Sky-Chaser Web Site (Chris Collura - KG4PJN)

This area shows my work with tesla coils as well as other "cool" and intriguing science experiments. First of all, my "weird" science section mainly is toward my work with Tesla coils. A tesla coil is an ultra-high voltage science project using a high voltage primary power supply, a capacitor matched to a primary coil of heavy guage wire, a spark gap, and a secondary of many turns of thin wire. A tesla coil, in electrical engineering terms, is both a high frequency RC (resistor and capacitor) oscillator and an air core transformer. The combination of the high voltage power supply (such as a neon sign transformer), the capacitor, and primary coil form the RC circuit. The spark gap, produces spikes in the voltage, and triggers many harmonics (multiples of the 60 Hz input frequency) that are enhanced by the RC circuit. The primary coil, wrapping around the secondary coil, produces an intense high frequency magnetic field that induces a high frequency current in the secondary coil, even though air separating the two.

Such frequencies are in the RF (radio freqnency) range and can be from 100 to 500 kHz. Output voltages can be in the tens (or even hundreds) of thousands of volts, or more! Tesla coils are not difficult to construct, as a matter of fact, nearly all their components can be found at the local hardware store and are inexpensive. Anyone with a good understanding of electronics can construct such a device. This interesting page shows my work in this exiting area of electronics.

DANGER - Tesla coils involve extremely high voltages and their construction / use requires a thorough understanding and respect for electricity. The voltages and equipment described in their section are not toys. Carelessness and lack of knowledge with such high voltage applications CAN KILL YOU!! I assume no responsibility for anyone who gets hurt from attempting or using any technique or device displayed in this section. Two rules of thumb, if you don't know what you are doing, don't do it! Plus, when making adjustments, any electrical adjustments, unplug it!! The tesla coil project is aimed mainly at the scientific and tesla coiler community. I intend to use my tesla coil for lightning demonstrations and entertainment.

Other pictures and resources to interesting and / or unique scientific experiments are also portrayed on this page, also called "Weird Science"!

Note - This page may take a while to load on some SLOWER connections!

CHOOSE A VIDEO CLIP BELOW - LINKS TO YOUTUBE

Tesla Coil Project Video Clip

Air Gun Video Demonstration

TESLA COIL PROJECT - CHOOSE A LINK BELOW

First Tesla Coil - Part One
Second Tesla Coil Attempt - Part Two
Finished Coil - Part Three
Functional Tesla Coil - Part Four
Dual Tesla Coil - Part Five
Big Tesla Coil - Part Six
Table-Top Tesla Coil - Part Seven
High-Power Tesla Coil - Part Eight

WEIRD SCIENCE - LIQUID OXYGEN (LOX)

Liquid oxygen (or LOX) is a cryogenic liquid for of oxygen and is extremely cold at about -298 degrees below zero farenheit (-193 celsius). It is a pale blue liquid and accelerates combustion violently because it offers roughly 4,000 times the available oxygen in the air we breath. It has many uses, from medical supplies (for oxygen therapy) to rocket fuel oxidizers. LOX is dangerous because of two reasons, first of all, it is extremely cold, and can freeze anything on contact. Second, it accelerates combustion rather quickly, how quickly? You will see a demonstation of this in this section! Here I will fill a normal plastic party cup about 1/3 full of LOX from a medical supply Dewar of LOX. I will then place a piece of paper towel in the cup, place it in an open area of grass, light the paper with a cigarette lighter, and get away!

This is a picture of the plastic cup filled about 1/3 with liquid oxygen. As you can see, the LOX is pale blue in color and bubbling since the room temperature rapidly causes the liquid to boil off into oxygen gas, which is colorless.

Here is the same cup, with a piece of paper towel in it, being lit with a cigarette lighter (carefully!) and placed in an open area in the grass. Now it is time to get away quickly and watch from roughly 30 feet away.

The flame burns the top of the paper towel normally, and continues downward until reaching the LOX soaked portion of it at the bottom of the cup. The LOX, providing nearly 4,000 times the oxygen to the burning paper towel that air would, bursts into a violent and brilliant yellow flame. The paper towel along with the entire plastic cup is also consumed in about 3 seconds with a distinct "whoosing" sound.

