Water Bottle Rockets

Our rocket consisted of one 2 liter bottle, a funnel as a cone, a circle parachute that was hidden under the cone attached by four long strings,  a ball of clay under the cone, a small glass circle over the clay and 4 small fins on the sides of our bottle. The creation of our bottle rocket took a lot of time, thought and failure to come up with.

Our first creation was only a bottle with a small plastic bag as its parachute attached with tape. The next day we added in a big garbage bag as the parachute and attached it with four short strings. We tested this model on a balcony and decided we should change it a little. We read on the internet to cut the parachute into a big circle and attach it with four short strings, so thats what we did then we put a cone over the parachute. We also read that it was a good idea to add fins so we  hot glued and duct taped in triangle shaped 5 by 1.5 inch styrofoam project board fins. We knew we had to add a mass to the cone, and one site said to add clay. We grabbed a ball of clay from the clayroom and stuffed it in the tip of the cone. Then we went down to the field to launch.

For our first and second trial we used the same amount of water, about 1/3 of the bottle. On our first trial our rocket stayed up for 5.59 seconds, but the parachute didn't work so we tried again, we added in a small glass circle to cover the clay in our cone. We did this because we thought the parachute was sticking to the clay so we put that in so it hopefully wouldn't stick.  On our second trial our rocket stayed up for 6.71 seconds, but still our parachute was not working.

 Mr. Blake suggested we make the strings of our parachute longer, so we traveled up to the classroom and changed the length of the strings. We came back down for our final trial and filled the bottle up 1/2 with water. We pumped up the rocket a lot, build a lot of pressure and on this final trial our rocket stayed in the air for 11. 87 seconds. Yay the longest yet and past 10 seconds! The rocket went up high and our parachute kicked in about 15 ft from the ground. We were happy with 11.87 seconds so we didn't change anything and we hope that tomorrow our rocket will do 11. 87 seconds again.