Water Bottle Rockets Essay


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A H2O bottle projectile is basically that ; a bottle modified in the image of a projectile so filled with a choice sum of H2O that is pressurised and launched into the air due to the forces forcing the projectile upwards from the launcher. When the completed H2O bottle projectile is sitting on the launcher. the force of the surface of the launcher pushes the projectile up whilst gravitation drags it down. As the fluid inside the projectile is pressurized. the forces become imbalanced and let go of the clinchs that are keeping back the projectile. The fluid will so be expelled through the little gap at the underside of the projectile ( the bottles nozzle ) at a fast rate in one way and hence supplying a batch of push into the other way. leting the projectile to impel upward. This force will go on to thrust upwards until the last of the fluid is expelled from the projectile ( Moore. 2014 ) .

To increase stableness in the projectile. the Centre of force per unit area and Centre of mass should be in specific places on the projectile. The Centre of mass is to set merely. a balance point in an object. It is a unvarying gravitation field that averages the external forces environing the object to equalize the forces moving upon it. such as a balance point on a see-saw ( HyperPhysics. 2000 ) . The Centre of force per unit area on a projectile is the mean location of the force per unit area. which varies around the surface of an object ( NASA. 2010 ) . The fives and facets of the projectile all contribute to the terminal place of the Centre of mass and force per unit area and so the Centre of mass should be as near to the center as possible. with besides the Centre of force per unit area towards the dorsum of the projectile. which is achieved by the usage of large fives or fives that add weight to the rear of the projectile. When building the projectiles. there are things to see: Newtons First Law: – Objects at remainder will remain at remainder. or objects in gesture will remain in gesture unless acted upon by an imbalanced force. When the projectile is sitting in the launcher. the forces are balanced because the surface of the launched pushes the projectile up while the force of gravitation forces it down.

When the H2O projectile is pressurised. the forces become imbalanced and push will supply upward way for the projectile to follow. Newtons Second Law: – The acceleration of an object is straight related to the force exerted on the object and oppositely related to the mass of that object. The acceleration of the projectile will depend on how much push and force is put behind the upward strength to help the projectile. Newtons Third Law: – For every action. there is ever an opposite and equal reaction. When the projectile launched. there will be air retarding force and gravitation pulling against the projectile. along with the upward push provided. Sing the design of the bottle projectile. fives play a major function in calming and efficaciously forcing the projectile to increase the projectiles aeromechanicss.

If the fives are excessively far frontward on the projectile it could set off the Centre of mass and therefor cause the projectile to go to a great extent unstable. Some general tips for the five design are that they should be thin or tapered. angled backwards and with rounded corners instead than crisp corners ( Williams. 2014 ) . This experiment is being conducted to research the diverse variables involved with the projectiles and how they function. and to analyze and research farther probes included in the topic of the natural philosophies field that contributed to the apprehension of the projectiles.


The purpose of this undertaking is to research the cardinal rules of projectile design and stableness needed to develop the projectiles. It is to detect the effects a scope of variables has on the H2O projectile and how those variables affect the consequences gathered.


I hypothesise that our projectile will make highs to about 20m. at an acceleration rate from 8m/s to 15m/s.


The variables involved in this probe are categorised into three sets ; independent. dependant and controlled. The independent variable involved in this experiment is clip. The dependent variables involved in this experiment are height. the angle of the projectile. the H2O degree inside the projectile and the overall acceleration of the projectile. The controlled variable involved in this experiment is clip once more.


The setup used throughout this probe included:
– x4 1. 25L fictile Pepsi™ bottles
– x2 black refuse bags
– x1 hot gum gun
– x1 Stanley knife
– x4 manilla booklets
– about 5m of twine
– 2 full axial rotations of clear tape
– scissors
– 500g of Plasticine


Rocket 1:
Measure 1: First. insight thoughts for design of H2O bottle projectile ( e. g. five design. how many fives will be needed. nose cone design. parachute design. bottle type ) Measure 2: Gather all stuffs needed to build rocket Step 3: Begin with building the fives. hint design and cut them out of chosen stuff for the fives ( for this experiment. thin composition board manilla booklets were used ) . Step 4: After finalizing fin design and building. grade where the fives will be placed on the projectile. so attach to said projectile ( for this experiment. a hot gum gun was used to attach the fives ) Step 5: After Step 4: chose and finalise design for parachute ( in this experiment. a round parachute was chosen to be constructed. cute out of a black refuse bag. with a diameter of 65cm ) . Step 6: After finalization of parachute. attach 8 strings of a length of 60cm at equal intervals around the perimeter of the parachute. procuring them with a knot so that they don’t go unattached.

