Log In Start studying!

Select your language

Suggested languages for you:
StudySmarter - The all-in-one study app.
4.8 • +11k Ratings
More than 3 Million Downloads
Free
|
|

Turning Points in Physics

Want to get better grades?

Nope, I’m not ready yet

Get free, full access to:

  • Flashcards
  • Notes
  • Explanations
  • Study Planner
  • Textbook solutions
Turning Points in Physics

A turning point in physics is when a scientist made a revolutionary discovery or development that affected physics so that many things accepted before the discovery were then seen as incorrect or uncertain. Learning about turning points is essential to see how physics has changed and to appreciate science from a historical viewpoint.

What are the turning points in physics?

Turning points in physics include the discovery of the electron, wave-particle duality, and special relativity. All three turning points have left a big mark on both physics and science in general.

Discovery of the electron

During the 1880s and 90s, scientists searched cathode rays for the carrier of charge in matter. Their efforts resulted in the discovery of the electron by J. J. Thomson in 1897. Thomson directed the cathode rays through two parallel metal plates to the glass end of a tube. The rays went down when the upper aluminium plate was negative and up when it was positive. The deflection reflected the potential difference between the plates. Cathode rays were clearly negatively charged particles based on magnetic and electric deflections. Thomson discovered the granularity of electricity, which explains how individual particles carry a charge.

  • The idea of a homogenous atom particle was disproved.

  • The existence of subatomic particles was proved.

  • Daltons atomic theory assumption that atoms were indivisible was disproved.

Wave-particle duality

Wave-particle duality was born from the work of many scientists such as Max Planck, Albert Einstein, Louis de Broglie, Erwin Schrödinger, Niels Bohr, and Arthur Compton. In quantum physics, wave-particle duality states that each particle or quantum phenomenon may be represented as a particle or a wave. This theory gave rise to major discoveries, such as:

  • A differential equation that describes how a wave function can explain all aspects of the behaviour of light and matter.
  • The recognition that light and matter have characteristics that are both wave-like and particle-like.

Special relativity

In 1905, Albert Einstein developed the theory of special relativity. However, the idea of relativity did not begin with him, as Galileo and Newton had been exploring relativity for centuries. The concept of relativity expresses the realisation that the laws of physics depend on the observer.

For example, if you fly into space at nearly the speed of light, time runs more slowly on your spacecraft than it does on the earth. So when you return to the earth, you will find that your friends have grown older than you have.

It is possible to divide modern relativity into two theories, special relativity and general relativity. The theory of special relativity is important because:

  • It states that the laws of physics are the same and can be stated in their simplest form in all inertial frames of reference.
  • It states that the speed of light (c ) is constant and independent of the relative motion of the source.
  • An outcome of this theory is the famous equation: E = mc².

Einstein is well-known because his theories of relativity made ground-breaking predictions that came to fruition in the real world. Most significantly, his hypotheses have been proven to have been highly precise in a wide range of experiments, forever transforming our understanding of space and time.

Turning points in physics. Albert Einstein. StudySmarterAlbert Einstein

How did turning points in physics influence science?

Turning points in physics have provided fundamental knowledge that has led to further discoveries and influenced technology in many ways. Examples include:

  • The discovery of the electron, which brought in a new era in physical science, thus paving the way for modern ideas of atomic structure and chemistry.

  • Wave-particle duality, which highlighted the inability of classical terms such as particle and wave to explain quantum-scale object behaviour.

  • Special relativity theory, which has had a significant influence on physics, particularly in the computation and comprehension of high-velocity events. As a result, we now have a far better grasp of space and time than we did at the start of the century.

Turning Points in Physics - Key takeaways

  • A turning point in physics is when a scientist made a revolutionary discovery or development that affected all subsequent understanding.
  • Three main turning points in physics were the discovery of the electron, wave-particle duality, and special relativity.
  • The discovery of the electron disproved the idea of a homogeneous and indivisible atom by discovering subatomic particles.
  • Wave-particle duality helped develop the model of the atom by recognising that an electron possesses particle and wave-like properties.
  • Special relativity has had a big impact on the calculation and understanding of high-velocity phenomena as well as on our understanding of space and time.

Frequently Asked Questions about Turning Points in Physics

A turning point in physics is when a scientist makes a new discovery or development that has such an impact on physics that many previously held beliefs are now considered incorrect or questionable.

The three main turning points in physics are the discovery of the electron, wave-particle duality, and special relativity.

The turning points in physics are important because they formed the fundamentals of physics and opened new ways of understanding for many later discoveries to come.

Final Turning Points in Physics Quiz

Question

Who discovered the electron?

Show answer

Answer

J. J. Thomson.

Show question

Question

When was the electron discovered?

Show answer

Answer

In 1897.

Show question

Question

Were cathode ray tubes used in the discovery of the electron?


Show answer

Answer

Yes, they were.

Show question

Question

What was the first subatomic particle that was discovered?


Show answer

Answer

Electron.

Show question

Question

Did the discovery of the electron disprove the idea of an indivisible atom?

Show answer

Answer

Yes, it did.

Show question

Question

Who proposed the theory of special relativity?

Show answer

Answer

 Albert Einstein.

Show question

Question

When was the theory of special relativity developed?


Show answer

Answer

In 1905.

Show question

Question

Which famous equation was provided by special relativity?


Show answer

Answer

E = mc².

Show question

Question

Who proposed wave-particle duality?


Show answer

Answer

Louis de Broglie.

Show question

Question

When was wave-particle duality proposed?


Show answer

Answer

In 1923.

Show question

Question

Which scientists studied wave-particle duality?


