Anderer Ressourcentyp

Siemens Stiftung

Reaction to produce sucrose

Interactive chemical equations:
The chemical equation for the production of sucrose can be developed interactively as a word equation and reaction equation.

The two equations can be developed in two ways:
· Entire equation at once
· Individually by educts and products.

Anderer Ressourcentyp

Siemens Stiftung

Saponification and digestion of fat

Interactive chemical equations:
The chemical equations for the alkaline saponification of fat and the breakdown of fat in human digestion can be developed interactively.

Word and reaction equations are shown for the alkaline saponification of fat; only the word equation is shown for the breakdown of fat in human digestion.
The equations can be developed in two ways:
· Entire equation at once
· Individually by educts and products.

Anderer Ressourcentyp

Siemens Stiftung

Monosaccharides

Interactive table:
For the two monosaccharides aldose (glucose) and ketose (fructose), the molecular formula, structural formula, and functional group can be worked out interactively in a table.

The interactive table can be filled out in two ways:
· All cells at once
· Each cell individually

Simulation

Siemens Stiftung

Phase transition due to pressure

Simulation:
The state of a substance depends not only on the temperature but also on the pressure. An example of this is skating on ice.

Ice skaters concentrate their body weight on a very small surface (2 thin blades). The resulting pressure (= force per surface area) liquefies the ice of the top layer. At microscopic level, this means that the water molecules are separated from their atomic binding partners inside the ice. The resulting thin film of water enables the skater to glide over the ice. The simulation shows this effect.
The whole process is augmented by a temperature effect: The sliding friction of the blades on the ice results in a very small amount of heating, which allows the ice to melt even more readily.

Information and ideas:
Ice researchers still do not always agree absolutely in which cases pressure is the dominant effect when skating on ice and in which cases friction. Scientific studies are still being carried out on this subject.
Assignment: Students should explain the melting process due to pressure using the p-T diagram.

Simulation

Siemens Stiftung

; Physics and chemistry of water: Energy storage and release using water as an example

Simulation:
Principle of energy storage and release with water as example, animated presentation.

Strictly speaking, energy is stored not only in molecular movements and vibrations but also in the transition between physical states. During evaporation and condensation, water absorbs and releases a relatively large amount of energy owing to the strong hydrogen bridge bonds.

Information and ideas:
As background for the topic "water as a means of energy storage" and "water in power generation", which is also important for thermal power engines, such as the steam engine. Even without going into thermodynamics, it is clear where steam engines get their energy from: The superheated steam contains a great deal of energy. Given the same volume, this corresponds to a high pressure that can move a piston.

Bild

Siemens Stiftung

Section of a starch molecule

Chemical structural formula:
Section of a starch molecule showing the alpha-1,4 glycosidic bonds in amylose.

Starch is a prominent example of plant polysaccharides. It has a soluble component (25%) and an insoluble component (75%). The soluble component, the amylose, forms long chains that coil up into an alpha-helix. By contrast, the insoluble component, the amylopectin, is highly branched with additional bonds between shorter chain sections. Amylose can be specifically detected using iodine. Iodine is deposited inside the alpha-helix of the starch molecule. This results in a complex that has a distinctive color ranging from deep blue, blue-violet, to black, depending on the iodine concentration.

Information and ideas:
Glycogen, the storage for carbohydrates in animals, is comparable in structure to amylopectin.

Medientypen

Bild

Lernalter

16-18

Schlüsselwörter

Carbohydrate Metabolism Molecule Nutrition

Sprachen

Englisch

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

Bild

Lernalter

16-18

Schlüsselwörter

Fats Metabolism Molecule Nutrition

Sprachen

Englisch

Anderer Ressourcentyp

Siemens Stiftung

Ring closure with the glucose molecule

Simulation:
This is how a ring-shaped glucose molecule results from a glucose chain.

The glucose molecule is shown as its structural formula. The ring closure is shown in three steps. The last step, in which the ring is closed, is animated and can be stopped at any time by clicking "Pause".

Information and ideas:
For the sake of simplicity isomerism is not taken into account here.