High Density vs. Low Density Trash bags

By: Caitlin White

Purpose

• To see which density of trash bag can hold the most weight before breaking.

Research Low density Garbage bags are made from polyethylene polymers which

come from ethylene gas. Ethylene gas derives from a natural gas called ethane gas. The steps for making a low density trash bag is very complicated. The first step is to feed the ethane gas into a thermal cracker which converts it into ethylene gas. Then it travels to a reactor that converts it into polyethylene polymers which are formed into pellets like objects. Then the pellets go through a process called extrusion that turns it into plastic. This process happens when the pellets are put into a machine which is heated to 200 degrees Fahrenheit, then its blown into a tube like shape and it is set to cool.High Density trash bags are very thin compares to low density bags but the process of making them are very similar. High density bags are great for holding papers, grass clippings, cups, and etc. High density trash bags also have a great resistance of heat from -40 degrees Fahrenheit to 212 degrees Fahrenheit.

Hypothesis

• My Hypothesis is that the low density trash bag will hold the most weight ,because those are the bags that we use the most and it is thicker then the high density bags.

Materials

• High Density trash bag .3 mils (mils are a unit of measurement that equals one one-thousandth of an inch)

• Low Density trash bag .9 mils• Trash can• Weights

Independent and Dependent Variable and Control

• Independent:The amount of weight• Dependent: The breaking of the trash

bag• Control: The trash can, the type of

weights

Procedures

• Place the trash bag into trash can without placing the trash bag around the rim

• Put the weight into the trash bag• Pick up the trash bag close to the bottom

where the weight is at but do not touch the weight

• Keep adding weight and picking up the trash bag until it breaks

• Record the amount of weight it can hold

Data

Low density High density12.5 kg 17.5 kg

27 lbs and 8.92 oz

38 lbs and 9.29 oz

High density trash bag picture

Before After

Low density trash bag picture

Before After

Pictures of the Materials

Conclusion

• My hypothesis was wrong the high density bag held more weight then the low density bag. Even though the low density bag tears less, the high density bag can hold the most weight. If I were to do this experiment again I would have used different brands of high and low density bags.

Works cited

<http://www.ehow.com/how-does_5017226_plastic-trash-bags-made.html

http://www.cleaningproductsworld.com/high-density-trash-bags-waste-can-liners.html

http://www.plasticplace.net/productlist/Garbage-Bags----Black/2

http://faculty.washington.edu/finlayso/Polyeth/Group_C/pro/index.html