Nuclear and Particle Physics

Previous Topic

Chemistry

Biology

Inicio

Math

Physics

Back to Home

Nuclear and Particle Physics

One of the most fundamental and profound questions that Physics can ask about the Universe around us is:

Is there a basic, elemental unit that constitutes all the matter we are made of?

From the perspective of the history of science, the first attempts to find a possible answer to this question appeared in the field of metaphysics, giving rise to the idea of the atom.

This idea, initially conceived as a purely philosophical concept, finally arrived in the realm of science between 1803 and 1808, during which time John Dalton developed his atomic model using strictly scientific methodologies.

In this model, different types of atoms existed, which were nothing more than simple, perfect spheres that could join together to form molecules and more complex structures. Even so, this simple model allowed us to explain the laws that govern stoichiometry and to understand how different elements combined in chemical reactions.

Quantum Mechanics

However, it was not until the beginning of the 20th century and the birth of quantum mechanics that the mathematical tools and theoretical developments necessary to explain the phenomena that occur at the atomic and subatomic levels became available.

In the modern image provided by these advances, the atom is no longer indivisible, but is understood as a complex system consisting of a central nucleus and electrons distributed around it, forming probability orbitals.

Nuclear Physics

Not only is the atom no longer considered indivisible today, but its central nucleus also has an internal structure made up of protons and neutrons, which in turn are composed of quarks and gluons, the most fundamental subatomic particles known today. The field of physics that studies the atomic nucleus and its properties is called nuclear physics.

To illustrate these ideas, the figure indicates the typical atomic and nuclear size scales, as well as the different disciplines of physics that study each of these scales.

Let's take a ruler marked with millimeters and now divide that millimeter into 10 million equal parts. The resulting length would then be the size of an atom.

The nuclear scale is five orders of magnitude smaller than the atomic scale; that is, the atomic nucleus, which contains the protons and neutrons, is 100,000 times smaller than the total size of the atom.

That is, if we place a millimeter-sized grain of sand in the center of a 100-meter soccer field, the nucleus would be that grain of sand, and the electrons would be in the outermost tiers of the soccer field.

Real-life applications

Nuclear Physics, which began as a basic science, has been naturally incorporated into Applied Physics and Engineering for decades now. In particular, its potential applications to emerging technologies are proving very promising for finding possible solutions to the major challenges facing modern society and humanity.

Current predictions indicate that by 2025, the ocean will contain one ton of plastic for every three tons of fish.

Some nuclear techniques make it possible to measure the movement, fate, and effect of microplastics in the oceans and to study whether they can be separated once ingested by marine animals. Ionizing radiation emitted by atomic nuclei can also be used in plastic recycling.

ITER's tokamak. Prepared to withstand internal temperatures of 150 million degrees Celsius.

Heavy nuclei with a high number of protons and neutrons, such as uranium or plutonium, are used in nuclear fission plants to obtain energy free of CO2 emissions that can contribute to global warming and climate change, although they do generate radioactive waste.

On the other hand, light nuclei such as deuterium, an isotope of hydrogen, or helium can fuse and release large amounts of energy without emitting CO2 or generating radioactive waste. This line of research is what collaborations like ITER are developing to build first-generation nuclear fusion generators.

Manned space travel is becoming an increasingly closer reality. However, in outer space, there is no Earth-like atmosphere to protect spacecraft from solar and cosmic radiation. Although this is not a major obstacle for short-duration missions, radiation becomes a huge problem if we want to live in space indefinitely or travel throughout the Solar System.

For example, on a manned mission to Mars, astronauts would receive significant doses of radiation during spaceflight, which could cause biological damage and even cancer.

For this reason, various space agencies, such as NASA and ESA, have open lines of research in which they apply nuclear physics techniques to design shielding to protect future crews from radiation and also to study the effects of radiation on space travel.

Nuclear Medicine is a medical specialty that uses applications of nuclear physics to diagnose and treat diseases. In the diagnostic field, we find techniques such as computed tomography (CT), magnetic resonance imaging, and positron emission tomography (PET), which aim to study and identify the possible causes of a disease.

On the other hand, in the treatment field, we find techniques such as radiotherapy, which uses high doses of radiation to destroy cancer cells and shrink tumors.

Activity. Answer the following questions.

Remember to review the answers to the open-ended questions at the bottom of this page.

1. What does nuclear physics study?

2. What particles make up the atomic nucleus?

3. What medical application uses radiation to destroy cancer cells?

4. What risk do astronauts face on long missions due to space radiation?

5. What current environmental problem can be addressed with nuclear techniques?

Once you click this button, the questions will close and you will not be able to change your answer.

6. What was the first philosophical idea related to the existence of a fundamental unit of matter?

7. What scientific discipline allowed us to better understand the behavior of atoms and subatomic particles at the beginning of the 20th century?

8. What medical techniques based on nuclear physics are used to diagnose diseases?

9. What is the approximate scale of the size of an atom?

10. What comparison is used in the text to understand the ratio of the atomic nucleus to the entire atom?

Still have questions?

We recommend visiting the following materials for further knowledge or understanding on the topic:

Answers to open-ended questions:

8. Computed Tomography (CT), Nuclear Magnetic Resonance, and Positron Emission Tomography (PET).

10. The nucleus would be like a grain of sand in the center of a soccer field, while the electrons would be in the stands.

2. Brown, M, L., Weidner, & Tilghman, R. (2025, 29 agosto). Physics | Definition, Types, Topics, Importance, & Facts. Encyclopedia Britannica. https://www.britannica.com/science/physics-science/Nuclear-physics https://www.britannica.com/science/physics-science/Nuclear-physics

5. CrashCourse. (2017b, marzo 20). Nuclear Physics: Crash Course Physics #45 [Vídeo]. YouTube. https://www.youtube.com/watch?v=lUhJL7o6_cA https://www.youtube.com/watch?v=lUhJL7o6_cA

6. Arvin Ash. (2023, 10 febrero). ALL nuclear physics explained SIMPLY [Vídeo]. YouTube. https://www.youtube.com/watch?v=m3dpUk1emms https://www.youtube.com/watch?v=m3dpUk1emms

7. The Great Courses. (2018, 15 agosto). Learn about Nuclear Physics, Nuclear Energy, and the Periodic Table of Elements [Vídeo]. YouTube. https://www.youtube.com/watch?v=8h1xWtZ_mI0 https://www.youtube.com/watch?v=8h1xWtZ_mI0