Does light need particles to move?

Answer 1

Light is the visible form of electromagnetic radiation. All the forms of electromagnetic radiation travel at the speed of light, when they are traveling through a vacuum. A vacuum is a space which contains no particles. The space between the sun and the earth is mostly empty space. When light makes contact with a particle, the light interacts with the atoms of the particle. In chemistry, we learn how electrons interact with light. Visible light is composed of many colors. Each color has a specific frequency.

Energy = Plank's constant * frequency

This means each color of light has a specific amount of energy.

Before the electrons absorbed the energy, the electrons are in their "ground" state. This is their most stable state. When electrons absorb a specific amount of energy, we say that the electrons are in their "excited" state. This is an unstable state. To become stable energy is released, and we see a specific light of a specific color. When you see a blue shirt, you are seeing the result of electrons releasing a specific amount of electromagnetic energy, in the form of blue light.

What happened to the other colors in the visible light?

The atoms absorb the rest of the energy. This causes the atoms to vibrate at a higher frequency. Now the atoms have more kinetic energy. Temperature measures the average kinetic energy of the atoms. So the temperature of the shirt is increasing. When sun light shines on a blue shirt, the temperature of the shirt increases.

You may be wondering what all this has to do with your question!

The energy of electron is called orbital energy. The energy of the vibrating atom is called kinetic energy. The light's energy was converted into orbital energy and kinetic energy. During this time, the light does not exist. When the blue light is emitted from the atoms, light does exist. During this process, the form of a specific amount of the energy is changing from white light to orbital energy to blue light. The rest of the energy is in the form of vibrational kinetic energy of the atoms. This form of energy is actually what we call heat energy.

Average velocity = distance ÷ time

Since the light did not exist for a specific amount of time, but the clock kept on ticking, the average velocity of the light is less than the speed of light in a vacuum.

Light does not need particles to travel. But the particles need the energy of the light to be seen by us and to experience some heat energy.

Answer 2

Light can behave as a wave or a particle (photon). In a vacuum, light can move without needing particles, as it propagates as an electromagnetic wave. However, in a medium like air or water, the interaction between light and the medium involves particles.