do detectives use flashlights to check crime scenes when they could just as easily turn on a light first?
962054
Besides officer safety, using a flashlight to search and examine a crime scene serves several legitimate investigative purposes.  I have been a cop for 11 years - 3 1/2 of those years have been as a detective - and can give some real life examples.\n\n(1) OBLIQUE LIGHTING - Sometimes light applied from different angles makes something more visible.  Here is an example you can try at home.  Go outside at night and step in the dirt.  You will leave behind a shoe print.  Take a bright flashlight and shine it down on that footprint from straight above.  You will see that the detail of the footprint is washed out by the bright light.  Now, take the same light down to almost ground level and shine it along the ground over the footprint.  You will see how the ridges and details in the footprint become much more visible.  This technique works with fingerprints too!\n\n(2) FOCUSED FIELD OF VIEW - Searching an otherwise dark area is often helpful in finding small items as it allows you to focus on the small area illuminated by the flashlight rather than to focus on a much large, more widely illuminated area.  Here's another way to illustrate this principle.  When you look at a whole page in a "Where's Waldo" book, Waldo is hard to find.  Now take a toilet paper roller and look at the same page through the tube like a telescope.  Move the tube around the page.  You will see that, once Waldo falls into your field of view, he will stand out much more plainly due to the much smaller "focused" field of view.\n\nUsing a flashlight rather than touching the switches, walls, etc., also ensures that any fingerprints, DNA evidence, etc., that may be present in the area you might touch will not be disturbed.
529120
All fo answers above me are all wrong, Police depts uses surefire flashlights, Even our military use it too!
882739
The best way to find out might be simply re-open the door to see if the light IS out!
411460
nope... it would have a delay.  I would guesstimate that it would take about 30-45 seconds for the light to come on.   I am just guessing here.
802337
In the states (Nevada), a police vehicle is recognized as an emergency vehicle regardless if the lights & siren are on or not. The reason is that a police vehicle approaching a crime scene may need to approach without broadcasting his presence, yet may still speed. For fire & ambulance, the lights and sirens must be activated for the vehicle to have an emergency status.
1051664
i live in maine and washington state, and ive been everywhere inbetween, in my opinion most police dont have the capability to deter or detect anything smarter and more dangerous than a jelly donut,  this is just a general biased observation.
39200
Yes, but mostly for kid patrol. if I see the light in the hallway go dim or shadows it lets me know that one of the kids are up and wandering about, or they have had a nightmare and need tucked back into bed with pleasant thoughts.
512651
Okay i am not a csi officer nor to i plan to do to that. I am a pd officer and when we do small investgatiosn we collect all evidance at the scene we never look for prints back at the station that be dumb . We do take evidance back to the lab and station but not like that not unless we found like a person or something that was needed for trail in the can itself.
737866
i think that because we have more cameras we can detect crimes more easily... as most people do not know that they are being watched they commit these crimes, remeber if a crime is seen then it has to be reported...\n\nif there is no camera in a place that a crime has been commited where no one is present then its could be hard to determine if a crime has occured... therefor it is not reported...so there seems to be less crime...\n\ndid that make sense?\n\nhope so!\n\nx
316086
Yes, but not as often as TV makes it appear. Usually they are on call expet some are full tie profilers - who also have police work training.
271273
Not especially. In order to see in the dark, you'd need some new types of photoreceptors in your eyes. Short of bionic eyes, nanotechnology, or genetic engineering, good luck with that.
21945
first. hollywood, dramatic effect\nsecond, cops use flashlights so that if there is a burgalor and he is trying to catch the cops or hurt them (or something of that sort) then they use flashlights because the robber would see a bright light in a dark place, so it would be nearly impossible to hit the cop. (In real life, cops use a flashlight that blinks so the robber would see a light and then itd go away and he wouldnt know where to shoot. [think of a firefly])\nCSI .. some good stuff. ..
