premise: there is a negatively-charged piece of cloth sent2: a cloth is a kind of object sent3: there is a negatively-charged plastic strip sent4: a plastic strip is a kind of object sent5: if two objects have the same electrical charge then those two objects will repel each other when they are close to each other sent6: charge is a property of an object and includes ordered values of negatively-charged / neutral / positively-charged.
hypothesis: a leaf absorbs sunlight to make food