F.4-F.5________Biology

procedure

1~Fill a small gas jar with water and invert it over a trough of water.
2~Breathe out most of the air from your lungs,and then breathe out some more air through the rubber tubing into the gas jar containing water .Repeat this step until the gas jar is completely filled with exhaled air.
3~Use a glass plate to cover the open end of the gas jar,and stand it upright on the bench

small gas jar
rubber tubing ---breathe out air(blow)
　　　┬─┬ 　↗
├ 　　│　│　↗ 　┤
│ 　　│　│↗ 　 │
├ 　　 ↖ ↗ 　　　┤jar containing water
└──┴─┴───┘