Materials Needed

1. 2 Soda Bottles (2L)
2. Construction Paper
3. Tennis Ball
4. String (yarn or something that is durable)
5. Large Garbage Bag
6. Shoe Box (tough, preferably cardboard)
7. Scissors
8. Tape
9. Glue Gun
10. Water
11. **Baby Powder (picture 1)

Step 1:

clean out your soda bottles. And cut off the bottom and top ends of ONE (picture 2).

Step 2:

putting aside the bottles… take a shoebox and, with your scissors, fashion 3 even triangles/ diamond shaped, wings for your rocket

Step 3:

Glue the wings onto the main bottle & body of your rocket **note: it will be easier and more durable to glue the wings onto a straight solid strip of cardboard before the body (picture 4) Glue wings and ½ a bottle onto your main body (picture 5)

Step 4:

Setting the rocket aside, start designing a parachute for your tennis ball. Using the garbage bag cut a large, even shape into the bag

Step 5:

Take your string and place several strips evenly around the perimeter of the circle

Step 6:

Make a harness for your tennis ball with the string. Strategically glue the parachute and tennis ball together

Step 7:

Make an aerodynamic cone for the top of your rocket using construction paper OR another soda bottle. Make sure this cone can fall off when the time comes for the parachute to be released

Step 8:

for extra insurance, apply a bit of baby powder onto the parachute. Place the tennis ball and parachute inside the top, cut, portion of the rocket. Make sure that the parachute is not packet tight or else it will not release when the time comes

Step 9:

fill up soda bottle ½ of the way with water and shoot!

Step 10:

Modifications:
o Change cone head to plastic, more aerodynamic
o Created more of a body using another soda bottleo Use 2 wings instead of 3
o Make parachute larger, using a black bago The best way to maximize the trajectory is to launch your water bottle rocket at a 45-degree angle. This will give you the maximum range.
o When you pack the parachute, don't roll the lines around the parachute. Fold the parachute until it fits where it need to, and gently accordion-fold the lines. make the parachute open faster.

Step 11:

The Physics:
Rocket: Air is pumped into the bottle rocket to pressurize the bottle and thrust is generated. When the string is pulled, water shoots out propelling the rocket to great heights because the weight of the bottle rocket is constantly decreasing. As the water leaves the rocket, the volume occupied by the pressurized air increases.

Parachute: The amount of air resistance (as explained by Newton’s second law of motion) depends upon the mass of an object. In the case of our tennis ball, this object will have more acceleration until the parachute is released and it encounters air resistance equal to its weight.