Changing the case of one letter changes meaning dramatically

By MUNGAI KIHANYA

The Sunday Nation

Nairobi,

12 August 2018

A reader suggested that “since electricity is a critical part of modern living, the calculation of its cost should be included in the education system”. Well; if memory serves me right, we were taught how to do that in secondary school; but that was many decades ago!

I decided to check a few books to find out if this is still the case. The results were not very encouraging. The answer yes, the topic is in the syllabus, but some books have serious errors.

The form four Physics text book published by Jomo Kenyatta Foundation has a section titled: “kWH, consumption and cost of electrical energy”. This has fundamental error. Reading on, I discovered that it was not a simple typo – the mistake is carried on throughout the entire section.

Another form four physics book published by East African Educational Publishers has the following sentence in the table of contents: “The Kilowatt hour (kwh)….116”.

Again, this sentence has a fundamental error. Thankfully, in this case, the error is not carried on inside the main text of the book. So, I think it was a typo, but atill needs correction.

So, what is the error? It is the way these books abbreviate “kilowatt hour”: one writes “kWH” and the other “kwh”. As explained in this column in January 2015, scientific symbols follow strict nomenclature.

The symbol for watts is a capital “W” and that for hour is a small “h”. Therefore, kilowatt hour is abbreviated as “kWh”. The kWH in the Jomo Kenyatta Foundation book can only be read as kilowatt henry.

The henry – capital “H” – is the standard unit for measuring the inductance of an electrical coil. Thus, kilowatt henry (kWH) is a totally meaningless quantity and has absolutely nothing to do with calculating the amount of energy consumed by an appliance.

To my mind, there is no physical quantity in the universe whose symbol is a small “w”! So, the “kwh” in the East African Publishers book is also completely meaningless.

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With the ongoing demolitions of buildings deemed to be too close to the river, several readers have asked me how wide is the so-called “riparian zone” is. The Environmental Management and Coordination, (Water Quality) Regulations 2006 state that “no person shall cultivate or undertake any development activity within a minimum of six meters and a maximum of thirty meters from the highest ever recorded flood level, on either side of a river or stream, and as may be determined by the Authority from time to time.”

The big question is: how do the authorities determine if it is 6m or 30m or any number in between? Someone suggested to me that the zone is twice the width of the river, but subject to the stated limits.

Thus, if a stream is 1m wide, its riparian zone is 6m on either side; if it is 5m wide, the zone is 10m; and if it is 40m (like the Tana), the riparian will be 30m. Unfortunately, I cannot find any authoritative document to confirm this.