In school we're making an experiment where you're going to put plastic sheet over for example a pear put not the top. When i did the experiment it seems like plastic sheet won't let the microwaves in, can someone explain to me why?
There is experimental science and theoretical science. It is premature to ask the question why. Is the experiment replicable? What about different types of plastic sheet? Are they all the same or do different types respond differently? For that matter there is paper, or foil. Are they different? The reason I comment on that is that we often cover a bowl with glad wrap and heat it. The contents do get warm. so I could not agree with It seems like plastic sheet won't let microwaves in
If you are coming to that conclusion, there is something very wrong with your experimental methodology. Without more detail, it's fairly pointless to speculate what the problem may be.
