Pure substances, mixtures, and how to separate them…

Separation of Substances

The separation of components in a mixture is very important in many science fields. When scientists need to study one particular component of a mixture, various separation methods are used. These methods take advantage of the differences in the physical properties of the substances to be separated.

After reviewing the differences between chemical elements, compounds, and mixtures, we discussed some common reasons and methods for separating out the components of a mixture. Students were given a mixture of sand, rice, and iron filings and worked in teams to design and implement a multi-step purification process for this mixture, taking advantage of the different physical properties of each component to recover as much as possible. Various tools were provided, including many household items such as colanders, sieves, coffee filters, magnets, and utensils. Students used magnets to separate the iron fillings from the mixture and sieves were the most popular item used to separate rice and sand.

Additional Information:
Music Video – Meet the Elements (3:15) – file://localhost/They Might Be Giants https//:www.youtube.com:watch%3Fv=Uy0m7jnyv6U


Separación de Sustancias

Poder separar los componentes que constituyen una “mezcla” es un proceso muy importante para distintas disciplinas de la ciencia. Cuando los científicos necesitan estudiar un componente particular de una mezcla, pueden ocupar diversos métodos de “separación”. Estos métodos, generalmente utilizan las propiedades físico-químicas de las sustancias. En esta clase, repasamos las diferencias entre los elementos químicos, compuestos y mezclas; también discutimos sobre  las razones y métodos más comunes para separar los componentes de una mezcla.

A los estudiantes se les entregó una “mezcla” que contenía arena, arroz y hierro. Se agruparon en equipos para diseñar e implementar un proceso de varios pasos de purificación de esta mezcla. Tomando en cuenta las diferentes propiedades de cada uno de los componentes, la meta era recuperar la mayor cantidad de cada uno de los componentes. Además, se les entregó varias herramientas para poder trabajar, incluyendo variados artículos para el hogar como coladores, tamices, filtros de café, imanes y utensilios de cocina. Los imanes fueron utilizados por todos los grupos para separar el hierro de la mezcla, y los coladores fueron el utensilio más popular para separar la arena y el arroz.

Información adicional en el siguiente link:

Video musical: “Conoce los Elementos” (3:15) por They Might Be Giants



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Dr. Catherine Sukow

Dr. Sukow's interest in science education began when she was a teenager, with an extended visit to San Francisco's Exploratorium. In college, she had summer jobs in a similar, smaller, museum. She focused her Master's research at NCSU on the structure of metal silicides on silicon, and her Ph. D. work at Brandeis on the structure of crossbridged actin bundles. While volunteering in her childrens' schools, she was reminded how much fun it is to teach science, and is happy to be teaching now with Science from Scientists. In her spare time, she also enjoys yoga, choral and solo singing, and attempting a variety of international cuisines.

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