Applied Sciences

Spectral investigations

Principle

An echoscope is used to investigate the difference between a spectrum produced by a pulse and a spectrum produced by a periodic signal using multiple reflections from a block. The periodic spectrum allows the cepstrum (Fourier transform of the log spectrum) to ...

Metallographic sample preparation - grinding and polishing

Metallographic sample preparation - chemical etching

Ideal add to P5011100, polishing equipment required

Principle

Chemical etching is the most common method for contrasting polished metalsurfaces to reveal structural details of pure metals and alloys. The precondition for a good result in etching is a carefully p ...

Membrane filter method

Sound perception and sound level measurement

Image inversion and accommodation

Myopia - Hyperopia

Electronystagmography

Principle

Electronystagmography (ENG) is an electrophysiological diagnostic procedure for measuring the movement of the eyes. Several electrodes measure the potential differences that are caused by the eye movements. When looking at a moving, regular, repetiti ...

Hill reaction

Dependence of the soil temperature on the structure and wa-ter content of the soil

Principle

This experiment covers the separation and analysis of traces of sand, clay and humus in soil. These substances, both mineral and organic, appear in various types of soil and have a major effect on soil properties. The quantity of humus is the basis for the ...

Humidity preferendum of soil arthropods

Principle

Heat radiated by a lamp gradually causes soil to dry out. That and the light emitted cause any creatures in a sample to burrow to the bottom where they are sieved into a funnel and collected inside a vessel. The vessel contains moist filter paper in order to capture ...

Electrometric determination of dissolved oxygen in water

Hydrogen ion concentration of water

Water purification by filtration with active carbon

Principle

Active carbon is a good absorbent and as such is excellent when used as a filter. During water treatment, for example, active carbon filters are used to remove pesticides and detergents (soap and washing-up liquid). The cleansing of water can be demonstrated im ...

Air pollution through uncontrolled waste burning