HND 2nd Year Interview Briefing
RADIATION & ELECTRICAL CURRENTS
The Electromagnetic Spectrum consists of a range of electromagnetic waves with
differing wavelengths and frequencies that travel without a medium and at the same
speed.
The diagram below shows the spectrum with the varying radiations
NB The shorter the wavelength the more dangerous it is
Infra Red Radiation
Infra-Red rays are electromagnetic waves with wave lengths between 700 nm and
400,000 nm. They are emitted naturally from the Sun as well as from hot objects –
electric fires, coal fires, hot packs, special heater lamps as well as you!
Infrared is split into 2 different types:

Luminous Infrared (700 – 1400nm ) is nearest to the visible part of the
spectrum (shortest wavelength, therefore more penetrating to the skin)

Non Luminous Infrared (greater then 1400nm) is furthest from the visible
part of the spectrum (longest wavelength, therefore less penetrating to the
skin)
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Ultra Violet Radiation
Ultraviolet has a shorter wavelength than visible light and is invisible to the naked
eye and although it only forms 3% of light from the sun it is one of the most
damaging parts of the spectrum
There are 3 types of UV radiation:

UVA:o Longest Wavelength
o Is necessary for healthy growth – Vit D
o Causes premature ageing – penetrates into the dermis causing
fragmentation of the collagen and elastin fibres
o Produces short term tan – stimulates existing melanin

UVB:o Mid range Wavelength
o Produces suntan and sunburn
o Sunburn – penetrates to the epidermis, will cause permanent
damage to the skin – body responds by realising histamine from the
skin’s cells, resulting in dilation of blood vessels allowing more
blood to reach the epidermis = erythema
o Produces long term tan - stimulates melanocytes to produce
new melanin
o Overexposure can lead to skin cancer

UVC:o Shortest Wavelength
o Lethal to all organisms – converts oxygen to ozone
o UVC is filtered out by the Ozone layer around the earth
o UVC causes skin cancer
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Electrical Current:
Electrical Current is the flow of electrons from a negative terminal to a positive
terminal through a substance
Direct Current:


current that is flowing in one direction only such as from a battery
electrons flow from negative electrode to the positive electrode
Alternating Current:

current that is alternating direction, i.e. its direction of flow changes
regularly, in Britain this is 50 Hz or 50 cycles per second (frequency),
normally from a generator
:
Faradic Current:

a current that is produced from a direct current which is rapidly switched
on and off (interrupted direct current). These signals have a relatively
low frequency in the range of 10 to 120 hertz
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Currents in Electrolytes
Another material which is good at conducting electricity is a solution of ions (e.g.
NaCl (salt) dissolved in water) known as an electrolyte



an electrolyte is a solution which contains ions – this includes human
tissue
cations (positive ions  attracted to cathode, i.e. the negative electrode)
anions (negative ions  attracted to anode, i.e. the positive electrode)
Uses of Electrical Current in Beauty Therapy Electrical current is used in many forms within the Beauty Industry due to their
varying properties and effects –
GALVANIC: (Direct Current)
o Direct Current = electrons/ions flow from –ve to +ve in the same
direction round the circuit at all times
o Requires a constant current to prevent a tingling sensation during the
treatment
o Creates a movement of ions
o Breaks down the skin’s resistance due to a chemical reaction
To carry out a galvanic treatment you need:


Active Electrode - applies the current to the client’s skin
Indifferent Electrode - completes the circuit
Application:

Iontophoresis – repulsion of ions with similar polarity active electrode is
dependent on the polarity of the product used

Desincrustation – polar effects of alkali formation (Sodium
Hydroxide) therefore active electrode is always the negative

Electrolysis – chemical destruction of tissues of the hair follicle using caustic
soda - active electrode is always Cathode, shaped as a fine needle which is
inserted into the hair follicle until it reaches the hair papilla where the moisture
is converted to caustic soda
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FARADIC: (Interrupted Direct Current ie a direct current which is rapidly switched
on and off)
Current must be interrupted to allow the muscle to adapt to the current. (This is
sometimes called accommodation) – the motor nerves of the muscle is stimulated
resulting in a contraction therefore toning the muscle. A constant flow of current will
not produce a contraction as the muscle will not have adapted

Uses
o
o
o
o
Correction of figure faults
Tones undertone muscles
Girth reduction
Alteration of body contours
HIGH FREQUENCY: (Alternating Current )- electrons flow one way around the
circuit and then reverse direction and flow back the other way
Produces a warming of the tissues by ‘exciting or vibrating’ the water molecules
within the tissues
Only one electrode is needed – no indifferent needed as circuit is complete through
the client to earth
Application:
There are 3 ways of applying High Frequency in beauty treatments

Direct :–
o uses a selection of glass electrodes for a germicidal effect
o Gauze can be used to increase the germicidal effect due to the gap
produced between the gauze and skin creating sparks

Indirect –
o client holds a saturator electrode and the therapist gives a massage
o Current flows from the electrode through the client towards
therapist’s hands then back to earth
o Warmth is created under the therapist’s hands directly on the client’s
skin
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
Shortwave Diathermy (thermolysis): –
o the current is applied through a fine needle inserted into the hair
follicle for a short period of time
o The heat that is produced brings about the destruction of the
lower follicle
o A much quicker process than Electrolysis but not as successful
as it cannot treat curved or distorted follicles well
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