What do they look like? Tree swallows are small birds (about 14 cm long) with long wings and small legs and feet. They are irridescent greenish-blue on their head, shoulders and back, and white their chin, breast and belly. Tree swallows have a short black beak and dark brownish feet.
Ernest Rutherford concluded that an atom contains a very small, dense center, called a nucleus, with a positive charge as a result of his gold foil experiment.
according to jj thomsons model of an atom,an atom consists of a positively charged sphere with electrons in it.however,it was later found that positively charged particles resâ¦ide at the center of the atom called nucleus,and the electrons revolve around the nucleus.