Topic: Separation of heterogeneous mixtures

Target group

Elementary school student (grades 7. and 8.)

Core curriculum:

Elementary school. Chemistry.

I. Substances and their properties. Pupil:

6) mixes and selects the method of separating the mixture components (eg, filtration, distillation, separation of liquid in the separator); indicates these differences between the physical properties of the mixture components that enable it to be separated.

General aim of education

The student uses different methods of separating heterogeneous mixtures.

Key competences

• communication in foreign languages;

• digital competence;

• learning to learn.

Criteria for success
The student will learn:

• how to plan ways of separating mixtures into components (eg water and sand, water and table salt, chalk and rock salt, sulfur and iron filings, water and edible oil, water and ink) and perform the appropriate activities yourself.

Methods/techniques

• expository

  • talk.

• activating

  • discussion.

• exposing

  • film.

• programmed

  • with computer;

  • with e‑textbook.

• practical

  • exercices concerned;

  • experiment.

Forms of work

• individual activity;

• activity in pairs;

• activity in groups;

• collective activity.

Teaching aids

• e‑textbook;

• notebook and crayons/felt‑tip pens;

• interactive whiteboard, tablets/computers.

Lesson plan overview

Introduction

1. The teacher hands out Methodology Guide or green, yellow and red sheets of paper to the students to be used during the work based on a traffic light technique. He presents the aims of the lesson in the student's language on a multimedia presentation and discusses the criteria of success (aims of the lesson and success criteria can be send to students via e‑mail or posted on Facebook, so that students will be able to manage their portfolio).

2. The teacher together with the students determines the topic – based on the previously presented lesson aims – and then writes it on the interactive whiteboard/blackboard. Students write the topic in the notebook.

3. Health and safety – before starting the experiments, students familiarise themselves with the safety data sheets of the substances that will be used during the lesson. The teacher points out the need to be careful when working with them.

Realization

1. The teacher asks students to explain the concept of a heterogeneous mixture and to remind people how to separate mixtures into ingredients. Students work using the snowball method. First, they work on the issues in pairs, then combine into fours, compare the collected information, verify it and set a common position. In the next stages, they merge into more numerous groups and again the information is verified and a common version is established until a general class definition and methods for the separation of mixtures are created..

2. The lecturer asks students how they would split peas and poppy, potatoes and water, as well as magnesium chips and zinc nuggets. Students discuss, present their proposals and together with the teacher verify them. They write conclusions (task 1).

3. The teacher instructs students to follow the instructions 2 and 3. Selected people discuss their ideas and compare them with the methods presented in the films. The teacher complements or straightens the statements of the pupils.

4. The teacher dismisses the class participants to the abstract and asks them to familiarize themselves with the experience instructions. Divides students into groups and distributes the right equipment, glass and reagents to perform experiments. Students follow the instructions. They record the observations in the form. The teacher asks questions in relation to the observations recorded. It initiates a discussion, the conclusions of which students write on the form.

5. Students perform interactive exercises. The teacher makes sure that the tasks have been correctly completed and give feedback.

6. The teacher asks students how they would separate multicomponent mixtures. The students give their suggestions and together with the teacher verify them. Then the lecturer proposes that the students check experimentally how many colors the black mascara is made of. The experiment will be carried out at home by chromatography. It tells you how to perform the experiment and what equipment will be needed for it: a black felt‑tip pen, a strip of tissue paper, a jar with a screw cap, a spoon of acetone (either vinegar and ethyl alcohol). The results of the experiment and conclusions will be presented by students at the next classes.

Summary

1. Teacher asks: If there was going to be a test on the material we have covered today, what questions do you think would you have to answer? If the students do not manage to name all the most important questions, the teacher may complement their suggestions.

2. The teacher displays the criteria for success and asks the students to assess their skills acquired during the classes.

Homework

1. Make at home a note from the lesson using the sketchnoting method.

The following terms and recordings will be used during this lesson

Terms

Texts and recordings

Separation of heterogeneous mixtures

• The mixtures can be separated using various techniques.

• Separation methods depend on the type of mixture and use the properties of its components.

• The methods for separating homogeneous mixtures include: solvent evaporation (eg water), distillation, crystallization, chromatography.

• The methods of separation of inhomogeneous mixtures include: sedimentation, decanting, filtration, mechanical separation, separation by means of a separator.

• Some techniques should be used when separating some mixtures. When separating the mixture of rock salt and chalk, we should successively: dissolve the mixture in water (rock salt will dissolve), filter (chalk will remain on the filter), evaporate the filtrate (rock salt will remain).