Julie the Scientist has a Question. Why is the river green during the summer?
First, she looks at what other scientists have said about the river. Her friend Jimmy says that the river is green every summer for as long as he’s been watching it.
Julie thinks there may be something growing in the river that makes it green.
She takes some river water back to her lab.
When Julie looks under the microscope, she sees little green balls!
Julie is curious about these little green balls. She wonders what makes them grow in the summer but not the winter.
Julie makes a list of what is different between the summer and the winter:
Julie does some experiments to see what makes the little green balls grow better. She makes sure to keep some of them on the side, so she knows what they do without the experiment.
When she adds more water, they don’t grow better.
When there are more animals in the water, the green balls don’t grow at all.
When the water is hotter, they grow much better.
When there is more light, the green balls grow faster.
Julie decides that the sunlight and heat make the little green balls grow better. She writes down her results in a Journal, so other scientists can find what she did.