Topic: Physical phenomenon and chemical transformation

Target group

Elementary school student (grades 7. and 8.)

Core curriculum

III. Chemical reactions. Pupil:

Elementary school. Chemistry.

1) describes and compares the physical phenomenon and the chemical reaction; gives examples of physical phenomena and chemical reactions taking place in the human environment; designs and conducts experiments illustrating the physical phenomenon and chemical reaction; based on observations, classifies transformations to chemical reactions and physical phenomena.

General aim of education

The student distinguishes the physical phenomenon from chemical transformation

Key competences

• communication in the mother tongue;

• communication in foreign languages;

• mathematical competence and basic competences in science and technology;

• digital competence;

• learning to learn.

Criteria for success
The student will learn:

• describe the differences between physical phenomenon and chemical change;

• give examples of physical phenomena and chemical changes taking place in the human environment;

• design and perform a simple experiment illustrating physical phenomena and chemical reactions;

• apply safety rules when performing chemical experiments.

Methods/techniques

• activating

  • discussion.

• expository

  • talk.

• exposing

  • film.

• programmed

  • with computer;

  • with e‑textbook.

• practical

  • exercices concerned.

Forms of work

• individual activity;

• activity in pairs;

• activity in groups;

• collective activity.

Teaching aids

• computers with internet access, or tablets;

• e‑textbook;

• projector;

• interactive whiteboard, tablets/computers;

• methodician or green, yellow and red cards;

• equipment, laboratory glass and reagents for the experiment - see description of Experiments 1, 2, 3 in the abstract and in the methodical commentary.

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 refers to various examples of processes from the human environment, as a result of which new chemical substances are created or not. He asks the question, which connects all the changes in the first case, and what is the common denominator in the second type of processes. It helps students to define the concepts of physical phenomenon and chemical change.

2. The teacher displays on the multimedia board the gallery „Transformation of matter” from the abstract, encourages students to discuss. Then, he instructs students to prepare an observation journal in abstract (or gives pre‑prepared work sheets or recommends writing in notebooks) - displays on the multimedia board the film „Getting plastic sulfur” from the abstract. Students formulate a research question and hypotheses, record observations during the experiment and set conclusions in the indicated place (diary, work sheet, notebook).

3. The teacher asks the students the question: „What changes make one substance transform into another?”. In initiating the discussion, the teacher displays on the multimedia board the „Transformation in our surroundings” gallery. Then he instructs the students: „Do hair cutting and dyeing are the same kind of changes? Specify these processes. Is sculpting in wood and firing patterns in it are transformations of the same kind? Name them „.

4. The teacher displays the film „Burning sulfur” from the abstract on the multimedia board. The students formulate the research question and hypotheses as previously, they write in the indicated place, as well as observations and conclusions.

5. The teacher formulates the question: „What is the difference between physical phenomenon and chemical change?” Then he conducts a teacher's show „Mixing sulfur with iron and heating the resulting mixture”. The students formulate the research question and hypotheses again and, like observations and conclusions, note them in the indicated place.

6. By referring to the show, the teacher writes in words the equation of the chemical reaction that took place during the experiment. Signs substrates, products and defines them, students write them in notebooks. Then introduces the concepts of chemical reaction equation and reagents. It displays on the multimedia table a table „Examples of reaction equations with the determination of individual substances involved in chemical transformation”.

7. The teacher asks students to do an interactive exercise in an abstract (individual work).

Summary

1. The teacher asks the students to finish the following sentences:

   • Today I learned ...

   • I understood that …

   • It surprised me …

   • I found out ...

   The teacher can use the interactive whiteboard in the abstract or instruct students to work with it

Homework

1. Listen to the abstract recording at home. Pay attention to pronunciation, accent and intonation. Learn to pronounce the words learned during the lesson.

2. 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

Physical phenomenon and chemical transformation

In our environment we can observe many tranformations in which the physical properties of matter change, but not itself. An example of this is freezing of water. The ice that is produced as a result of this process is not a new material but still water. As a result of the temperature decrease, only physical state (physical property) of the substance changes. Such process, as a result of which matter only changes its physical properties, we call physical transformation or physical phenomenon.

In our environment, many transformations can be observed, during which substances undergo constant changes and transform into other substances.

Transformations presented in above photographs take place under the influence of various factors: high temperature action, microorganisms, interaction of various substances. They have one thing in common – they result in new substances with different properties. Such processes are said to be chemical transformations or chemical reactions.

Physical phenomena and chemical transformations accompany us every day. It is not always easy to assess their type. In many cases, just process observation is not enough to determine whether a new substance was created as a result of it, or only the physical properties (e.g. state of aggregation) of the substance undergoing this transformation have changed. The factors used also do not determine the type of transformation. As a result of heating, the substance may either change physically or take part in a chemical reaction.

As a result of mixing two different substances, their mixture may be formed (physical phenomenon) or a chemical reaction may occur. This depends on properties of substances themselves and on conditions in which they are placed. In predicting the type of transformations under influence of various factors, knowledge about properties of substances is very useful.

Chemists have found a universal way of describing chemical transformations, during which one substance is transformed into another. With the help of arrow they indicate the direction of the transformation – from substances that took part in the chemical reaction to substances that were created:

$\text{substances that participated in the reaction → substances that were formed as a result of reaction}$

Substances that undergo chemical transformation are called substrates, and substances resulting from it are called products. The record, in which using arrows and molecular formulas transition from substrates to products is shown, is called chemical reaction equation. The general scheme is as follows:

$\text{substrates → products}$

In the chemical reaction equation, substrates are always on the left side of the arrow, and the products – are on the right. The arrow is directed from the substrates to the products.

In experiment 2 from sulfur and oxygen we obtained sulfur dioxide. Sulfur has reacted with the oxygen presented in the air. This reaction can be described by the following equation:

$\text{sulfur + oxygen → sulfur dioxide}$

Experiment 3, based on heating of sulfur with iron, led to the formation of iron(II) sulfide. This chemical transformation can be presented by the following equation:

$\text{sulfur + iron → iron(II) sulfide}$

Another chemical reaction, in which magnesium oxide is formed as a result of magnesium, can be described by the equation:

$\text{magnesium + oxygen → magnesium oxide}$

• Physical phenomena are based on changing the physical properties of a substance. During these processes new elements and new chemical compounds are not created.

• Chemical transformation is a process during which one substance is transformed into another.

• Substances that undergo transformations in chemical reaction are substrates, and those that result from them are products;

• The chemical reaction equation is a symbolic record of chemical reaction course. Substrates are written on the left side of the reaction equation, on the right – products. The arrow indicates the direction of the reaction from substrates to products.

products, chemical reaction equation, substrates