Another way dishwashers are made quieter is by cycling the water in between the middle / upper spray arm and the middle / lower spray arms. Cycling the water between the upper and lower zones allows the machine to run a little quieter. Most dishwasher decibel ratings are around 56 decibels. Itâs tough to imagine what that sounds like if youâve never known what to listen for. There are many different comparisons- imagine something like a gentle breeze through tall trees. My parents have a 56 decibel rated Bosch.
Mirages occur when there is a rapid shift in air density in the atmosphere -- when the air at one level is a lot hotter than the air at an adjoining level (check out this page to find out why hot air is less dense than cold air).
The large cavity of the eye is filled with a jelly like substance called vitreous. When we are born it is attached to the back surface of the eye, the retina. As we age the vitreous shrinks. So at some point it has to separate from the retina. This can irritate the retina and cause flashing lights. It can also result in floating spots in our vision. This is because the vitreous surface that was against the retina is now floating in the center of the eye casting a shadow. Most of the time (99+%) this does not cause a problem.