The hardest part about understanding the quantum world is to realize that it hasn't any physical space which we have to physically travel through in order to get from A to B. Travel through the quantum world is all about possibilities . On the surface , this doesn't seem to be such a big deal , but from our real world perspective it is a big deal . Take the famous double slit experiment for an example . If you shoot light ( photons ) through each slit at the same time you will get a series of dark and light lines on a screen which is behind the slits . This is because the photons going through each slit have a wave component and the photon waves going through each slit are in phase or slightly out of phase creating an overlap which we see in our world as light and dark lines . If the photon waves are in phase it is a light line and if they are out of phase it is a dark line. The photons going through the slits are traveling through a quantum world to reach the screen but we don't notice that phenomena from our perspective because of the volume of photons . Let's reduce the photons going toward the slits to one photon every 3 seconds . We still get the same light and dark lines . This happens because the photon travels through the quantum world and although the quantum world hasn't any space to travel through , it does have possibilities or potential outcomes. These potential outcomes or possibilities are equivalent to you choosing the direction you want to travel in our 3 dimensional space .
The photon has these three ( 3 ) possibilities:
1. Goes through slit number 1 .
2. Goes through slit number 2.
3. Misses both slits because nothing is 100 %.
Similarly the photon wave has three possibilities:
1. Goes through both slits.
2. Goes through either slit 1 or 2.
3. Interferes with itself on the screen ( both slits ) or doesn't interfere with itself ( one slit ) .
Here's the most interesting part . The photon wave exists in all its' possibilities . We come along to observe or measure . Our observing or measuring action causes all the quantum possibilities to adjust so that only one possibility remains in our real world .