser would wait for some operation to complete. Most of these throbbers appear as a "spinning wheel", which typically consist of 8, 10, or 12 part-radial lines or discs arranged in a circle, as if on a clock face, highlighted in turn as if a wave is moving clockwise around the circle. In text user interfaces and command lines, the spinning wheel is commonly replaced by a fixed-width character which is cycled through discrete states, such as "|", "/", "-" and "\", which act as the frames of a looping animation-like effect. Unlike graphical activity indicators, this style of throbber is commonly paired with a progress display like a bar, since the lower effective resolution of character-based progress bars can benefit from a separate indication of activity. Often, the spinner is displayed at or near the position of the typing cursor, then called a "spinning cursor" or "rotating cursor". This style of throbber dates from versions of UNIX appearing in the latter 1970s, and DR-DOS utilities in the 1980s, since it requires at least a character-cell addressable display—i.e. one which can be updated quickly to make precise changes to already displayed text—but given that is otherwise simple to program.

See also Spinning pinwheel Windows wait cursor

References

Illustrations

Worked examples

Example 1 — a first encounter with Throbber

Start with the simplest possible case. Write down what Throbber claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In chemistry, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Throbber before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Throbber ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Throbber

In research: Throbber appears in chemistry research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Throbber in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Throbber is common in secondary-school and first-year university syllabi. It links to neighbouring topics Graphical control elements, Technology neologisms, so understanding it makes those chapters shorter.
In everyday life: Look for Throbber outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Throbber in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Throbber means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Throbber out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Throbber in simple terms?

Why does Throbber matter?

Because it connects several chemistry ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Throbber?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Throbber.