Topic: Is everything natural really natural and artificial - really artificial?

Target group

High school / technical school student

Core curriculum

New core curriculum:

High school and technical high school. Chemistry – basic level:

XXI. Chemistry around us. Pupil:

8) explains the reasons for food spoilage and proposes ways to prevent this process; presents the significance and consequences of using food additives, including preservatives.

High school and technical high school. Chemistry – extended level:

XXI. Chemistry around us. Pupil:

8) explains the reasons for food spoilage and proposes ways to prevent this process; presents the significance and consequences of using food additives, including preservatives.

Old core curriculum:

High school and technical high school. Chemistry – basic level:

XXI. Chemistry around us. Pupil:

7) explains the causes of food spoiling and proposes ways to prevent this process; presents the meaning and consequences of using food additives, including preservatives.

General aim of education

The student discusses the role of food additives and gives examples

Key competences

• communication in foreign languages;

• digital competence;

• learning to learn.

Criteria for success
The student will learn:

• to discuss the purpose of using various food additives;

• to indicate - due to the designation - some dyes, antioxidants, thickeners and preservatives that have a detrimental effect on human health ;

• to distinguish the designations of certain dyes, antioxidants, thickeners and preservatives and indicate those that may have a detrimental effect on human health ;

• to show examples of products in which food additives are included ;

• to discuss the consequences of using food additives .

Methods/techniques

• expository

  • talk.

• activating

  • discussion.

• exposing

  • exposition.

• programmed

  • with computer;

  • with e‑textbook.

• practical

  • exercices concerned.

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.

Realization

1. The teacher begins a talk class on food additives: nowadays, most food products are produced with compounds that affect their quality, e.g. taste, and durability. It is estimated that consciously or not each of us eats about 2 kg of various types of dyes, preservatives, emollients, thickeners, consistency‑forming substances, „enhancers” of flavors and others. Nearly 300 such substances have been approved in Poland. Finally, together with students, they define the concept of food additives.

2. The teacher discusses the division of food additives into natural and synthetic ones, including dyes, sweeteners, aromas, acidity regulators, thickeners and emulsifiers.

3. The teacher discusses the designation of food additives, displaying on the multimedia presentation the most frequently used substances with the symbol E [...]. They explain their harmfulness to human health.

4. At the end of the lesson, the teacher asks students to do an interactive exercise - individual work.

5. Groups have to develop content using a variety of sources (abstract, textbook or web), in the context of the role of a given food additive, examples of additives, types of dishes and food products to which they are added. All students in the group are discussing, explaining each other unintelligible issues, learning..

6. Students create new teams on the agreed sign, so that each group includes experts from all other teams.

7. Experts report on what they have learned in their original groups, ie the expert of the first group gives the others the knowledge they have gained before, after which the group II expert, group III expert, group expert, IV, group V expert. transmit information to other students until the scope is exhausted. Each group thus gets acquainted with all the material planned for implementation on a given lesson (time: about 10 minutes).

8. Experts return to their original groups, confront acquired knowledge, supplement, check to see if everyone has learned everything (time about 7 minutes). The teacher complements and optionally explains unintelligible issues.

9. The teacher discusses the designation of food additives, displaying on the multimedia presentation the most frequently used substances with the symbol E [...]. They explain their harmfulness to human health.

10. At the end of the lesson, the teacher asks students to do an interactive exercise - 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

2. The students consolidate the acquired information, discussing it with their nearest neighbors („tell your neighbor” method.

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

Is everything natural really natural and artificial - really artificial?

Consumers share a lot of excitement with the division of food additives into natural and artificial. In the colloquial evaluation, the means obtained by chemical synthesis are harmful to health, while „natural” substances, i.e. of vegetable and animal origin, obtained by fermentation or other biological processes, are safe. From the toxicological point of view, the division of food additives into healthy and harmful ones does not coincide with the division into natural and artificial additives. The important thing is whether the agent used is safe for the health of the consumer, and not which methods were used to obtain it.

Preservatives are only a small group among substances added to foods. Food additives are also used to: improve taste, smell, colour and consistency.
Addition of dyes to food raises a lot of controversy. You may find that there is an opinion that food colouring misleads consumers. On the other hand, some consumers believe that it should only be allowed to colour foodstuffs using natural and natural‑like dyes, and that synthetic dyes should be strictly forbidden. Known facts from the past could have contributed to such opinions. In 1936 it was proved that one of the commonly used synthetic dyes at that time – butter yellow – has strong carcinogenic properties. However, based on current research, colouring substances that are used in Poland do not raise toxicologists' concerns.

Sweeteners are used as table sweeteners, among others in order to give a sweet taste to foods without sugar. Demand for these substances is related to economic and health reasons (increasing number of diabetics and obese people). The intensity of the sweet taste varies depending on the type of sweetener, its concentration, pH and temperature. Model in determining the intensity of sweet taste is sucrose, the sweetness of which is assumed to be one.

• Food preservation substances have been used for thousands of years.

• Preservatives are substances that prolong food durability.

• Common preservatives are, for example, table salt, ascorbic acid, benzoic acid, sorbic acid, acetic acid.

• Not only preservatives are used as food additives, but also substances that improve the colour, consistency and taste of products are often used for this purpose.