So take any discoveries you make in this project VERY seriously, as you will be the first person in the history of the world to have seen this. Then you must do the other necessary part of being a scientist - publish what you saw so that others might know about it also. Now it needs to be greatly expanded to show its comprehensiveness. This mental image should help in designing your experiment. But defective tires are a safety hazard because if put under unusual stress, they will fail.
Failure results in a fracture through which the innertube herniates and explodes.
This would be like testing the strength of a bike tire on a rough road of sharp gravel. Just as with the tire, the stresses on the cell can be purely physical - sudden decompressions, or bumping into sharp objects. Just to really give the cells a lot of stress, freeze them and thaw them through 5 or 8 cycles. Before you go any further, you must be skilled in the art of counting live bacteria using a method called plate counts . There is a sneaky way to do this using far fewer plates.