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Redgra

Redgra is a science 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 Redgra rather than just read about it. In short: Redgra, sometimes styled as RedGra, Red-Gra, or generically as redgra, is the brand name of an all-weather surfacing material primarily composed of red clay and fine limestone gravel. It is used on baseball diamonds, running tracks and long jump run-ups, and hard-surface association football, netball, cricket, and field hockey pitches in the United Kingdom.

Key takeaways

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

Reference excerpt

Redgra, sometimes styled as RedGra, Red-Gra, or generically as redgra, is the brand name of an all-weather surfacing material primarily composed of red clay and fine limestone gravel. It is used on baseball diamonds, running tracks and long jump run-ups, and hard-surface association football, netball, cricket, and field hockey pitches in the United Kingdom.

History Outdoor field hockey in the United Kingdom during the 1910s and 1920s often relied on heavy clay surfaces that were unplayable after heavy rain or under frost. Teams would fall back to more durable, but harsher, tarmac surfaces. To address this, tennis court contractors Grimshaw Sports developed Redgra in 1959 by adapting the company's existing mix used for tennis courts. The limestone and clay were sourced from the Forest of Dean, Gloucestershire. The material was designed for the United Kingdom's first all-weather outdoor field hockey pitches. One of the first academic applications was opened on 4 March 1961 at Dean Close School under the recommendation of Olympic field hockey bronze medalist Denys Carnill for the school's field hockey team. A Redgra area was opened in October 1961 at the site of Harlow Sportcentre, which was completed in 1964. In 1964, the Crystal Palace National Recreation Centre included a Redgra training area and separate football practice pitch. Redgra also saw use in other pavement applications, such as garden paths and car parks.

Properties Redgra can be applied similarly to sand, binds itself when wet and compacted, and solidifies after 24 hours. As a sports surface, Redgra allowed for year-round use with minimal maintenance in academic and practice settings, and allowed for multi-sport use as tennis courts. Its natural components were inexpensive and simple to install. A Redgra field hockey pitch installed at Cranleigh School and opened on 1 February 1968 cost £4,500 for materials and lasted until 2005. The resulting surface was porous, allowing for easy drainage, and frost-resistant. Pat Ward-Thomas, a writer for The Guardian, noted that contemporary surfaces often failed to provide smooth, precise, and predictable ball movement but praised the Redgra pitch's performance. While competitive teams still often favored playing on well-maintained grass surfaces, Redgra surfaces sometimes substituted when rain or poor maintenance made grass unsuitable. Redgra also saw use in playground football, youth clubs, and some women's and lower-tier men's football clubs into the 1990s. The first training pitch for Chelsea Ladies F.C. in 1992, then composed mostly of under-18 players, was a Redgra surface at a community college near Feltham.

Drawbacks Even upon its unveiling, Redgra was considered adequate for training surfaces but questionable as a full-time competitive surface. Redgra has a reputation for causing abrasions and splinters when sliding on it compared to grass, and its hardness contributed to injuries when falling on it. When dry, the surface generated considerable amounts of red dust. The surface could become alternately sticky and slippery in frosty conditions, and if improperly drained could become muddy.

Replacement Since the 1990s, many Redgra installations for field hockey and association football have been supplanted by newer all-weather surfaces, such as artificial turf, that are more similar to natural grass or have impact-cushioning layers. However, it remains in use for public recreation tracks. While an artificial surface, Redgra's natural components don't present the same concerns to landfills upon disposal as rubber or other synthetic surfaces.

References

Worked examples

Example 1 — a first encounter with Redgra

Start with the simplest possible case. Write down what Redgra 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 Redgra 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 Redgra 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 Redgra

In research
Redgra 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 Redgra 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
Redgra is common in secondary-school and first-year university syllabi. It links to neighbouring topics Clay, Limestone, Pavements, so understanding it makes those chapters shorter.
In everyday life
Look for Redgra 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 Redgra in 20 minutes

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

Frequently asked questions

What is Redgra in simple terms?

Redgra, sometimes styled as RedGra, Red-Gra, or generically as redgra, is the brand name of an all-weather surfacing material primarily composed of red clay and fine limestone gravel. It is used on baseball diamonds, running tracks and long jump run-ups, and hard-surface association football, netba…

Why does Redgra 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 Redgra?

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 Redgra.

Tags

  • Clay
  • Limestone
  • Pavements
  • Playing field surfaces
  • Tennis court surfaces

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