Show answer

Answer

Max Planck, Albert Einstein, Louis de Broglie, Erwin Schrödinger, Niels Bohr, and Arthur Compton.

Show question

Question

What are the two parts of modern relativity? 


Show answer

Answer

The theory of special relativity and the theory of general relativity.

Show question

Question

What disproved the idea of a homogenous atom particle? 


Show answer

Answer

The discovery of the electron.

Show question

Question

Do light and matter have characteristics that are both wave-like and particle-like?


Show answer

Answer

Yes, they do.

Show question

Question

Can you name the symbol for the speed of light?

Show answer

Answer

 It is c.

Show question

Question

Who discovered the granularity of electricity?


Show answer

Answer

J. J. Thomson.

Show question

Question

Who was exploring relativity centuries before Einstein?


Show answer

Answer

Galileo and Newton.

Show question

Question

Which of these discoveries was the most important one for our understanding of space and time?


Show answer

Answer

Special relativity.

Show question

Question

Did wave-particle duality help to develop the model of the atom?

Show answer

Answer

Yes, it did.

Show question

Question

According to Einstein, is time relative?


Show answer

Answer

Yes, it is.

Show question

Question

Did the plum pudding model say atoms have a neutral total charge?

Show answer

Answer

Yes, it did.

Show question

Question

Were cathode-ray tubes used in Thomson's experiment?


Show answer

Answer

Yes

Show question

Question

What is the concept of the plum pudding model?


Show answer

Answer

 Negative particles are floating around in a positively charged soup in an atom.

Show question

Question

Who did the gold foil experiment?


Show answer

Answer

Ernest Rutherford.

Show question

Question

When did the gold foil experiment take place?


Show answer

Answer

 In 1909.

Show question

Question

What was the big discovery of the gold foil experiment?


Show answer

Answer

 The nucleus

Show question

Question

Does the nucleus contain the bulk of the atomic mass?


Show answer

Answer

Yes, it does.

Show question

Question

Who did the oil drop experiment?


Show answer

Answer

Robert Millikan.

Show question

Question

Were electrons the first subatomic particles that were discovered?


Show answer

Answer

Yes, they were.

Show question

Question

Was Thomson able to determine the charge of the electron in relation to its mass?

Show answer

Answer

 Yes.

Show question

Question

What else did Thomson study?

Show answer

Answer

Positively charged particles in neon gas.

Show question

Question

 In the plum pudding model, what were the raisins representing?


Show answer

Answer

Electrons

Show question

Question

In the plum pudding model, what was the dough representing?

Show answer

Answer

Positive charge

Show question

Question

What was Rutherford looking for in his experiment?


Show answer

Answer

Alpha particles with high deflection angles.

Show question

Question

When did the Millikan oil-drop experiment take place?


Show answer

Answer

In 1909.

Show question

Question

What was the big discovery of the oil-drop experiment?


Show answer

Answer

 First precise direct measurement of a single electron's charge.

Show question

Question

Can the charge on a drop be calculated using the balance of gravity and electric forces?


Show answer

Answer

Yes, it can.

Show question

Question

The charge of an electron discovered may be quantised in units of what?


Show answer

Answer

1.602176634 × 10 ^−19 coulomb.

Show question

Question

Which of the following is not one of the three big steps that helped understand electrons better?


Show answer

Answer

Michelson-Morley experiment

Show question

Question

 Who proposed the theory of special relativity?

Show answer

Answer

 Albert Einstein.

Show question

Question

When was the theory of special relativity conceived?


Show answer

Answer

 In 1905.

Show question

Question

What is Einstein's first postulate regarding the theory of special relativity about?


Show answer

Answer

Reference frames.

Show question

Question

What is Einstein's second postulate regarding the theory of special relativity about?


Show answer

Answer

The speed of light.

Show question

Question

In which context are all laws of physics the same to any observer?


Show answer

Answer

In an inertial frame of reference.

Show question

Question

The speed of light in a vacuum is constant. Is the speed of light in matter lower or higher?

Show answer

Answer

It is lower than c.

Show question

Question

What is the speed of light (c) in a vacuum?


Show answer

Answer

It is 3.00 * 10 ^ 8 m / s.

Show question

Question

What was the aim of the Michelson-Morley experiment?


Show answer

Answer

Comparing the speed of light in different directions to detect the relative motion.

Show question

Question

 Which famous equation was provided by the theory of special relativity?


Show answer

Answer

E = mc ^ 2.

Show question

Question

 Which year was the Michelson-Morley experiment conducted?


Show answer

Answer

1887.

Show question

Question

In which circumstances is length contraction possible?


Show answer

Answer

In relativistic speeds.

Show question

60%

of the users don't pass the Turning Points in Physics quiz! Will you pass the quiz?

Start Quiz

Discover the right content for your subjects

No need to cheat if you have everything you need to succeed! Packed into one app!

Study Plan

Be perfectly prepared on time with an individual plan.

Quizzes

Test your knowledge with gamified quizzes.

Flashcards

Create and find flashcards in record time.

Notes

Create beautiful notes faster than ever before.

Study Sets

Have all your study materials in one place.

Documents

Upload unlimited documents and save them online.

Study Analytics

Identify your study strength and weaknesses.

Weekly Goals

Set individual study goals and earn points reaching them.

Smart Reminders

Stop procrastinating with our study reminders.

Rewards

Earn points, unlock badges and level up while studying.

Magic Marker

Create flashcards in notes completely automatically.

Smart Formatting

Create the most beautiful study materials using our templates.

Sign up to highlight and take notes. It’s 100% free.

Get FREE ACCESS to all of our study material, tailor-made!

Over 10 million students from across the world are already learning smarter.

Get Started for Free
Illustration