Anderer Ressourcentyp

Siemens Stiftung

Detection reaction for unsaturated fats

Photo series:
Seven photos show the different steps of an experiment for detecting unsaturated fats using iodine and starch.

The first photo shows the preparation for the experiment, and photos 2 through 6 show the experiment being conducted. The seventh photo shows the result of the experiment.
The photos can be displayed in succession. For each photo, an explanation can be displayed and hidden.

Information and ideas:
The photos are also available as individual media files on the media portal of the Siemens Stiftung.

Bild

Siemens Stiftung

Detection reaction for unsaturated fats (6)

Photo:
After the test tube containing the olive oil is shaken for about three minutes, a blue coloration does not appear.

Bild

Siemens Stiftung

Detection reaction for unsaturated fats (2)

Photo:
Addition of iodine/potassium iodide solution: Exactly two drops are added to each test tube.

The big advantage of using a commercially available, ready-to-use solution from a pharmacy or a laboratory supply company for the iodine/potassium iodide solution is the consistent composition. Self-prepared I2/KI solutions vary in their concentration. The iodine contained in the added solution is taken up by unsaturated fats. This will play an important role later when starch powder that is at least partially water-soluble is added.

Experiment

Siemens Stiftung

C3 How does human digestion break down fats? (teacher instructions)

Experimentation instructions for Experimento | 10+:
Background information on the content and practical information on conducting the experiment "How does human digestion break down fats? - Saponification of edible oil". This experiment comprises two subexperiments.


These simple experiments for the emulsification and saponification of fats are well suited as an introduction to the topic of digestion and metabolism in the human body. Starting from the experiment that merely demonstrates that fats can be split into fatty acids, the topic must then be related to human digestion. These teacher instructions provide information and suggestions for this. The materials and apparatus supplied are sufficient to allow eight groups of students to conduct the experiments simultaneously.

The experiment comprises two subexperiments:

· We emulsify oil
· Saponification of edible oil

Notes:
· Observe the safety information in the instructions as well as the applicable safety guidelines for your school.
· All materials mentioned in the instructions will have to be purchased directly from commercial sources.

Anderer Ressourcentyp

Siemens Stiftung

The micelle

Interactive schematic diagram:
The components of a micelle can be labeled interactively.

The graphic shows the structure of a lipid micelle, how the micelle is formed in the human body during the fat digestion process, and its components: bile salts, monoglyceride, cholesterol, phospholipids, apolar lipids, and long-chain fatty acids.

The graphic can be labeled individually or as a whole.

Bild

Siemens Stiftung

Detection reaction for unsaturated fats (4)

Photo:
Addition of soluble starch to olive oil (on the left). The starch serves as an indicator of "free iodine? through the formation of a blue iodine/starch complex.

Note: The test tube must be shaken before the detection result can be evaluated.

Anderer Ressourcentyp

Siemens Stiftung

C3 How does human digestion break down fats? (worksheet 2 answer sheet)

Answer sheet:
For the worksheet of the same name for subject teaching in English.


You can find more detailed information on the associated worksheet for subject teaching in English "C3 How does human digestion break down fats? (worksheet 2),? which is available on the media portal of the Siemens Stiftung.


Dieses Material ist Teil einer Sammlung

Arbeitsblatt

Siemens Stiftung

C1 We burn sugar (worksheet 2)

Worksheet for subject teaching in English:
For the student experimentation instructions of the same name. Methodology tool: dialogue developed by Josef Leisen and Heinz Klippert.


Note: This worksheet has been developed especially for subject teaching in English and for language-sensitive subject teaching. It uses the dialogue methodology tool developed by Josef Leisen and Heinz Klippert. The dialogue is well suited for presenting technical topics in a lively manner and integrating them into descriptive actions. The dialogue provides initial approaches for participating in a technical debate.
Students whose native language is not English and who do not have strong English skills receive support and training in understanding the technical vocabulary. They work with the specialized vocabulary and in this way acquire the ability to communicate about specific subjects.


Dieses Material ist Teil einer Sammlung

Bild

Siemens Stiftung

Basic building blocks of fats

Chemical structural formulas:
Glycerol, simple fatty acids, triglyceride, and cholesterol.

Glycerol and fatty acids are the basic building blocks of fats (lipids). Fats are the product of the esterification of the trivalent alcohol glycerol with fatty acids of different lengths (between 12 and 20 carbon atoms). Two important representatives of the lipids are triglyceride (90% of fats) and cholesterol.

Medientypen

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Lernalter

16-18

Schlüsselwörter

Fats Metabolism Molecule Nutrition

Sprachen

Englisch

Bild

Siemens Stiftung

Detection reaction for unsaturated fats (7)

Photo:
Reaction products without blue coloration (olive oil) on the left and with blue coloration (butter and iodine/starch complex) on the right.

Left: A lack of blue coloration means that an iodine/starch complex is not present. Therefore, the available iodine was taken up by unsaturated fats. Consequently, olive oil contains unsaturated fats.
Right: The presence of blue coloration (after about 3 minutes and after shaking) means that an iodine/starch complex has formed. Therefore, the available iodine was not taken up by unsaturated fats. Consequently, butter does not contain unsaturated fats.