9 An Experiment on Plastic Bag
A Brief Introduction to the expriment
As we all know, there are two kinds of plastic bags. One kind is innoxious, and can be used to pack food. The other kind is noxious，and can only be used for general packaging, while running the danger of poisioning when used to pack food. So, how to distinguish the two kinds of plastic bags? We will use the following experiment to illustrate.
Burn and Smell Method
|Innoxious plastic bags burn quickly and continue to burn even when removed from fire. The flame is yellow and the melting plastic falls drop by drop,just like candle, with the smell of mineral wax.||The noxious red plastic bag hardly burns, and it burns with green flame and choking smell.|
|Innoxious plastic bags have the following features: It feels very smooth when we touch the surface of the white plastic bags. It sounds clear when we shake it hard.||However, the blue and red plastic bags in our hands are noxious ones. Their color is not clear;it feels tacky and unsmooth; it sounds not clear when shaked.|