Besides cute a little clasp in the Centre of the parachute about 5cm in diameter. Measure 7: Design nose cone ( for this experiment. the design was a crisp cone form created by a cut out from a manilla booklet. blunted with the Plasticine wrapped around it ( the underside of another projectile was used to organize the nose cone ) . Step 8: Tie the 8 strings used for the parachute in a knot at the underside of the lengths of the twine so glue them to the underside of the projectile in the Centre ( the base of the projectile ) . Step 9: Cut little channels in the nose cone surplus in order for a more unafraid tantrum over the parachute and projectile. Measure 10: Wrap a little sum of Plasticine around a golf ball to heighten extra weight to the projectile.

Rocket 1 alteration:
1: Nose cone had to be altered due to impact of launches ; tape was used to cover the nose cone to forestall farther harm. 2: Fives were covered in tape to do them smoother and to diminish wind clash.

Rocket 2:

As for Rocket 1. Both projectiles constructed were in direct image of each other. the 2nd 1 was a back-up projectile if you will. in instance terrible harm came to the first projectile.

Rocket 2 alterations:

1: The twine was changed on this projectile. as a pattern launch caused the parachute to rend. The twine was changed to some kind of string ; the back-up projectile was non used in the concluding testing.


s= supplanting ( m )
v= concluding speed ( m/s )
u= initial speed ( m/s )
a= acceleration ( m/s2 )
t= clip ( seconds )

1st launch:
1st image:

2nd image:

3rd image:

Overall acceleration for Launch 1:

Height for Launch 1:

Height for Launch 2:

Height for Launch 3:

Continuances of Calculations are in Appendixs.

Table 1: 300ml
Launch 1
Angle ( grades )
Time ( s )
2. 2


1. 44


2. 25
54. 00
1. 96

Table 2: 400ml
Launch 2
Angle ( grades )
Time ( s )
2. 22


2. 06


2. 09
25. 33
2. 12

Table 3: 500ml
Launch 3
Angle ( grades )
Time ( s )
2. 72


2. 56


3. 25
57. 33
2. 84

Analysis of Consequences

Observations from launch 1 were that the tallness dramatically declined when the H2O projectile was filled with 400ml of H2O. The projectile went higher when more H2O was added to it.


The purpose of this undertaking was to research the cardinal rules of projectile design and stableness needed to develop the projectiles. It is to detect the effects a scope of variables has on the H2O projectile and how those variables affect the consequences gathered. This purpose was straight achieved through doing facets of the projectile a fluctuation. for illustration the H2O degree. The projectile constructed had three different H2O degrees. which was the chosen variable to fluctuate from 300ml. 400ml and 500ml. As stated in the hypothesis. when the projectile was filled with 500ml of H2O it travelled to a higher degree than when the projectile was filled with 300ml and 400ml. Therefore. the consequences are in documentation with the hypothesis Unfortunately. when the consequences are viewed it can be seen that there is a immense bead in tallness for the 400ml launch. This was due to human mistake. as the projectile had a malfunction right before take-off ( the olfactory organ cone fell off ) .

Human mistake can be an tremendous defect in the consequences received as one minor miscue from the individual could ensue in a complete alteration in every consequence already established. Failings in the experiment were administration. how the projectile building took up most of the assessment period. and when concluding testing came about. a choice squad member did non to the full lend to the recording of the informations and so defected the full group with their ain actions. Performance information of the projectile constructed demonstrated that betterment was required in the needed added protecting of the nose cone and placement of the golf ball to guarantee the parachute was deployed successfully after launch.

Alterations made resulted in smoother take-off and landing. plus less indirect harm to the projectile. If the experiment was re-done. a new group would be requested as the group that was worked with for this probe was dreadfully con-operative. with lone three members basically making all the building while the staying member did non do any attempt at all to lend to the building of the projectile. and alternatively take to disregard the group to travel off and make their ain thing. Further probes that could be conducted with the newfound cognition of this geographic expedition could include 1s on how does endure impact the projectiles? How can the most “perfect” projectile be achieved? And what would be the most effectual stuffs to utilize when building the projectile?


In decision. the purpose of this probe was to research H2O projectile design and other cardinal rules of the projectiles. so to detect the effects the field of variables had on said H2O projectile. Throughout this probe the purpose has been achieved through fluctuation of design options for facets of the projectiles e. g. five shape/size. nose cone form and parachute design. Another fluctuation observed on the projectile was H2O degree held in the projectile to supply push for the projectile to go upwards from the launcher. All in all. the probe was successful in researching the effects that variables had on the projectiles height and weight. It was an gratifying experiment to carry on and aside from minor human mistake. the geographic expedition went without a enlistment.

