An "iamb" is a word or set of words that goes 'da-DAH', like "my KNEE", or "your FACE", or "his DOG", or "come HERE".
Many poems have the same rhythm (beat) in each line, and there are different rhythms they can have. I can show you that, if I take a poem you know, and recite it first with the correct beat, and then with the wrong beat.
Here's the correct beat: MAH-ree HAD a LIT-tle LAMB its FLEECE was WHITE as SNOW.
For the wrong beat, let's use 'iambs' like I explained up above: ma-REE had A lit-TLE lamb ITS fleece WAS white AS snow.
If a poem is in the rhythm of "iambic tetrameter", then each line is made out iambs, and there are 4 of them ("tetra") in each line.
Now I have to try and find an example for you. Thank you very much.
I'll make one up. Remember, an iamb goes 'da-DAH":
my DOG came IN-to SCHOOL one DAY and CHASED the HAM-sters ALL a-ROUND. the PRIN-ci-PLE came IN-to CLASS and TOOK my DOG down TO the POUND.
