In late winter everyone seems to look for signs of spring but are there signs of fall that we can find in late summer? Let's find out.
Make a list of things that people do as summer comes to an end. Can you come up with 5 or 10 different things? Now start watching for people doing them. Check them off when you see them happen. How many of these are because of changes in nature that are part of fall?
All right then, what are some natural signs of the coming of fall? Try to make a list of these too and then check them off as you notice them happening. Get an adult to help you make your list.
What does all this have to do with science? Plenty. There is a branch of biology called phenology which studies how living things respond to changes in climate. It pays attention to details like when birds migrate and when plants flower. It requires skills in observation and record keeping. Figuring out the connection between the climate and what plants and animals are doing is based on making inferences and, perhaps, creating and doing experiments.
There is a good explanation of the cause of the seasons at ESP's What Causes Winter page.