physics

Johann Wilhelm Hittorf

Johann Wilhelm Hittorf 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 Johann Wilhelm Hittorf rather than just read about it. In short: Johann Wilhelm Hittorf (27 March 1824 – 28 November 1914) was a German physicist who was born in Bonn and died in Münster, Germany. Hittorf was the first to compute the electricity-carrying capacity of charged atoms and molecules (ions), an important factor for understanding electrochemical reactions.

Key takeaways

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

Reference excerpt

Johann Wilhelm Hittorf (27 March 1824 – 28 November 1914) was a German physicist who was born in Bonn and died in Münster, Germany. Hittorf was the first to compute the electricity-carrying capacity of charged atoms and molecules (ions), an important factor for understanding electrochemical reactions. He formulated ion transport numbers and the first method for their measurements. He experimented with tubes containing energy rays extending from a negative electrode. These rays produced a fluorescence when they hit the glass walls of the tubes. In 1876 the effect was named "cathode rays" by Eugen Goldstein. Hittorf's early investigations concerned the allotropes of phosphorus and selenium. Between 1853 and 1859 his most important work concerned ion movement caused by electric current. In 1853 Hittorf revealed that some ions traveled more rapidly than others. This observation resulted in the concept of transport number, the fraction of the electric current carried by each ionic species. He measured the changes of the concentration of electrolyzed solutions, computed from these the transport numbers (relative carrying capacities) of many ions, and, in 1869, published his principles governing the migration of ions. He became professor of physics and chemistry for the University of Münster and director of laboratories there from 1879 until 1889. He also investigated the light spectra of gases and vapours, worked on the passage of electricity through gases, and discovered new properties of cathode rays (electron rays). In 1869 he ascertained that the cathode rays glowed different colours because of different gasses and pressures. He noticed that when there was any object placed between the cathode and the illuminating side of the tube, then the shadow of that object appeared. His work resulted in the development of cathode-ray tubes (CRT). The measurement of current in a vacuum tube was an important factor for the development of vacuum tube diodes. CRTs were used as storage devices of the memory of the Manchester Baby computer, the SSEM. He was elected to honorary membership of the Manchester Literary and Philosophical Society in 17 April 1871.

References

Further reading Biographical sketch and reprint of paper on migration of ions

External links Media related to Johann Wilhelm Hittorf at Wikimedia Commons The Cathode Ray Tube site

Illustrations

Worked examples

Example 1 — a first encounter with Johann Wilhelm Hittorf

Start with the simplest possible case. Write down what Johann Wilhelm Hittorf 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 Johann Wilhelm Hittorf 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 Johann Wilhelm Hittorf 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 Johann Wilhelm Hittorf

In research: Johann Wilhelm Hittorf 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 Johann Wilhelm Hittorf 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: Johann Wilhelm Hittorf is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1824 births, 1914 deaths, 19th-century German physicists, so understanding it makes those chapters shorter.
In everyday life: Look for Johann Wilhelm Hittorf 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 Johann Wilhelm Hittorf in 20 minutes

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

Frequently asked questions

What is Johann Wilhelm Hittorf in simple terms?

Why does Johann Wilhelm Hittorf 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 Johann Wilhelm Hittorf?

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 Johann Wilhelm Hittorf.