Here is what is left afterwards. The cup and paper towel is completely gone! The intense heat of the reaction that just took place also creates a large burn mark in the grass. This is why LOX is so dangerous around anything combustible. Don't smoke around LOX either.

WEIRD SCIENCE - PNEUMATIC CANNON

This section has been dedicated to my first attempt at building an "air cannon" (pneumatic gun). This is basically a launching device built out of PVC piping so that pressurized air can force (or shoot) a projectile at high velocities. The cannon is constructed of three basic parts: an air reservoir (tank), a valve (trigger), and acceleration tube (gun barrel). The main air tank is a 36" section of 2 1/2" PVC tubing with a bushing at each end with a "T" connector and another bushing near one end. The "T" bushing connects to 3/4" PVC tubing which leads to a ball valve. From the ball valve, the PVC tube curves around and mates with the end of a 62" long section of 1/2" PVC, which passes through the air chamber (tank) via the two sealing bushings at each end. A tire valve in the 3/4" PVC tube between the air reservoir and ball valve allows the cannon to be "charged" with pressure simply by closing the ball valve, filling the tank with up to 100 PSI of air then loading the barrel with a projectile, such as a wire-cap, marble, wood dowel, etc. Aim the cannon at a target away from people and property, and quickly release the ball valve. The decompression fires the "bullet" down the barrel with a loud bang and into the air at the target.

This is a drawing of the schematic for the pneumatic cannon. It is made entirely from Schedule 40 (high pressure) PVC pipe solvent-welded with heavy duty PVC joining compound. Designed to be charged with an air pressure load of 100 PSI, a quick-release of a ball valve can send a marble sized projectile out the barrel at aircraft velocities.

Image is scaled ... Click on the image to the left for the full size picture.

This is a picture of the pneumatic canon (air gun) itself. The barrel is pointed away and the firing end with valve and assembly can be seen in the foreground. Note the small tire valve for pressurizing the unit and modified handle of the ball valve for easy leverage. The unit was covered with aluminum tape for added safety and painted yellow with black trim for cosmetic appeal.

This picture shows the "projectile" to be fired, a small 1/2" glass marble. The blue colored marble in this picture is being dropped into the end of the gun barrel where it rolls down to the other end. The unit is not designed to fire in a downward angle because of this, but is very easy to load.

The first test of this air gun was up against a small but thick phone book (yellow pages). In this video-frame picture, the gun was rigged with a baffle of bricks and boards allowing various "targets" to be set up at point-blank range. The gun is charged to about 45-50 PSI using an ordinary bicycle pump, then triggered via the ball-valve. The marble is accelerated to high speed and impacts the phone book. In this picture, the impact point is just above the space between the yellow on black words "ALL ACCIDENTS". Note the vapor stream from the gun muzzle to the right caused by sudden "decompression" and cooling of the air allowing moisture to condense.

This picture shows the impact damage to the phone book after the test. The marble easily penetrated most of the pages and blew out sucessively larger holes the deeper into the book it went. The view here is looking from the "exit wound" side of the target (projectile impacted the opposite side relative to this picture).

The next test subject was a 3/8" thick disk of plywood. The air gun was re-charged to about 50 PSI and loaded with the same marble (interesting how strong a glass sphere can be). The board is no match for the projectile, puncling a clean "bullet hole" right through it. The yellow on the plywood is old paint. Note the flying piece of debris just above the center of the picture and slightly right in the background.

Here is a view of the other side of the 3/8" plywood disk after the test. The exit side of the hole is even clean. The marble this time struck the cinder-block baffle behind the board and disintegrated.

The more realistic test of this air gun involved a potato to show the effects on something organic. Here a red potato is positioned about 10 inches in front of the muzzle of the air gun, a marble loaded, and the unit pressurized.

The gun is fired by releasing the ball valve and the marble impacts the potato. The resulting impact completely destroys the potato with a loud bang.

