Light, Vacuum, Speed, and Measurements

In summary, the conversation discusses the misconception that light slows down in air and water because it is believed to only travel at light speed in a vacuum. However, it is explained that light is energy and travels inside of atoms, which means it is always traveling in a vacuum and therefore never slows down. The idea that light slows down in air and water is attributed to incorrect measurements and it is suggested that if the motion of light through these substances were accurately calculated, it would still be traveling at light speed. Ultimately, the conversation concludes that light always travels at light speed, regardless of its surroundings.
  • #1
DeepSeeded
113
1
They say often that light only travels at light speed in a vacuum. That it slows down in air and water. I do not think this is true - correct me if I am wrong as I usualy am :shy:

All atoms are vacuum. Light is energy that is not made of atoms, or in other words it is smaller then atoms if you think of it as a particle.

This light travels inside of atoms. So it is always traveling in a vacuum and therefor never slows down.

I think the measurements are wrong. The light would have many interactions with the atoms that would cause it to take a "bumpy" route to the end of the measuring device. This means that you would read that light travels slower in air or water.

If you were able to find an equation for the motion of the light through air or water and find the line integral for the distance traveled you should find that it is still travling at light speed.

If all these assumptions are true that means that no one should be able to say that light "slows down" in air or water. It should always be traveling at light speed, regardless if it is in vacuum because it is always in vacuum.

This would make things much easier as you always know what speed light is traveling under any circumstances.
 
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  • #2
You need to read the FAQ in the General Physics forum first.

Zz.
 
  • #3
ZapperZ said:
You need to read the FAQ in the General Physics forum first.

Zz.

Wow, that was what I was looking for. Thanks.
 

FAQ: Light, Vacuum, Speed, and Measurements

What is light?

Light is a form of electromagnetic radiation that can be perceived by the human eye. It is made up of particles called photons that travel in waves at a constant speed.

What is a vacuum?

A vacuum is a space that is completely empty of matter. It is created when all the air and particles are removed from a specific area, leaving behind a void.

What is the speed of light?

The speed of light is approximately 299,792,458 meters per second, or about 670 million miles per hour. It is considered the fastest possible speed in the universe and is denoted by the letter "c".

Why is light important in science?

Light is important in science because it helps us understand and study the world around us. It is used in various experiments and technologies, such as telescopes and microscopes, and is also essential for photosynthesis in plants and vision in animals.

What are some common units of measurement for light?

The most common units of measurement for light are nanometers (nm) and meters (m). Nanometers are used to measure the wavelength of light, while meters are used to measure the distance light travels.

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