Erosion and weathering are major forces that shape the Earth's surface. Erosion is when the Earth's surface is worn away by forces like moving water, wind, oceans, and glaciers. Weathering is when rocks are broken down into smaller pieces through various processes like freezing and thawing of water, plant roots, and chemical reactions. Understanding these forces helps explain landforms like canyons, shorelines, and how soil erosion impacts food production.