How to detect explosives?

Answer 1

Sometimes you can smell them; but that is why they train dogs to do it (dogs have better sense of smell).

In todays world there are so many types of explosives not all can really be detected through smell.

Answer 2

Photoluminescence spectroscopy: New technique for detecting explosives
Although spectroscopy is an old technique, it has been recently applied to the detection of explosives. This technique helps in identifying the explosive element from the molecules released by exposing a high power laser beam on it or in its vicinity. The excited molecules give off photons (light) of the characteristic wavelength of the material when the light source is removed.

My name is rashmi and i am very interested in science. A week before I had made a simple spectroscope for the science exhibition and I won second prize in it.

A spectroscope is a device that lets us find out what things are made of. It works by taking light and splitting it up into its component colors. Different elements make different colors when they glow. We can make objects and gasses glow by heating them up in a flame, or by passing electricity through them. The spectroscope spreads out the colors of the light, and we can identify the elements by the bright lines we see in the spectroscope.

steps for making a home made spectroscope

What we will need:

A CD or DVD that can be sacrificed to this project. We won't damage it, but getting it back will involve destroying our spectroscope. Old software CDROMs work great, and some can be had for free from internet service providers like AOL.

A cardboard box. An 8 inch cube works fine, but any size that can hold a CD or DVD disk will do.

Two single edged razor blades. These can be found in paint or hardware stores.

A small cardboard tube, the kind used as a core to wrap paper on.

Some cellophane tape.

Some aluminum tape (found in hardware stores), or some aluminum foil and glue.

Our spectroscope has three main parts. There is a slit made from two razor blades, a diffraction grating made from a CD disk, and a viewing port, made from a paper tube.

To make sure that all three parts are lined up properly, we will use the CD disk as a measuring device, and mark the spots where the slit and the viewing port will go.

Set the CD disk on top of the box, about a half inch from the left edge, and close to the box's bottom, as shown in the photo. Use a pen to trace the circle inside the CD disk onto the box. This mark shows us where the paper tube will go.

Now place the paper tube on the box, centered over the circle we just drew. Draw another circle on the box by tracing the outline of the paper tube.

Move the paper tube over a little bit. A half-inch is probably fine -- in the photo I placed it much farther to the right than necessary, but the aluminum tape covered up the mistake nicely. Trace another circle around the paper tube. These circles will tell us where to cut the box.

Now cut an oval out of the box with a sharp knife. The oval will allow the paper tube to enter the box at an angle.

The next step is to make the slit. Turn the box one quarter turn so the oval we just cut is to the right. Using the CD disk again, draw another small circle close to the left side of the box.

The slit will be on the far left of the box. Cut a small rectangle out of the box at the height marked by the small circle we made with the CD disk. The rectangle should be about a half inch wide, and two inches high.

Carefully unwrap the two razor blades, and set them over the rectangular hole. Make their sharp edges almost touch. Tape the razor blades to the box, being careful to leave a gap between the sharp edges that is nice and even, and not wider at the top or bottom.

Next, set the box right-side-up, with the slit towards you. Now tape the CD disk onto the back wall of the box. The rainbow side should face you, with the printed side touching the cardboard. The photo shows the disk a little too far to the left. The left edge of the disk should be the same distance from the left of the box as the slit is.

Now seal up any places on the box where light might leak in. Use the aluminum tape for this. You can also use aluminum foil for this purpose if you don't have any aluminum tape.

The last step is to use the aluminum tape to attach the paper tube. The aluminum tape will make a light-tight seal around the tube. To make sure the angle is correct, hold the slit up to a light, and look through the paper tube, adjusting it until you can see the full spectrum from red to purple.



That's it! We are ready to use the spectroscope.

Answer 3

OKay I admit they are machines to detect the explosives., But the place which you are landing is important, to detect the explosives.

Answer 4

Machines or trained dogs.