Sand and silt are both examples of granular materials, which are collections of separate particles and distinct particles, such as raw flour in a container or jellybeans in a jar.The most common forms of sand and silt are composed of tiny fragments of quartz.
Rip tides, also known as rip currents, are strong narrow currents that can pull swimmers out to sea. Some rip tides are so strong that they can drag swimmers away from shore before they realise what is happening. Swimmers should keep an eye out for rip tides while swimming in the sea at the beach. Rip tides can be identified by discoloured water, choppy waves and a foamy surface. They can be filled with debris. Swimmers are told to remember the âthree Rsâ if they become caught in a rip tide.
These are white with red vertical stripes and indicate unobstructed water on all sides. They mark mid-channels or fairways and may be passed on either side. Mooring Buoy. These are white with a blue horizontal band. They usually are placed in marinas and other areas where boats are allowed to anchor. These are the only buoys you may tie up to legally. Inland Waters Obstruction Marker. These are white with black vertical stripes and indicate an obstruction to navigation. You should not pass between these buoys and the nearest shore.