physics

Wheat

Wheat is a physics 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 Wheat rather than just read about it. In short: Wheat is a group of wild and domesticated grasses of the genus Triticum (). As cereals, they are cultivated for their grains, which are staple foods around the world.

Key takeaways

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

Reference excerpt

Wheat is a group of wild and domesticated grasses of the genus Triticum (). As cereals, they are cultivated for their grains, which are staple foods around the world. Well-known wheat species and hybrids include the most widely grown common wheat (T. aestivum), spelt, durum, emmer, einkorn, and Khorasan or Kamut. The archaeological record suggests that wheat was first cultivated in the regions of the Fertile Crescent around 9600 BC. Wheat is grown on a larger area of land than any other food crop (219.5 million hectares or 542 million acres in 2024). World trade in wheat is greater than that of all other crops combined. In 2024, world wheat production was 799 million tonnes (881 million short tons), making it the second most-produced cereal after maize (known as corn in North America and Australia). Since 1960, world production of wheat and other grain crops has tripled and is expected to grow further through the middle of the 21st century. Global demand for wheat is increasing because of the usefulness of gluten to the food industry. Wheat is an important source of carbohydrates. Globally, it is the leading source of vegetable proteins in human food, having a protein content of about 13%, which is relatively high compared to other major cereals but relatively low in protein quality (supplying essential amino acids). When eaten as the whole grain, wheat is a source of multiple nutrients and dietary fibre. In a small part of the general population, gluten – which comprises most of the protein in wheat – can trigger coeliac disease, noncoeliac gluten sensitivity, gluten ataxia, and dermatitis herpetiformis.

Description

Wheat is a stout grass of medium to tall height. Its stem is jointed and usually hollow, forming a straw. There can be many stems on one plant. It has long narrow leaves, their bases sheathing the stem, one above each joint. At the top of the stem is the flower head, containing some 20 to 100 flowers. Each flower contains both male and female parts. The flowers are wind-pollinated, with over 99% of pollination events being self-pollinations and the rest cross-pollinations. The flower is housed in a pair of small leaflike glumes. The two (male) stamens and (female) stigmas protrude outside the glumes. The flowers are grouped into spikelets, each with between two and six flowers. Each fertilised carpel develops into a wheat grain or berry; botanically a caryopsis fruit, it is often called a seed. The grains ripen to a golden yellow; a head of grain is called an ear. Leaves emerge from the shoot apical meristem in a telescoping fashion until the transition to reproduction i.e. flowering. The last leaf produced by a wheat plant is known as the flag leaf. It is denser and has a higher photosynthetic rate than other leaves, to supply carbohydrate to the developing ear. In temperate countries the flag leaf, along with the second and third highest leaves on the plant, supply the majority of carbohydrate in the grain; their condition is critical for crop yield. Wheat is unusual in having more stomata on the upper (adaxial) side of the leaf, than on the under (abaxial) side. It has been theorised that this might be an effect of having been cultivated longer than any other plant. Winter wheat generally produces up to 15 leaves per shoot, and spring wheat up to 9; winter crops may have up to 35 tillers (shoots) per plant (depending on cultivar). Wheat roots are among the deepest of arable crops, extending as far down as 2 metres (6 ft 7 in). While the roots of a wheat plant are growing, the plant accumulates an energy store in its stem, in the form of fructans, which helps the plant to yield under drought and disease pressure, but there is a trade-off between root growth and stem non-structural carbohydrate reserves. Root growth is likely to be prioritised in drought-adapted crops, while stem non-structural carbohydrate is prioritised in varieties developed for countries where disease is a bigger issue. Depending on variety, wheat may be awned or not. Producing awns incurs a cost in grain number, but wheat awns photosynthesise more efficiently than leaves with regards to water usage, so awns are much more frequent in varieties of wheat grown in hot drought-prone countries than those in temperate countries. For this reason, awned varieties could become more widespread due to climate change. In Europe, wheat's climate resilience has declined.

History

Domestication

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Wheat

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

In research: Wheat appears in physics 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 Wheat 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: Wheat is common in secondary-school and first-year university syllabi. It links to neighbouring topics Agricultural economics, Botanical taxa named by Carl Linnaeus, Crops, so understanding it makes those chapters shorter.
In everyday life: Look for Wheat 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.

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Wheat in 20 minutes

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

Frequently asked questions

What is Wheat in simple terms?

Wheat is a group of wild and domesticated grasses of the genus Triticum (). As cereals, they are cultivated for their grains, which are staple foods around the world.

Why does Wheat matter?

Because it connects several physics 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 Wheat?

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 Wheat.