by Cygnetta » Sat Jul 30, 2022 3:24 am
So in school you may have learned that a white object reflects all light wavelengths. A mirror also reflects all light, so what makes them different? I never thought to ask this until when I learned about it recently. Turns out that white paper has a molecular structure that allows light to penetrate it slightly and bounce around at different angles before being reflected back at many different angles. In contrast a mirror mostly reflects light at certain specific angles, which is why it can give you back a certain image. Also, in reality nothing reflects all light, just most light.
The double slit experiment is one of the coolest phenomena out there involving light. The experimenter creates an apparatus with two slits so that photons have an equal chance of passing through either. They control the setup so that only one photon can pass through at a time. After passing through, there is a screen that the photons will hit to show “where” they passed through. The weird thing is that when they have allowed several photons to pass through one after the other, instead of there being some dots on the left and some on the right, like if you did the experiment with tennis balls, there will be a pattern that resembles a wave, with alternating sections of intensity, as if you did the experiment with ripples in water. Scientists call this property of light wave-particle duality because light can behave as a wave or particles depending on the situation.
The experiment gets even weirder when you decided to measure exactly which slit each photon passes through. If you set up an observation device that gives data on which slit a photon passed through, all of a sudden the light is forced to behave like particles, and you will get the tennis ball effect. However (this is the weirdest part), if you set up the device and then secretly erase its data, you will get the wave effect. This means that the light chose to behave differently based on whether we could observe it as particles or not, AFTER it already passed through the slits.
For the record, I do not believe in Schrödinger’s cat. This is an hypothetical experiment where you set up an apparatus that reads a quantum event with a 50% chance of happening. If it happens, the device kills the cat on the room. Since scientists have found that quantum events rely on observation to actualize, it is said that before being observed the cat will be both dead and alive. The reason this won’t work in real life is because the cat itself is an observer. At the point where the cat is killed or not, it will observe that itself, so it can’t be both dead and alive. A better option would be to use a rock for the thought experiment. Maybe if the quantum event happens, the rock falls off the table. It may be that the rock would be both on the table or off the table. However, even this is doubtful to me. A bug, or even potentially bacteria, could be observers. If there were truly no observers in the room and the rock was prevented from altering the outside environment that might be perceived by observers, such as making vibrations if it fell, then this could happen. But something as dramatic and unintuitive as a both dead and alive cat cannot happen.