Separation of Mixtures
3 Minutes
Separation of mixtures for students explains sedimentation, decantation, filtration, and magnetic separation. An English science lesson.
- Sedimentation and decantation shown with muddy water in a glass
- Purifying water by trapping tiny dust particles with filter paper
- Using magnetic separation to remove iron particles from waste
What this lesson teaches
Separating mixtures is the process of taking apart combined substances that cannot be used in their mixed form. While some mixtures like juice, ice cream, and cement can be used directly, other mixtures like muddy water or rice mixed with stones must be separated first.
Why mixtures need separation
- Living beings need water to survive, but humans purify drinking water to remove impurities that are mixed inside it.
- Many mixtures can be used directly as they are, including food items like sambar, juice, ice cream, and cement used at home.
- Other mixtures cannot be used directly, such as dirty water or cooking rice that is mixed with stones.
- Specific separation methods must be used to remove unwanted substances from these mixtures.
Sedimentation and decantation
Sedimentation begins by placing muddy water in a glass and leaving it undisturbed for some time. As the liquid sits quietly, suspended particles slowly settle down at the bottom of the glass. These settled particles are called sediments, and the process of settling is called sedimentation. Decantation follows by carefully pouring the relatively clear water into another glass while leaving the sediment behind.
Purifying water with filtration
Water collected after decantation may still appear slightly cloudy because tiny dust particles remain in it. Further purification is done through filtration, which depends mainly on filter paper. The holes in the filter paper are much smaller than the tiny dust particles mixed in the water. Pouring the water through traps the dust in the filter paper, allowing only clean water to pass down.
Magnetic separation
- Magnetic separation is the process of separating magnetic particles that are mixed together with non-magnetic particles.
- Bringing a magnet near soil causes magnetic particles in the dirt to stick to the magnet while the soil stays below.
- Industries use this technique to separate iron particles from mixed waste materials.
- Waste is moved over a magnetic belt so magnetic particles stick to the belt while the remaining waste travels forward.