Air Trajectory B/C
- bernard
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Re: Air Trajectory B/C
I don't understand your question. What is something you want to graph? What do you mean by "specific data?"HPerez10 wrote:can we make the graph on any data from our device? or does it have to include specific data?
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- bernard
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Re: Air Trajectory B/C
Our device was only shooting at most 5 meters the day before an invitational, but with some adjustments it could shoot 8 meters. Are you using a PVC barrel and ping-pong ball? How are you converting gravitational potential energy to air pressure (i.e. are you using a stomp rocket setup, 2-Liter bottle, bicycle pump, etc.)? I can help you better once I know these things.HPerez10 wrote:My event is in three days and I'm worried because I have tried multiple angles for the pipe and the ball still doesnt go far enough to reach 8 meters. My falling mass is about 7.5lbs and i dont know if that has anything to do with it? Thanks
-hannah
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Re: Air Trajectory B/C
I used a tin can filled with concrete as the mass (only 8lbs), pvc pipe, tube, and a pvc base to connect the tube to the plastic air bellow pump, which is where the mass falls on. Im also using a ping-pong ball.bernard wrote:Our device was only shooting at most 5 meters the day before an invitational, but with some adjustments it could shoot 8 meters. Are you using a PVC barrel and ping-pong ball? How are you converting gravitational potential energy to air pressure (i.e. are you using a stomp rocket setup, 2-Liter bottle, bicycle pump, etc.)? I can help you better once I know these things.HPerez10 wrote:My event is in three days and I'm worried because I have tried multiple angles for the pipe and the ball still doesnt go far enough to reach 8 meters. My falling mass is about 7.5lbs and i dont know if that has anything to do with it? Thanks
-hannah
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Re: Air Trajectory B/C
The event includes a graph to go along with it and i haven't made the graph yet. Im not sure if they're looking for specific data, such as the mass and the distance or the angles, to be in the data/graph.bernard wrote:I don't understand your question. What is something you want to graph? What do you mean by "specific data?"HPerez10 wrote:can we make the graph on any data from our device? or does it have to include specific data?
- bernard
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Re: Air Trajectory B/C
The graphs are to look for relationships - what happens to Y when you vary X. So you might vary the launch angle (that would be your x-axis variable, your independent variable) and measure the launch distance (that would be your y-axis variable, the dependent variable). With data, you can graph it and predict a trendline so you have a relationship you can use to estimate the values of points you didn't test.HPerez10 wrote:The event includes a graph to go along with it and i haven't made the graph yet. Im not sure if they're looking for specific data, such as the mass and the distance or the angles, to be in the data/graph.bernard wrote:I don't understand your question. What is something you want to graph? What do you mean by "specific data?"HPerez10 wrote:can we make the graph on any data from our device? or does it have to include specific data?
I'll go through an example. For our device, we adjust the launch distance (how far we want the ball to go) by changing the angle of our barrel. We started by testing a number of different angles: 0 degrees, 15 degrees, 30 degrees, 45 degrees, 60 degrees, 75 degrees. We did each angle three times so we have many trials, just in case if one of our trials had a lot of error and the device wasn't shooting normally. After averaging the values of the trials we did (taking the distances we measured for each trial at a specific angle and averaging them), we would then graph it in Microsoft Excel, and add a trendline to the graph. In a notes section on the same page, we would include some details about what variables were kept constant and what their values were (e.g. the mass was dropped from 0.90 meters for all trials, the ball used was a ping-pong ball, the mass used was 4.5 kg, etc.)
Hope this helps. If anything is unclear of if you feel like I haven't answered your question, please let me know.
