Scales protect the fish from its environment. They overlap like shingles on a roof so that the skin of the fish is not exposed. As a fish grows, their scales produce rings much like a tree-and that is one way scientists can tell how old a fish is.Most fish get extra protection from a layer of slime that covers their scales. This slime helps them move through the water better, and keeps pests off of the fish skin.s a fish grows, their scales produce rings much like a tree-and that is one way scientists can tell how old a fish is. Most fish get extra protection from a layer of slime that covers their scales. This slime helps them move through the water better, and keeps pests off of the fish skin.
Inside a Muffler. Located inside the muffler is a set of tubes. These tubes are designed to create reflected waves that interfere with each other or cancel each other out. Take a look at the inside of this muffler: The exhaust gases and the sound waves enter through the center tube.
Most do-it-yourselfers can do a few basic muffler repairs , but muffler replacement requires stronger mechanical skills. A how-to video demonstrates what is involved. An after-market muffler can cost $30-$200 or more, depending on the make and model of vehicle. A CostHelper reader in California reports paying $46 for a do-it-yourself muffler installation.