Though the ukulele and the guitar are in the same musical instrument family, no, the ukulele is not just a small guitar. A ukulele has 4 strings (GCEA) while a guitar has 6 strings (EBGDAE). You will also notice that the fretboard of a ukulele is smaller than of the guitar.
Songs are more playable in a guitar compared in a ukulele because the guitar has richer tones and produces fuller sounds compared to a ukulele. The ukulele always gives off a beachy vibe whenever you play a song as it originated from Hawaii. It is more of a playful yet relaxing musical instrument than a guitar that is more dramatic and dynamic.
Looking at the ukulele and the guitar side by side, they look practically the same; however the ukulele is smaller. The tone and volume of the instrument change with size and construction. The ukulele produces a higher sound than the guitar. It is also easier to play the ukulele. The ukulele is a member of the lute family of instruments.
The ukulele originated in the 19th century as a Hawaiian adaption of the Portuguese machete, a small guitar-like instrument, which was introduced to Hawaii by Portuguese immigrants, mainly from Madeira and the Azones. This instrument gained enormous popularity elsewhere in the United States during the early 20th century and from there spread internationally.