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Re: Air Trajectory B/C
Put the ping-pong ball into your barrel, put your hand over the ball, and press down on your bellow slowly. If it isn't entirely airtight, you will feel air come out. Add some thin strips of masking or painters tape to the inside of your PVC barrel where you feel the leaks. Keep loading your ball, testing for leaks, and adding tape until you don't feel any more air leaking out, but you don't want to put too much tape (or the ping-pong ball might not launch). I recommend masking or painters tape because it is easy to remove and doesn't leave a sticky residue.HPerez10 wrote:I used a tin can filled with concrete as the mass (only 8lbs), pvc pipe, tube, and a pvc base to connect the tube to the plastic air bellow pump, which is where the mass falls on. Im also using a ping-pong ball.bernard wrote:Our device was only shooting at most 5 meters the day before an invitational, but with some adjustments it could shoot 8 meters. Are you using a PVC barrel and ping-pong ball? How are you converting gravitational potential energy to air pressure (i.e. are you using a stomp rocket setup, 2-Liter bottle, bicycle pump, etc.)? I can help you better once I know these things.HPerez10 wrote:My event is in three days and I'm worried because I have tried multiple angles for the pipe and the ball still doesnt go far enough to reach 8 meters. My falling mass is about 7.5lbs and i dont know if that has anything to do with it? Thanks
-hannah
"One of the ways that I believe people express their appreciation to the rest of humanity is to make something wonderful and put it out there." – Steve Jobs
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Re: Air Trajectory B/C
Honestly, you don't even have to tape over the inside of the barrel. That could mess with too many things. Just tape the outside of it where you here the air leaking. If it is a pretty decent sized whole, you could invest in some super glue to just put a dab or two in the holes. Make sure it is absolutely dry before you test anything. But taping the inside of the barrel just seems like it could have a worse negative effect than just taping the outside.bernard wrote: Put the ping-pong ball into your barrel, put your hand over the ball, and press down on your bellow slowly. If it isn't entirely airtight, you will feel air come out. Add some thin strips of masking or painters tape to the inside of your PVC barrel where you feel the leaks. Keep loading your ball, testing for leaks, and adding tape until you don't feel any more air leaking out, but you don't want to put too much tape (or the ping-pong ball might not launch). I recommend masking or painters tape because it is easy to remove and doesn't leave a sticky residue.
- bernard
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Re: Air Trajectory B/C
I don't understand why you would tape the outside of the barrel. Could you explain it? For a barrel that is slightly larger than the projectile, taping the inside makes the inner diameter slightly smaller so the projectile fits better. Of course you would tape carefully to avoid wrinkles in the tape.MC McGilicutty wrote:Honestly, you don't even have to tape over the inside of the barrel. That could mess with too many things. Just tape the outside of it where you here the air leaking. If it is a pretty decent sized whole, you could invest in some super glue to just put a dab or two in the holes. Make sure it is absolutely dry before you test anything. But taping the inside of the barrel just seems like it could have a worse negative effect than just taping the outside.bernard wrote: Put the ping-pong ball into your barrel, put your hand over the ball, and press down on your bellow slowly. If it isn't entirely airtight, you will feel air come out. Add some thin strips of masking or painters tape to the inside of your PVC barrel where you feel the leaks. Keep loading your ball, testing for leaks, and adding tape until you don't feel any more air leaking out, but you don't want to put too much tape (or the ping-pong ball might not launch). I recommend masking or painters tape because it is easy to remove and doesn't leave a sticky residue.
"One of the ways that I believe people express their appreciation to the rest of humanity is to make something wonderful and put it out there." – Steve Jobs
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Re: Air Trajectory B/C
My bad. I thought you were talking about having a barrel that had air leaking out of it through places other than the end of it. A tape ring to make it tight on the inside of the barrel makes sense then. Sorry about thatbernard wrote:I don't understand why you would tape the outside of the barrel. Could you explain it? For a barrel that is slightly larger than the projectile, taping the inside makes the inner diameter slightly smaller so the projectile fits better. Of course you would tape carefully to avoid wrinkles in the tape.MC McGilicutty wrote:Honestly, you don't even have to tape over the inside of the barrel. That could mess with too many things. Just tape the outside of it where you here the air leaking. If it is a pretty decent sized whole, you could invest in some super glue to just put a dab or two in the holes. Make sure it is absolutely dry before you test anything. But taping the inside of the barrel just seems like it could have a worse negative effect than just taping the outside.bernard wrote: Put the ping-pong ball into your barrel, put your hand over the ball, and press down on your bellow slowly. If it isn't entirely airtight, you will feel air come out. Add some thin strips of masking or painters tape to the inside of your PVC barrel where you feel the leaks. Keep loading your ball, testing for leaks, and adding tape until you don't feel any more air leaking out, but you don't want to put too much tape (or the ping-pong ball might not launch). I recommend masking or painters tape because it is easy to remove and doesn't leave a sticky residue.
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