Very Interesting – July-August 2019

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or has the sand on a pebble beach

just been washed away?

Bernie Vorster, Southbroom

Beach material accumulates on

beaches during periods of accretion

and washes away during periods of

erosion. It’s made up of many sized

particles of different materials.

https://image.shutterstock.com/image-photo/electric-eel-electrophorus-electricus-

freTrevor loved
his new scalp
massager.

insight, as we dream, meditate or

otherwise have reduced

consciousness (4-8Hz).

Recording brainwaves can be

done in two different ways. An

electroencephalogram (EEG)

records brainwaves from the

scalp, while an

electrocorticogram (ECoG)

records from below the dura (one

of the three protective covers of

the brain).

You can even download an app to

improve or modulate brain

function by listening to various

sounds or beats. Google Play has

one called Brain Waves, which

gets great feedback.

And... charge!

Where and how are

brainwaves created?

John Kelly, Pretoria

The brain is an electrochemical

organ, home to roughly 100

billion cells. The individual cells

of our brains are called neurons

and communicate with each

other using electrical charges

called electro-chemical

signalling. Scientists have

theorised that a single brain

with all cells firing

simultaneously would provide

between five millionths and 50

millionths of a volt. Brainwaves

are also referred to as neural

oscillations and function differently

for different brain states.

• Alpha waves are soft and smooth
  and occur when we are physically
  and mentally relaxed (8-13Hz).


• Beta waves rise and fall more
  sharply and occur when we are
  conscious, thinking and alert or
  excited (13-32 Hz).


• Speedy Gamma waves follow
  sharp insights, learning or problem
  solving and cognitive processing
  (32-100Hz).


• Delta rhythms are slow and occur
  in deep, dreamless sleep (0.5-4Hz).


• Theta rhythms are slightly faster
  and occur with creativity and

sand. Waves can also be

constructive or destructive.

Constructive waves have a stronger

swash than backwash, so they

deposit material on a beach; while

destructive waves have a stronger

backwash and remove material

from the beach.

data from a company called Unique

Sims reported that the UK was onto

its final 40 million cell numbers.

Sources such as Tech Junkie have

estimated that the USA will still

have sufficient cell numbers for

another 30 years or so.

The general consensus is that new

codes can be created incorporating

an additional number, taking

numbers from 10 digits to 11 digits.

Hopefully our already struggling

networks will be able to cope with

the additional load.

Here we go a-grain

 When you visit different parts of

the world (or South Africa, for that

matter), you find fine sand, coarse

sand, shells or even pebbles – then

sometimes no sand at all, just

rocks and cliffs. Does that have to

do with the age of the beach and

long-term breaking down of rocks,

According to their size, shape and

weight, they get moved by wind,

waves or rain.

Two factors determine the size of

the grains of sand on a beach: the

height of the waves and the size of

the material being supplied to the

beach. A rule of thumb is the higher

the waves, the coarser the beach

Types of wave

CHARACTERISTIC CONSTRUCTIVE DESTRUCTIVE

Energy Low High

Swash Strong Weak

Backwash Weak Strong

Wave height Low High

Resulting beach shape Wide and flat Steep and narrow

Frequency Low, 6-8 per minute High, 10-14 per minute

An interesting factor is the size of the grain itself determines the slope of a beach. As a general rule, the

finer the sand the smaller the slope, and the coarser the sand the steeper the beach slope (slope is the

area between the high and low tide marks).