When using a model to explain the phases of the moon, there are several limitations we need to consider.
First, the size of the moon and the Earth in the model might not accurately represent their real sizes. The moon is much smaller than the Earth, but in a simple model, they might look similar in size, which can be confusing.
Second, the distance between the Earth, moon, and sun is really vast in reality. If models use small distances for convenience, it can mislead us about how the moon moves around the Earth and how it reflects sunlight. This can make it harder to understand how the phases change.
Lastly, the model may not show the exact angle of the sun's light hitting the moon. The light from the sun creates different phases like new moon, crescent, and full moon based on how much of the moon we can see from Earth. If the model doesn't demonstrate this correctly, it won’t accurately explain why we see different phases.
So, while models can help us understand the phases of the moon, we need to remember that they have limitations in size, distance, and light angles.