Which plant is going to grow best?

Now that spring has finally arrived, we have been in the planting mood!
Day 1 ( May 2 2013)

Today we decided we were going to try an experiment using bean seeds and different liquids to water them.
During circle we planted our seeds in the exact same way, we placed 3 bean seeds inside of each container using 2 scoops of dirt.
We watered plant 1 with water, plant 2 with orange juice, plant 3 with pop (Pepsi) and the 4th plant we watered with 1% milk.
We then placed them in the window to begin to grow.
As a class we each made a prediction of what we think is going to happen. ( see photo below)
We talked about how we are going to water them every other day.

Day 4