796240
no,  remember that many police departments don't have crime scene techs,  the actual officers do all of thier own work,  or they are just dectives that do the investigations.\n\nAll my years in uniform, from robberiers to fraud, to theft, to assult,  we always did our own crime scene investigation and collected our own evidence.  We then checked them into evidence storage, and the evidence supervisor took them and sent them into a crime lab.\n\nAnd most small departmetns ( I would bet and it is a guess) I would bet about 90 percent don't have crime labs or crime scene techs.\n\nSo you are left with first a small number of departments scattered all accross the US.  And each one will have various degrees.  Some may require thier own state POST training and certification from POST as thier requirements.\nOthers will look for those trained at state crime labs.\n\nI have not checked in years, but Southeast Missouri University, used to have a progam that worked with the MO State Crime lab, where students could work on actual cases and evidence.\n\nI don't know if they still offer it but they used to
775133
It's not too unusual for a details of an investigation to change slightly. Remember, most of the Officers are coming into a situation blind, they don't know what happened, they don't know who is involved and the biggest thing is they don't know who is honest or a lying puke. The initial investigation is what the players tell the Police. As evidence proves (or disproves) the sworn testamonies of witness's, Offenders, etc. the story can be entirely different that what was sworn to in the beginning. I always say, "Ignorance is blind"- If you REALLY want to see what happens in a full police investigation, take a good Criminal investigations course at your local community college. DON"T go what you see on TV! It's mostly Bull except shows like "Cold Case files, but even then, remember, it takes years to wrap up an investigation, Not 1/2 hour.
948741
How light guns work\n\nThe "light gun" is so named because it uses light as its method of detecting where on screen you are targeting. The name leads one to believe that the gun itself emits a beam of light, but in fact most light guns actually receive light through a photoreceptor diode in the gun barrel. [Re].\n\nThere are two versions of this technique that are commonly used, but the concept is the same: when the trigger of the gun is pulled, the screen is blanked out to black, and the diode begins reception. All or part of the screen is painted white in a way that allows the computer to judge where the gun is pointing, based on when the diode detects light. The user of the light gun notices little or nothing, because the period in which the screen is blank is usually only a fraction of a second.\n\nSequential targets\n\nThe first detection method, used by the Zapper, involves drawing each target sequentially in white light after the screen blacks out. The computer knows that if the diode detects light as it is drawing a square (or after the screen refreshes), that is the target the gun is pointed at. Essentially, the diode tells the computer whether or not you hit something, and for n objects, the sequence of the drawing of the targets tell the computer which target you hit after 1 + ceil(log2(n)) refreshes (one refresh to determine if any target at all was hit and ceil(log2(n)) to do a binary search for the object that was hit).\n\nAn interesting side effect of this is that on poorly designed games, often a player can point the gun at a light bulb, pull the trigger and hit the first target every time. Better games account for this by detecting if all targets appear to match - that would mean cheating.\n\nCathode ray timing\n\nThe second method, used by the Super Nintendo Entertainment System's Super Scope and computer light pens is more elaborate but more accurate.\n\nThe trick to this method lies in the nature of the cathode ray tube inside the video monitor. (CRTs were the only affordable TV monitors in the late 1980s and early 1990s, when this method was popularized.) The screen is drawn by a scanning electron beam that travels across the screen starting at the top until it hits the end, and then moves down to update the next line. This is done repeatedly until the entire screen is drawn, and appears instantaneous to the human eye as it is done very quickly.\n\nWhen the player pulls the trigger, the computer (often assisted by the display circuitry) times how long it takes the electron beam to excite the phosphor at the location the gun is pointed at. It then calculates the targeted position based on the monitor's horizontal refresh rate (the fixed amount of time it takes the beam to get from the left to right side of the screen). Either the computer provides a time base for the horizontal refresh rate through the controller's connector (as in the Super Scope), or the gun reads the composite video signal through a T-connector on the A/V cable (as in the GunCon 2). Once the computer knows where the gun is pointed, it can tell through collision detection if it coincides with the target or not.\n\nMany guns of this type (including the Super Scope) ignore red light, as red phosphors have a much slower rate of decay than green or blue phosphors. So some (but not all) games brighten the entire screen for a frame in order to get a more reliable fix on the position.\n\nDisplay timing is useless with plasma, LCD, and DLP, which refresh all pixels at the same time.\n\nCombining the methods\n\nSome light guns designed for sequential targeting are not timed precisely enough to get an (X, Y) reading against the video signal, but they can use a combination of the two methods. First the screen is brightened and the response time is measured as in cathode ray timing, but the computer measures only which scanline was hit and not which horizontal pixel was hit. This does not need nearly as fast a timer that pure ca
808047
By touching the lamp you are changing the capacitance of the lamp and a circuit inside the lamp detects the change and turns on the light. \n\nIn order to offset sensitivity to temperature and other objects near the lamp it is designed to be triggered by a sudden change in capacitance - so when you slowly touch it, or tap it with an object with insufficient cpacitance then the circuit does not detect enough of a change to trigger.
41488
I would guess that we use a car,because we all know what they are. We also know that cars have headlamps located on the front. We further know that the light is projected so as to illuminate the area in front of the car. What we DON'T know, is how to get one of them to move at C...No, not even your best chevvy.