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 J.J. Thomson's model of an atom, it consists of a positively charged sphere with neutrons embedded in it. However, it was later found that the positively c â¦ harged particles reside at the center of the atomcalled the nucleus, and the electrons revolve around the nucleus.