Good Riddles

 
Riddle #20 (easy)

Question: I am weightless, but you can see me. Put me in a bucket, and I'll make it lighter.

What am I?

Riddle #118 (medium)

Question: A shrimping boat is at the docks with a lifeboat hanging off the side 5 meters above the water. If the tides rise at a rate of 1.5 meters per hour, how long would it take for the water to reach the lifeboat.

Riddle #129 (medium)

Question: There are two ropes that both take exactly 1 hour to burn from end to end. You are unable to cut the rope. How can you burn the two ropes in a total of 45 minutes?

Riddle #159 (medium)

Question: Everyday I stalk you all day long,
With every move you make, I never make one wrong.
I vanish twice a day with the sun's height and fall,
I will follow you anywhere,
even the bathroom stall.

What am I?

Riddle #183 (medium)

Question: I plow and plow, but never sow.

What am I?