Final answer:
Galileo used sketches in his notes to visually represent and record his observations and discoveries. These sketches served as visual evidence and helped communicate his scientific findings.
Step-by-step explanation:
Galileo used sketches in his notes to aid in his studies because they allowed him to visually represent and record his observations and discoveries. By creating sketches, Galileo was able to accurately document the details of what he observed through his telescope, such as the moons of Jupiter. These sketches served as a form of visual evidence that supported his scientific findings and helped him communicate his discoveries to others.