HyperPhysics. 2000. Center of Mass. [ Online ]
Available at: hypertext transfer protocol: //hyperphysics. phy-astr. gsu. edu/hbase/cm. hypertext markup language [ Accessed 3 April 2014 ] .
Moore. S. . 2014. Design Consideration for Water Bottle Rockets. In: S. Moore.
erectile dysfunction. Water Bottle Rockets. Gold Coast: Helensvale. p. 1. NASA. 2010. Center of Pressure. [ Online ]
Available at: hypertext transfer protocol: //www. grc. National Aeronautics and Space Administration. gov/www/k-12/airplane/cp. hypertext markup language [ Accessed 3 April 2014 ] .
Williams. A. . 2014. Bottle Rocket Design. In: A. Williams. erectile dysfunction. Class Notes. Gold Coast: Helensvale. p. 2.


Continuance of Calculations:
Launch 2:
Image 2:

Image 3:

Image 4:

Image 5:

Overall acceleration for Launch 2:


Week 1

This hebdomad was used to get down brainstorming thoughts for the projectile theoretical account. Variations in fin size. form and place were discussed. along with nose cone and overall building thoughts for the projectile. It was decided at the terminal of the hebdomad that the five would be a rhombus form. 15cm long. and 12cm broad. with another. smaller fin inside of it to add weight. The nose cone would besides hold a rounded point.

Week 2

This hebdomad. building of the fives and bottle began. as a squad member was off for the full hebdomad. non as much assembly of the projectile occurred. but by the terminal of the hebdomad. the fives had been constructed and parachute thoughts had besides been brainstormed. The terminal of the hebdomad it was decided that the parachute would be round. A nose cone besides was constructed. it being a rounded cone form. with a blunt tip. Puting Plasticine on the nose cone would do the nose cone more aerodynamic and would add more tallness to the initial take-off.

Week 3

By this hebdomad. building of the projectile was good underway. with the fives and parachute finished and a backup projectile get downing to take topographic point. All that was needed was to brace the projectile and have a finished merchandise. It was besides decided what variable would be tested during the testing. which would be the H2O degree at 300. 400 and 500ml.

Week 4

This hebdomad. building was finished. with trouble. There were complications with the gluing of the extension that would keep the nose cone on the projectile. as it was positioned incorrectly on the projectile and had to be redone. A squad member said that the projectile would necessitate more weight to brace it and so a golf ball was covered in Plasticine. Ideas were brainstormed on how the parachute would be attached to the projectile and it was decided that the knot at the terminal of the twine would merely be glued to the dorsum of the projectile. and this was achieved successfully.

Week 5

This hebdomad. proving began. Not many projectiles. including our group. worked that good. The bulk of nose cones in groups had to be remade due to them non coming off during take-off and landing. and fives had to be re-glued onto projectiles as they were ripped away due to the force of push from take-off.

Week 6

Testing was good underway this hebdomad. but alterations still had to happen on the majority of the projectiles. even though they were going minor jobs. This hebdomad. ? of the group were off at EXCITE cantonment and unbeknown to the remainder of the group. the concluding member made a immense faulty alteration to the projectile ( the parachute was taken off it and refashion with different twine ) . Fortunately a backup projectile had been pre-made with a more practical parachute and that projectile would be officially used for the concluding testing. which would happen following hebdomad.

Week 7

This hebdomad. the concluding testing Sessionss 1 and 2 ensued. It was fantastic to see all the other groups patterned advance from Week 2 to now. how their projectiles have changed and been modified for the better. The first concluding trial. which occurred on Wednesday 12th March for our groups’ projectile had the H2O degree at 300ml. which produced a reasonably good launch. but the angles were away balanced. as the projectile was launched on an angle. which affected the full flight way. The 2nd trial. which happened on Friday 14th March. produced somewhat better consequences. as we had two take-offs during the session. the first one being perfectly perfect but non being captured by the lady keeping the high velocity camera. and had to be redone. This would ensue in a fluctuation of consequences as when the 2nd trial occurred. right before the projectile set off from the dais. the nose cone tilted at an dismaying rate. which threw off the aeromechanicss of the full projectile and negatively affected the consequences. contrary to the perfect initial take-off.

Week 8

This hebdomad. testing was finished and computations became underway. happening out the acceleration and speed took up most of the hebdomad. The assignment became at hand. work on that was indispensable. Not much practical things got done this hebdomad ; practically all lessons were done calculating out how to cipher the speed. acceleration etcetera.