So we have to attach our source of propulsion and that is the two-liter bottle. A simple piece of duct tape along with the PVC pipe inserted into the mouth of the bottle affixed snugly will do the trick and now our rocket launcher is ready to go. Whenever you engage in any sort of science or engineering project be sure to follow proper safety procedures so no one gets hurt. To get ready to launch your rocket go ahead and put it on the launch tube and then you're going to stomp on the two-liter bottle. To do so stomp perpendicular to the long axis of the bottle. Don't go parallel to the long axis because that'll blow your bottle out. And then stomp! In order to easily re-inflate the bottle place your hand over the PVC pipe blow and now your bottle is reinflated. You can use these bottles over and over again for dozens of times as long as you're careful with them. To calculate how high the rocket flies start by having students stand at two locations a measured distance away from the rocket. When the rocket launches students will use altitude trackers to follow the rocket to its highest point. Hold the tracker in place and have another student make note of the angle indicated by the string. Record these measurements on the data log sheet. Having multiple students at each measurement location provides more data points and give students a more accurate average angle of elevation to use when calculating the height of the rocket. To make the altitude tracker you'll need the altitude tracker template, a stapler, some tape, a piece of string, scissors, a paper clip and a penny or some other sort of weight. Start by cutting the template out following the solid lines on the outside of the altitude tracker. Take the line of Bs and the line of As and connect them. You're going to roll the B past the A. And then it says to staple. My stapler does not fit inside of there. I am going to simply tape it. The idea is to make a sighting tube. At the corner of this protractor, there's a little black dot. You need to poke a hole in that little black dot using your paper clip. And then we're going to stick our string through that hole. If you need to make your hole little bit bigger for your string use a pencil. Just open it up a little bit. Feed the end of the string through the hole and secure it to the back of your altitude tracker with a piece of tape. You're gonna need a little bit of weight on that string and that's where our penny comes in. Just tape your penny to the bottom of the string. So now you have an altitude tracker that can be used to sight your rocket and measure the angle of elevation. In order to calculate the altitude that your rocket achieves at its apex you'll need a few tools. You'll need a protractor, a piece of graph paper, a ruler with metric measure, and something to write with. You'll also need to obtain your average angle of elevation from Baseline A and baseline B. Those are available on the long sheet that we used in the field. I'm going to say one millimeter is equal to 1 meter, so if it was a hundred meters long our baseline it'll be a ten-centimeter line on our model. Now I'm going to construct my angles. We had tracking station A and tracking station B. I look on the log sheet and I see that tracking station A the average angle of inclination was 32 degrees, so I'm going to construct the angle - 32 degrees - and draw the line from tracking station A through that angle: 32 degrees. Tracking station B the average there was 55 degrees so I construct from tracking station be a 55 degree angle and do the same thing - extend the line from tracking station B. And this is where your rocket was. Now you have calculated the altitude that your rocket achieved from the viewing level of your observers eyes. If you want to calculate the entire altitude you'll need to measure eye-level of your observers, find the average and add that distance to your calculated altitude. Now these paper rockets are not going to go to Mars, but someday the students building these rockets could be engineers and scientists working on a mission that is part of the Journey to Mars and beyond.