Science sure is fun. While you may need to control your youngster's curiosity a little, it is important that you don't discourage it entirely. Curiosity, and science, will take your child a long way toward learning about the world. Observing, Organizing, and Comparing Science is a way of looking at things. It is a way of organizing knowledge and reorganizing it again when the evidence demands it.
Science requires careful observation and critical thinking.
It demands, and encourages, an open mind. Help your child to look closely at things. Help him to compare things. Look at plants. Look at animals.