Here's another drawing/diagramming activity to help us understand some differences between the geocentric and heliocentric models. Feel free to complete this activity by hand or use computer/tablet software or apps. Create a diagram of Earth, Venus, and the Sun in the geocentric model. Show the phases of Venus that we would observe throughout one of its orbits. Create a diagram of Earth, Venus, and the Sun in the heliocentric model. Show the phases of Venus that we would observe throughout one of its orbits