Post-it's Experiment
Materials
-4 Post-its
Steel Washers
-3 Paper Clips
-1 Recording Sheet
Scientific Explanation
When a post-it is stuck to an object there is an area where the two objects make contact, the bigger that area is the larger the strength connecting the two objects is. Rough objects have a large area where the post-it won't make contact with it, so post-its stick better on smooth surfaces.
Fixed Variable
The fixed variables needed in order to have a fair test are 1) The same sized,fresh(not used) post-its. 2) The same sized paperclips- unbent for a hook and sticky taped to the post-it in the same postition
To find out the shear strength of a Post-it note. (the shear strength is the "sliding" strength as opposed to the "peel" strength which would need a different test,but can be done too.
Aim
Change Variable
The independent variable will
be the surface to which it is stuck.
Measured Variable
The dependent variable will be the number of steel washers the post-it can hold before un-sticking.(shearing off the surface).
Results
First Surface
2nd Surface
3rd Surface
Wood
Glass
Fabric
Number Of Washers
29
16
3
Conclusion
It was found that the post-it on a wood surface held the most washers, glass held the 2nd most and fabric held the least. I think this happened because post-its are designed for smooth surfaces.
Hypothesis
It is predicted that the
Post-Its note on a smooth
surface will hold more washers than a Post-It note
on a rough or fabric surface. I
think this becouse the adhesive used on the note is
designed for smooth surfaces
like paper, note boards and table tops.
Conclusion
Method
Observations
1) While the post-it is still connected to the pad of post-it noted, tape the un bent paperclip in place(note the postion so it can be repeated.
It was found that the post-it on a wood surface held the most washers, glass held the 2nd most and fabric held the least. I think this happened because post-its are designed for smooth surfaces
2) Affix the post-its note to the first surface. (e.g white board).
I noticed that none of the post-its showed anysigns of stress when they had washerson them.
3) Place a washer at a time on to the hook.
4) Load the hook until the post-it shears off the surface.
5) It's shear strength is the number of washers before it fell.
6) Record observations on the recording sheet.
7) The test is to be repeated for the second and third surfaces.