String

Key takeaways

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

Reference excerpt

String is a long flexible tool made from fibers twisted together into a single strand, or from multiple such strands which are in turn twisted together. String is used to tie, bind, or hang other objects. It is also used as a material to make things, such as textiles, and in arts and crafts. String is a simple tool, and its use by humans is known to have been developed tens of thousands of years ago. String may also be a component in other tools, and in devices as diverse as weapons, musical instruments, and toys. The ubiquity of string as a tool has led to conceptual and scientific uses of the term, including strings in computer science, cosmic strings, and string theory.

History String, along with twine and other cordage, was used in prehistoric times for hafting sharp stone tips onto spears, in beadwork, to ease firelighting (as part of a bow drill), as well as for fishing lines and nets, clothing, shelter-making materials, bow string, sutures, traps, and countless other uses. Bow drills, which use string as the mechanism for turning a drill bit, were used in Mehrgarh between the 4th and 5th millennium BC. Similar drills were found in other parts of the Indus Valley civilization and Iran one millennium later. In Roman times, the same principle also was used widely in drilling for purposes of woodworking and dentistry.

Physical types and uses There are many types of string, adapted to many uses. The following subsections summarize common categories.

Twine

Twine is a light string or strong thread composed of two or more smaller strands or yarns twisted, and then twisted together. More generally, the term can be applied to a cord. Natural fibres used for making twine include cotton, sisal, jute, hemp, henequen, and coir. A variety of synthetic fibres are also used.

Yarn

Yarn is a long continuous length of interlocked fibres, suitable for use in the production of textiles, sewing, crocheting, knitting, weaving, embroidery, and ropemaking. Thread is a type of yarn intended for sewing by hand or machine. Modern manufactured sewing threads may be finished with wax or other lubricants to withstand the stresses involved in sewing. Embroidery threads are yarns specifically designed for hand or machine embroidery.

Thread

Thread is a type of yarn used for sewing and knitting. Thread is made from a wide variety of materials. The following table lists common materials, a general description and what they are supposed to be good for. If your machine will sew with the thread, any thread can be used for just about any purpose. This is very useful for someone who is trying to learn sewing. However, it should be remembered that where a thread is stronger than the material that it is being used to join, if seams are placed under strain the material may tear before the thread breaks. Garments are usually sewn with threads of lesser strength than the fabric so that if stressed the seam will break before the garment. Heavy goods that must withstand considerable stresses such as upholstery, car seating, tarpaulins, tents, and saddlery require very strong threads. Attempting repairs with light weight thread will usually result in rapid failure, though again, using a thread that is stronger than the material being sewn can end up causing rips in that material before the thread itself gives way.

Bowstring

A bowstring joins the two ends of the bow stave and launches the arrow. Desirable properties include light weight, strength, resistance to abrasion, and resistance to water. Mass has most effect at the center of the string; one gram (0.035 oz) of extra mass in the middle of the string slows the arrow about as much as 3.5 grams (0.12 oz) at the ends. Traditional materials include linen, hemp, other vegetable fibers, sinew, silk, and rawhide. Almost any fiber may be used in emergency.

Drawstring

A drawstring (draw string, draw-string) is a string, cord, lace, or rope used to "draw" (gather, or shorten) fabric or other material. The ends of the drawstring may be tied to hold it in place (and/or simultaneously close an opening). Alternately, the drawstring may be kept drawn using a cordlock. Typically, the drawstring is loose when not being used, and tightened when needed during use.

Pullstring

A pullstring (pull string, pull-string), pullcord (pull cord, pull-cord), or pullchain (pull-chain, pull chain) is a string, cord, or chain wound on a spring-loaded spindle that engages a mechanism when it is pulled. It is most commonly used in toys and motorized equipment. More generally and commonly, a pullstring can be any type of string, cord, rope, chain, or cable attached to an object in some way used to pull or mechanically manipulate part of it.

Shoestrings

Shoelaces, also called shoestrings (US English) or bootlaces (UK English), are a system commonly used to secure shoes, boots and other footwear. They typically consist of a pair of strings or cords, one for each shoe, finished off at both ends with stiff sections, known as aglets. Each shoelace typically passes through a series of holes, eyelets, loops or hooks on either side of the shoe. Loosening the lacing allows the shoe to open wide enough for the foot to be inserted or removed. Tightening the lacing and tying off the ends secures the foot within the shoe.

Strings in music and sport

Musical instrument strings

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with String

Start with the simplest possible case. Write down what String claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, 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 String 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 String 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 String

In research: String appears in science 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 String 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: String is common in secondary-school and first-year university syllabi. It links to neighbouring topics Fasteners, Fibers, so understanding it makes those chapters shorter.
In everyday life: Look for String 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.

How to study String in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what String 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 String out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is String in simple terms?

String is a long flexible tool made from fibers twisted together into a single strand, or from multiple such strands which are in turn twisted together. String is used to tie, bind, or hang other objects.

Why does String matter?

Because it connects several science 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 String?

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 String.