When i do count the clock that tells the time why is this verse an example of iambic pentameter

Because the words in this verse are all short and unstressed as well as only consisting on one or two syllables. In an iambic pentameter there will be a few short syllabled and simple words followed by a longer and more stressed word. Therefore this verse is an example of an iambic pentameter because all of the words in it are short and simple.