I am a beginner tap dancer and learning music. I don't understand the difference between swing rhythm and straight rhythm. Can someone elaborate the difference?
We walk in straight rhythm and skip in swing rhythm.
When we walk the sound of our feet goes:
LEFT (wait) RIGHT (wait) LEFT (wait) RIGHT (wait)
The 'waits' get shorter when we walk more quickly.
When we skip (I mean without a rope) our feet go:
LEFT (wait) left RIGHT (wait) right LEFT (wait) left RIGHT (wait) right
I've written the loudest sounds in upper case: LEFT and RIGHT. In music these are the beats. The lower case 'left' and 'right' are on the toes, so they sound quieter.
It is possible to leave out the 'waits' and go:
LEFT left RIGHT right
— but that wouldn't properly be described as skipping because the sound is too regular; too straight. (In dance I think it's called 'step-hop'.) Skipping has a characteristic uneven rhythm. In music we say the beat is in three, or divided in three, or 'swung'.
If you say the following lines/verses out loud and quite quickly, I think you'll be able to tell which ones divide the beat into two or four (and are therefore straight), or into three (and are therefore swung).
John had Great Big Waterproof Boots on; John had a Great Big Waterproof Hat Put 'em together and what have you got? Bibbidi-bobbidi-boo Dirty British coaster with a salt-caked smoke stack, Butting through the Channel in the mad March days, The wonderful Wizard of OZ Ernest was an elephant, a great big fellow, Leonard was a lion with a six-foot tail, George was a goat, and his beard was yellow, And James was a very small snail. James James Morrison Morrison Weatherby George Dupree What is the matter with Mary Jane? I've promised her sweets and a ride in the train, The Alderney Said sleepily: "You'd better tell His Majesty That many people nowadays Like marmalade Instead." They're changing guard at Buckingham Palace
In "straight" rhythm, notes which last a half beat are of equal time value: that is, they divide the beat evenly in half. In "swing" rhythm, those same notes are played unequally, with the first a bit longer and the second a bit shorter.
A John Philip Sousa March is the perfect example of straight rhythm.
Contrast that with the rhythm in this Nat King Cole recording of Sweet Lorraine.
"Swing" is often interpreted as follows
play two consecutive notes as if they were a dotted triplet, so count (1, 2) as (1, 2, 3) and tie the 1 and 2 together.
By counting (1, 2) as (1, 2, 3) this has to fit into the same overall time. So 4/4 might get counted as 6, using quarter note triplets each half note is a group (1, 2, 3) and the swing groove is (1+2, 3) a long followed by a short beat.
Straight rhythm is exactly as quoted. Every pulse or beat is exactly the same length as every other.
Swing is rather different. I use 'the Humpty Dumpty' rhythm concept with students. I suppose 'Frere Jacques' would be appropriate for the straight rhythm. By saying each of these, the idea of how they differ should be apparent.
Assuming a pair of notes written as the same duration, a "straight" rhythm plays the two notes as equal duration, as written. While a "swing" rhythm holds the first note for a bit longer and the second a bit shorter. If you have a metronome playing at the same tempo as you trigger the notes, the first note of each pair will line up with the metronome while the second one is slightly delayed. How much delay varies from 'soft' or mild to 'hard' swing, it's a matter of style and taste.
A Youtube video demonstrating the difference for jazz. The concept of swing is the same for other genres.
Wikipedia has more detail.