Andrea and Carlos' experiment with acids and bases

Dear Ms. Johanson,

Today, we tried to get our cork rocket to launch. First, we put baking soda in the bottom of the plastic bottle. Then we poured lemon juice into the bottle and corked it immediately. We waited and waited and waited, but nothing happened except for a little fizzing.I'm not sure what we did wrong.

We know that lemon juice is an acid and that baking soda is a base. They should have reacted and made the cork pop the way it did during the simulation on the Kitchen Chemistry game from PBS Kids (http://pbskids.org/zoom/games/kitchenchemistry/virtual-start.html). Any advice?

Sincerely,
Carlos and Andrea