Finalised project- Appendix D

APPENDIX D

Science Investigative Project

Project Proposal Form

Name:

Shi Yuexin ( 21 )

Sec 2/13

Topic of investigation :

Effect of different types of bags filled with water when a sharp pencil is poked right through it.

A	Observations made
	When a zip-lock bag is filled with water and then a sharp pencil is poked right through it without being removed, water doesn’t leak out of the bag. This is due to a special characteristic of the zip-lock bag (see below). What will happen if the same experiment is conducted on other different types of bags?
B	Research Question
	Does the type of bag affect whether a sharp pencil can be poked through it without water spilling out?
C	Hypothesis statement
	The type of bag does affect whether a sharp pencil can be poked through it without water spilling out.
D	A short summary of research done on the area of investigation
	The zip-lock plastic bag is made up of polymers, which are long chains of molecules that give the bag its ‘stretchy’ properties. When the sharp pencil is poked through a zip-lock bag filled with water, the pencil slips in between the molecules strands without tearing the other parts of the bag. Furthermore, the long chains of molecules even seal back around the pencil to prevent the water from leaking out. On the other hand, paper is mainly made up of cellulose which has weak hydrogen bonds. This may cause a whole paper bag to tear when a sharp pencil is poked through it when it is filled with water. Also, wet paper has weak fibres that will cause it to be torn more easily than dry paper. Thus, water would most likely spill out of a paper bag when it is poked through with a sharp pencil.
E	Bibliography (Please refer to RS Students’ Handbook in RS Folder on Inet regarding APA Style Format)
	-Steve Spangler Science The Leak-Proof Bag Retrieved from http://www.stevespanglerscience.com/ -Yahoo Answers! In terms of molecules, how does water soak a piece of paper? Retrieved May 26, 2011 from http://answers.yahoo.com/ -Yahoo Answers! It is much easier to tear wet paper than dry paper. Why? Retrieved May 26, 2011 from http://answers.yahoo.com/