How are Earth features, such as sinkholes, formed? Objective Students will gather evidence from various sources to understand that Earth events, such as erosion, can occur at different rates—some quickly and others slowly—leading to features like sinkholes. Background To successfully implement this second-grade lesson on erosion and sinkholes, the teacher needs a solid understanding of the geological processes involved in erosion, particularly how different types (water, wind, ice) shape landscapes over varying time scales. Familiarity with the formation of sinkholes, including factors like un Duration: 60 Minutes.