This picture shows what could be salvaged of the red potato after the test. The potato was completely "blown up" by the shot. In this picture, the large chunk of the potato even shows a channel (starting from the palm of my hand and to the right across the lower portion of the chunk) where the projectile sliced through before blowing the potato apart. After this test, the air gun was dismantled.

HTML File "tesla.htm" - Developed By Chris Collura

To Return To The HOME Page Of This Site Click The "INDEX.HTM" Link Here!

	This is a picture of the plastic cup filled about 1/3 with liquid oxygen. As you can see, the LOX is pale blue in color and bubbling since the room temperature rapidly causes the liquid to boil off into oxygen gas, which is colorless.
	Here is the same cup, with a piece of paper towel in it, being lit with a cigarette lighter (carefully!) and placed in an open area in the grass. Now it is time to get away quickly and watch from roughly 30 feet away.
	The flame burns the top of the paper towel normally, and continues downward until reaching the LOX soaked portion of it at the bottom of the cup. The LOX, providing nearly 4,000 times the oxygen to the burning paper towel that air would, bursts into a violent and brilliant yellow flame. The paper towel along with the entire plastic cup is also consumed in about 3 seconds with a distinct "whoosing" sound.
	Here is what is left afterwards. The cup and paper towel is completely gone! The intense heat of the reaction that just took place also creates a large burn mark in the grass. This is why LOX is so dangerous around anything combustible. Don't smoke around LOX either.

	This is a drawing of the schematic for the pneumatic cannon. It is made entirely from Schedule 40 (high pressure) PVC pipe solvent-welded with heavy duty PVC joining compound. Designed to be charged with an air pressure load of 100 PSI, a quick-release of a ball valve can send a marble sized projectile out the barrel at aircraft velocities. Image is scaled ... Click on the image to the left for the full size picture.
	This is a picture of the pneumatic canon (air gun) itself. The barrel is pointed away and the firing end with valve and assembly can be seen in the foreground. Note the small tire valve for pressurizing the unit and modified handle of the ball valve for easy leverage. The unit was covered with aluminum tape for added safety and painted yellow with black trim for cosmetic appeal.
	This picture shows the "projectile" to be fired, a small 1/2" glass marble. The blue colored marble in this picture is being dropped into the end of the gun barrel where it rolls down to the other end. The unit is not designed to fire in a downward angle because of this, but is very easy to load.
	The first test of this air gun was up against a small but thick phone book (yellow pages). In this video-frame picture, the gun was rigged with a baffle of bricks and boards allowing various "targets" to be set up at point-blank range. The gun is charged to about 45-50 PSI using an ordinary bicycle pump, then triggered via the ball-valve. The marble is accelerated to high speed and impacts the phone book. In this picture, the impact point is just above the space between the yellow on black words "ALL ACCIDENTS". Note the vapor stream from the gun muzzle to the right caused by sudden "decompression" and cooling of the air allowing moisture to condense.
	This picture shows the impact damage to the phone book after the test. The marble easily penetrated most of the pages and blew out sucessively larger holes the deeper into the book it went. The view here is looking from the "exit wound" side of the target (projectile impacted the opposite side relative to this picture).
	The next test subject was a 3/8" thick disk of plywood. The air gun was re-charged to about 50 PSI and loaded with the same marble (interesting how strong a glass sphere can be). The board is no match for the projectile, puncling a clean "bullet hole" right through it. The yellow on the plywood is old paint. Note the flying piece of debris just above the center of the picture and slightly right in the background.
	Here is a view of the other side of the 3/8" plywood disk after the test. The exit side of the hole is even clean. The marble this time struck the cinder-block baffle behind the board and disintegrated.
	The more realistic test of this air gun involved a potato to show the effects on something organic. Here a red potato is positioned about 10 inches in front of the muzzle of the air gun, a marble loaded, and the unit pressurized.
	The gun is fired by releasing the ball valve and the marble impacts the potato. The resulting impact completely destroys the potato with a loud bang.
	This picture shows what could be salvaged of the red potato after the test. The potato was completely "blown up" by the shot. In this picture, the large chunk of the potato even shows a channel (starting from the palm of my hand and to the right across the lower portion of the chunk) where the projectile sliced through before blowing the potato apart. After this test, the air gun was dismantled.