Subject: What method of testing can i use to test factors affecting fire alarms?

I am doing a science fair project for high school and im intertested in 
Smoke detectors and how they work.  I was reading interesting information 
about them and was wondering "why do smoke detectors occasionally not go 
off"   I then though i could do an experiment to test certain problems a 
smoke detector might run into when trying to dectect a fire.  My question 
is how would i test this properly. I think what I would do would be to set 
up 3 different brands of smoke detectors at different cost and test each 
with different power batteries and see how that affects the amout of time 
it takes a detector to respond, also test with objects that might get  in 
the way of the lazer that sets off the alarm, such as cob webs and dust.I 
would like to know if that would be a reliable test or if there is another 
way i could do my experiment being more accurate?  please help me with any 
imput of my idea, or if you have a suggestion i would love to hear.
thank you
alicia    ale247f@aol.com

Re: What method of testing can i use to test factors affecting fire alarms?