My apologies, I said something incorrect. When I said; "The leaves don't spin because they are spinning along with the earth at a constant speed..." I meant to say that the leaves DO spin in accordance to earth's spin, but the earth's constant speed ensures that they do not move.
Just like you and I, we are indeed spinning in space at the same speed earth is spinning, but because earth spins at a constant speed we do not feel it. If the earth suddenly stopped spinning, we would be hurled forwards at nearly 1000 miles an hour, along with buildings, oceans, and much more(think of it like the the train suddenly stopping and pitching you forward).
Earth spins at a constant rate. Think of the last time you rode a subway, train, or public transport. When it began to accelerate, you felt a force pushing you back. You felt this force because the speed is changing. However, after the train reached it's top speed, you stopped feeling this force. This is because both you and the train are moving at the same speed. When the train decelerated, you felt that force again, but in the opposite direction. This is because, once again, the speed of the train is changing, this time negatively. However, if you were to remove a window from the train while it was moving, you would get bombarded with wind and be pushed back.
Earth also has an atmosphere that covers and separates us from the void of space, and holds all of our inert gases down.
Now apply this logic to the leaves on a tree. The leaves don't spin because they are spinning along with the earth at a constant speed (like when you don't feel anything when a train is moving at top speed), and the leaves aren't ripped off the tree because they are protected by an atmosphere (like the window on a train)
Does that explanation make sense to you? Please let me know if I can clarify anything