The way that light waves interact with different mediums is called the

when light bounces off an object.

when u place something in water the light refracts the object in the water.

transparent

3 to 6 ours after eating.

transparent

translucent

opaque

it really depends on what you want the most from your concert experience. i've been first and second row at sold out concerts and while the view of the band was amazing, being crushed against the barrier was not. and when there isn't anyone in front of you, it's hard to dance and you don't really get to experience the energy of being in the middle of the crowd. also earplugs are a must.

being towards the middle can also be fun and the energy is great. i'm very short so the view isn't that great, but it can be a great experience. however when i've been in the middle i've had several mosh pits start right next to me that i've had to escape from, so beware.

having seating at a concert   is an entirely different experience from being on the floor. the view is better than the middle of the floor but definitely not as good as being center of the front row. it's definitely nice to be able to sit between sets and have your spot reserved so you don't even have to be hours early. if you don't like getting squished up against drunk and sweaty strangers then seating is perfect for you. the energy of the seating is a little more subdued, but it's still a good experience.    

explanation:

there are so many examples for that in different areas, like biology experiment carried out in our lab recently.

here's one link: