• Gloria Hoffner

How do fish breath in water?

Science for Seniors - FREE activity - How do fish breath in water? Last week was shark week so now it's time to focus on fish. To be a fish requires gills, bones and a fish bladder. This simple experiment demonstrates how gills work. Materials: Four tissues, scissors and ice tea glass filled with water. Process: Place the four tissue together one on top of the other. Holding one end of the combined tissues, use scissors to cut six inches into the tissues. Show residents the strips of tissue. Then place the tissue cut ends in the water and observe how the tissue ends float. Now remove the tissue ends and observe. Result: Fish gills are represented by the tissues strips turned towards the outside of the fish's body. Your hand represents gill arches which are stiff, boney supports. All fish have at least three gill arches on each side, but some fish have up to seven. Attached to the gill arches are gill filaments, represented by the tissue strips. The filaments are bendable and wave around in the water.

The fish takes in water through its mouth, just like you take in air through your mouth. The air passes over its gills, and blood vessels in the gill arches and filaments take up the oxygen and send it to the rest of the fish's body. Then the water passes out through the other side of the gills.

When you remove the tissue from the water it is one stuck together mess. This lack of movement between the tissue strips represents the fish filaments. They work when floating free in the water and do not work when removed and clumped in a mass outside of the water.

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