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.
Heavy breaking waves can trigger a sudden rip current, but rip currents are most hazardous around low tide, when water is already pulling away from the beach. In the past, rip currents were sometimes called rip tides, which was a mistake, Carey said. Tides are really slow changes in water level and by themselves do not induce a rip current, she said. A rip current is not at all a tide.. Scientists have been studying rip currents for more than 100 years.