My PBL Project-Physics

My Action Video:

Driving Question:

How does the Ruben's Tube work?

Answer:

The tube is a four meter section of pipe that has 200 holes, evenly spaced, drilled into it. The ends of the tube are then sealed and the flammable gas is pumped into the tube. the gas that leaks out of the perforated holes is lit.The building pressure within the tube will then only have one route to equalize and the standing waves will create points with oscillating (higher or lower) pressure and points with constant pressure.When introduced to any loudspeaker of sorts, waves will be seen forming in the ignited flames flowing through the 200 holes pierced into the metal pipe. Where there is oscillating pressure less gas will escape and the flames will be lower due to the sound waves. At the pressure nodes the flames will be higher

My PBL project is the Ruben's Tube.

Pictures of my experiment materials:

Materials:

Ventilation Ducting,Brackets x2, Propane Tubing Hose, T Connector, Hose Splicers x2, Latex Sheets Scrap,

WoodTools and Supplies:

Drill HammerTape Measure Knife or Scissors Silicone Sealant Epoxy Putty Duct Tape Masking Tape Teflon Tape

Procedures:

First - determine what will be the top side of the tube. there's a seam on where the ends of the tube connect, this will be the bottom.

Second - Run a piece of masking tap along the top of the ducting. Using a tape measure mark off every half inch running down the center of the tape.

Third - Using a nail, or other object carefully tap a point in each marking with a hammer. The goal is to create a small depression at each location to facilitate drilling.

Fourth - Remove the tape and carefully drill through the ducting at each depression.

Fifth- Use duct tape to cover the potentially sharp edges of the tube - this will prevent the ducting from ripping through the diaphragm. You'll probably want to use more than one layer, Depending upon the type of material you're using, it may not be necessary.

Sixth- Cut a latex sheet to serve as your diaphragm. You'll definitely want to cut it large enough to completely cover the end of the tube with enough extra to tape down and pull taut. the use of polyethylene sheeting will work, however latex will provide additional flexibility. It's also worth noting that latex will slowly oxidize, and may need replacing over time.

Seventh - Start taping the sheeting down to create the diaphragm. The concept here is to basically emulate the head of a drum. It needs to be tight enough to allow it to easily vibrate, but not so tight that it will tear. Once satisfied tape down, or trim the excess, and tape around the circumference of the tube in order to create an airtight seal.

Eighth - On the other end, repeating the processes will allow for later experiments using a "stereo" Rubens' Tube. However, simply sealing it off with duct tape to create a good seal is a perfectly acceptable method to create a functioning device. In either case, be careful what you set the opposite end on to make sure you preserve airtight seal.

Ninth- Finally, it's worth while to run a bead silicone sealant down the seam of the tube. I pressed it into the joint using my finger, and then cleaned up the excess. Now we have our tube completely sealed where we want it to be.

Tenth - Determine the location(s) where fuel will enter the ducting. Additionally, depending upon whether or not you choose to have fuel delivered at more than one location, a bit of advance planning should go into where these locations are. It's also worth noting, again in retrospect, that one point for fuel delivery would probably work equally as well, so long as this location is centered.

Eleventh - As in the prior step, tap your marked location with a nail, and drill a hole large enough for your hose splicer to fit. Using hose splicers will make hooking everything up much easier.

Twelfth - Using a utility knife, nail, or other sharp object, lightly score the ducting around the hole, or holes. This should allow for the epoxy to create a more secure bond.

Thirteenth - Install the hose splicer(s) in the hole(s). Mix up some epoxy putty, and apply liberally. You'll want to create both an airtight and secure bond.

Fourteenth- Teflon tape on the areas where you'll be attaching the tubing is a good idea to make sure you won't have propane leaking. This includes the propane nozzle, the tee connector (if you're using multiple delivery points for fuel), and end of the hose splicer(s) that will connect to the tubing.

Fifteenth- Hooking up the fuel is a pretty straight forward process. Simply cut and attach the hose. To do this, you'll want a cup of very hot water close by to soak the ends of the tubing in, this will warm and soften it up so you can easily get it over the connections.If you're using one entry point for fuel, you'll only have one connection to make right now, if you're using a tee connector for two entry points, connect both ends to connector, and to the Rubens' Tube.

Sixteenth - Attach the brackets to the base using screws.

Seventeenth- This step may or may not be required depending upon how your tube fits in the brackets. During construction the brackets might be slightly larger than the ducting. To aid this, use some scrap hosing and zip ties to put around the ducting, thus adding to the circumference.

Eighteenth - Finally, mount the Rubens' Tube inside the brackets. Tighten up the brackets and you should be left with a fairly stable setup.At last!

Nineteenth- Please read the safety notes before hooking up the propane and continuing.

And always remember safety first!!

The Science behind Ruben's Tube:

Ruben’s tube is based on Bernoulli’s principle.

“Gas flow is proportional to the square root of the pressure difference between the pressure outside of the tube and the pressure inside of the tube.”

The tube is a four meter section of pipe that has 200 holes, evenly spaced, drilled into it.

The ends of the tube are then sealed and the flammable gas is pumped into the tube.

the gas that leaks out of the perforated holes is lit.

The building pressure within the tube will then only have one route to equalize and the standing waves will create points with oscillating (higher or lower) pressure and points with constant pressure.

When introduced to any loudspeaker of sorts, waves will be seen forming in the ignited flames flowing through the 200 holes pierced into the metal pipe.

Where there is oscillating pressure less gas will escape and the flames will be lower due to the sound waves.

At the pressure nodes the flames will be higher