Plastic wrap becomes electrically charged when pulled from its box. As a result, it is attracted to objects such as food containers. Does the wrap stick better to plastic containers or to metal containers?
Solution 7E Step 1: First, we should understand how plastic wrap is getting charged when it is pulled from the box. This is due to the static electricity, which will generate inside the plastic wrap as a part of friction between the box when it is pulled. If it is pulled from the box, charge transfer will take place between the box and the plastic wrap. As a result, it will gain some additional electron. So, the plastic wrap will be negatively charged. Since, the box has some loss of electrons, it will be positively charged. Step 2: When the charged plastic wrap is placed near a plastic container, it will polarize the charges in it as represented in figure 1. If the plastic wrap is brought closer, it will repel the electrons in the plastic container which will move to the opposite side of the container. This electron deficiency in the adjacent sides of the plastic container will create a net positive charge. Since, the plastic container has been an insulator, the charges will remain as polarized and the polarized plastic container will attract the negatively charged plastic wrap more. Hence, the sticking effect will be more.