I came up with this idea to make some rockets to launch in the house using stuff we had laying around.

Materials:

8.5 x 11 Paper

Scotch Tape

Scissors

1 Gallon Freezer Bag

Cardboard from a cereal box or heavy card stock

Cardboard tube from Saran wrap or Aluminum foil.

Step 1: Building the Rockets

Roll a piece of 8.5 x 11 paper around the cardboard tube.
Tape the end of the paper to make the rocket body. ( Be sure to NOT roll the paper too tight so that the rocket will slide onto the launcher easily.)
Slide the rocket body off the tube about 1/2" and fold the top over.
Tape the top closed with a couple pieces of scotch tape.
Cut fins out of a cereal box or similar cardboard or cardstock.
Tape the fins to the base of the rocket spacing them evenly.

I decided not to make a nose cone since these are indoor and my kids are 5. Feel free to make a nose cone for your rocket!

Step 2: Building the Launcher

Cut about 1" from the corner of a 1 gallon Ziploc Freezer bag. Freezer bags appear to be a little thicker and more durable. Regular Ziploc bags work also but the freezer bags seem to last longer.
Slide the cardboard tube through the large Ziploc opening and push it through the small hole in the corner and secure with scotch tape. Zip the bag closed.
Hold the tube about 3"-4" from your mouth and blow into the tube to fill the bag. Slide your rocket onto the tube and you are ready to launch.
Hold the base of the tube where it attaches to the bag in one hand and lay the bag on the floor. With your other hand firmly press down on the bag to launch your rocket!