Can radio waves pass through walls while visible light cannot?

  • Thread starter Jodo Kast
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In summary, photons have the ability to penetrate materials and can be detected by humans in more ways than just visible light. For example, our bodies can detect x-rays, but we cannot form an x-ray map of our surroundings without the help of computers. If our eyes were only able to detect x-rays, we would not be able to see the sun inside a building without artificial x-ray sources. Radio waves, which have less energy than light waves, are able to pass through materials that absorb and reflect visible light. However, radio waves are not made of photons like visible light, but are still considered part of the electromagnetic spectrum. Both radio and visible light are different ends of a continuous range of phenomena, just like a pile of sand and a
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Jodo Kast
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I couldn't sleep the other night because I was thinking about photons and their ability to penetrate materials. It can be argued that humans are photon detectors. This is true in more than just the sense of visible light because photons don't just enter our pupils. As an example, our bodies can detect x-rays (our bones stop them). But we can't form an x-ray map of our surroundings, as we can with visible light, unless computers assist us.

Imagine for a moment if our eyes were unable to detect visible light. For some reason we evolved to detect x-rays. If I were in a building, away from all windows, what would I see? Assume that all light sources (in this case the sources would emit x-rays) were turned off. Since x-rays have greater penetrating power than visible light, would I still see the Sun if I were inside a building? If one had eyes able to detect x-rays would there be a need to make artificial x-ray sources?

But then I thought about much longer wavelengths. As you know, if you step outside of a building and shine a flashlight against the wall, the photons will not pass through the wall and be detected by any humans inside. Interestingly, I asked, "Why can radio waves pass through the wall?"

Since radio waves have less energy than light waves, how are they able to penetrate materials that absorb and reflect visible light? I used to think that radio waves were made of photons, but I read recently that they are not. It just seems logical to assume that the carriers of electromagnetic radiation, the photons, waved at all wavelengths.

Since radio waves are not made of photons (are they made of electrons?) why are they put on the same chart as visible light, ultraviolet, x-ray, gamma-ray, etc.?
 
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Radio and Visible light are exactly the same phenomenon.

Long radio waves can be explained "classically" because the wavelength is so much larger than the size of atoms, and because they have low energy: you have many many many individual photons each very subtle so you only see the overall effect. The atoms of the radio antenna don't stop and absorb a photon and change state; instead, quantum effects mix displacements of the free electrons with the photons and when it all comes out in the end you say "electric field" etc.

Short visible waves don't do all that because they are very small compared to the atoms. Your eyes work by having a molecule stop (absorb) photons which causes a change to the electron's energy level in the atom. Visible light's energy is a good match for the available energy levels in organic molecules... so no coincidence that we use it to see with!

Just at the edge of visibility and into UV, individual photons knock individual electrons out of a metal, which is what lead to the realization that photons exist. Radio waves, in huge numbers, gently sway the electrons in the metal instead, like water molecules in the surf making small seashells dance on the edge of the beach.

The two things are extreme ends of a continuous range of phenomena. Just like water is "a liquid" in bulk, but individual hard and solid atoms on another scale. Radio and Visible light is like the difference between a pile of sand and a large slab of stone. Different things happen if you drop each one onto you.

--John
 

1. What are penetration perturbances?

Penetration perturbances are disruptions or disturbances that occur during the process of penetration, where one object or substance enters another. This can happen in various scientific fields such as material science, biology, and physics.

2. How do penetration perturbances affect materials?

Penetration perturbances can cause changes in the physical properties of materials, such as their strength or structure. They can also lead to the formation of defects or cracks, which can compromise the integrity of the material.

3. What are some common causes of penetration perturbances?

Some common causes of penetration perturbances include impact or collisions, chemical reactions, and changes in temperature or pressure. They can also be caused by external forces, such as mechanical stress or vibrations.

4. How are penetration perturbances studied in scientific research?

Scientists use a variety of techniques to study penetration perturbances, including microscopy, spectroscopy, and computer simulations. These methods allow researchers to observe and analyze the behavior and effects of penetration perturbances on different materials.

5. Can penetration perturbances be prevented or controlled?

In some cases, penetration perturbances can be prevented by using protective coatings or designing materials with specific properties. However, they cannot always be completely avoided. Researchers are constantly studying ways to control or minimize the effects of penetration perturbances on materials.

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