Part of Speech

Nouns are simily refered to as Naming words.Nouns name things e can ee a well as things we cannot see. Types of nouns include:
Proper nouns; are the names of people, places, organizations, days, months, or titles.
Abstract nouns; describe qualities or states of being.
Common nouns; are names used for general classes of people, places, or things.
Collective nouns; are names used for groups of animals, people, or things. eg. a herd of cattle,

Verbs are action words. They also show being or apperance. Verbs can take various forms like nouns and the form they take is determined by who is doing the action and when the action occurred.
Example: You play football every Sunday. The word ‘play is the verb and it i an action word.
Example of verbs showing being or appearance include: ‘is’ ‘be’, ‘becomes’, ‘seem’, ‘were’ and ‘appear’
eg. My brother is very fit.
We were happy yesterday.
Tense, in English is used to indicate time something occurred or will occur. There are even tense in English;
i. Present
ii. Present perfect
iii. Present continuous
iv. Future
v. Future perfect
vi. Past
vii. Past perfect

When the action is happening now.. eg. She walks on the pavement. It is called present tense.
When the action was completed in the past.. eg. she walked on the pavement. It is called past tense.
When the action started in the past and has continued.. eg. She has walked on the pavement. it is called present perfect tense.
When the action occurred in the past before an action that also occurred in the past.. eg. She had walked on the pavement. It is called past perfect tense.
When the action will occur in the future.. eg. She will walk on the pavement. It is called future tense.
When the action will be completed by some time in the future.. eg. She will have walked on the pavement. It is called future ferfect tense.
If the action is continuing in the present.. eg. She is walking on the pavement. It is called present continuous tense.
Type of verbs
Auxiliary verbs; include, ‘do’, ‘me’ and ‘have’
Main verbs ; include, eat, talk, drink, walk etc. eg. we walk together. Talk to him.

Adjectives are words that discribe the quality or tell us something about a noun or pronoun.
eg. 1. Nice girl

2. Bad friend

3. Sweet potatoe
Adjectives come in 3 forms; they are:
i. positive
ii. comparative
iii. superlative
The positve form just states the quality, the comparative form compares the quality of two things while the superlative compares the quality of 3 or more things
Positive : My car is neat.
Comparative: My car is neater than yours.
Superlative: My car is the neatest.

Adverbs modify verbs and usually end in – ly, but there are exceptions. adverbs also modify other adverbs and adjectives.
adverbs answer questons such as how?, how often? where? when?, they also show time , space and manner.
I need to run quickly if i’m to get there first.
Sola can drive the car really well

Preposition is a word used to show the relationship of nouns, pronouns or other words in a sentence. preposition cab tell time, position and means.
we should meet by 12pm.
I was at school all day
I traveled by car to Oyostate.
Common prepositions are: about, above, across, after, along, among, around, as, at, before, behind, below, beneath between, by, concerning, despite, during, for, from, into, like, of, off, outside, past, regarding, since, till, to, under, until, with.

Pronouns are used in place of nouns to avoid repetition. The three main types of pronouns are, personal,relative and indefinite pronouns.
Personal pronouns
Relative pronouns
Indefinite pronouns


Punctuation is used to make sense of what we read. It is used to convey the true meaning of what we write. punctuation is about how words relate to each other. it helps us know when to pause, stop, become exited, lift voice etc within a sentence. it also helps us know when to begin a sentence.

Punctuation marks.

Full stop (.)

Full stop ends a sentence. It is also used at the end of an abbreviation.

Comma (,)

Comma is used to separate words, clauses or phrases. It is also used to indicate a short pause withing a sentence. Commas are used to separate independent statements which are linked by; for, and,nor,but,or,yet and so.

Semi colon (;)

Words that need a stronger pause within a sentence requires a semicolon. example of words used after semicolon is; however, therefore, also, more over, furthermore, have, separately and consequently.

Colon (:)

Colons is used to introduce new information within a sentence. It can also be used before quotations or a list of things. colons makes the reader focus on whats happening next as he reads on.

Apostrophes (‘)

Apostrophe is used to show possession or ownership.

Speech marks (” “)

Are quotation marks used to record what somebody has said.

Exclamation mark (!)

The exclamation mark gives a lot of oomph. it tells us if a statement or work is made in anger or disgust.

Question mark (?)

It is put at the end of a sentence or word to indicate that it is a question.

Ellipsis (…)

An ellipsis is used to show that the writer has left something out deliberately.

Asterisk (*)

Asterisk is used to replace letter or words within a sentence. often used to replace letters of words that are too vulgar to pronounce.

Bullet points ()

It is used to tell us important points of what we are reading.

Stroke or Forward slash (/)

It is used to tell us that we have a choice to make or that we are reading lines of poetry

Hydroelectric Power Systems

hyro electric dam
Hydro electric dam

Hydroelectric power plants convert potential and kinetic energy of water into electricity.

In hydroelectric production, potential energy of water is created by the construction of large dams. The dams hold the water at a greater height than the water level at the turbines.

Water is the greatest contributor of renewable energy to the world electricity generating system.

The common unit of measurement used to indicate the installed capacity of a hydroelectric power station is Megawatts.

Types of hydroelectric power plants

Based of design, hydro electric power plants are broadly divided into 2 types;

  1. Impoundment power plant
  2. Diversion power plant.

In the impoundment type of power plant, All water coming into the plant is dammed. The dammed water creates the head needed to power the hydro plant.

Impoundment  type of Hydro dam
Impoundment type of Hydro dam

In the diversion type, the water coming to the plant is partially dammed, some water is allowed to flow back into the river immediately while the rest is used to power the hydro plant.

Head and tail water

 In a hydro power plant system, the dammed water upstream is known as Head water and the water on the other side of the dam is known as Tail water. The difference between the top of the head water and that of the tail water is called pressure head.

Components of hydroelectric power plant

Trash rack; when water is coming fresh from the dam it needs to be cleared of big debris such as wood , plastic bags etc. the duty of the trash rack is to remove these.

Inlet gate; after water have been processed to remove debris, it then passed through the inlet gate. The inlet gate is used to regulate water flow into the turbines

Water conductors; water conductors are equipment used to convey water within the hydo electric power system. Example include; penstock, draft tube, scroll case, spill way, canals etc.

Penstock; the main pipe that conveys water to the turbine is known as penstock. It is a pressurized water conductor.

Spill way;  a spillway is a water conductor used to prevent overflow of dammed water

Runner; the runner is part of the turbine system and it rotates as water from the penstock passes through it at high pressure

Power house; the power house houses the turbine, electric generators, transformers and other electric generating equipment

Open air switch yard; when the electrical transmission equipment is installed in open air, it is called an open air switch yard.

How a hydroelectric turbine works

Water with high pressure head on the upstream side of the dam is lead through large penstock pipe. Before the water get to the turbine it passes through a scroll case. The scroll case is a large curved pipe that helps the flowing water to efficiently rotate the turbine. The turbine is connected to the generator through a shaft. so  as the turbine rotates, the connected generator also rotates  producing electricity.

Advantages of hydroelectric power plant.

  1. It is a completely green process
  2. It is a very efficient way of generating electricity.

Disadvantages of hydroelectric power plant

1. It is always necessary for settlement around the dammed area relocate. This is because water required to run hydroelectric plants is extremely large and dammed water will cause flooding of the settlement.

2. It is capital intensive. This is because the hydro dams constructed are extremely large.

Types of hydro power plants

  1. Impoundment type power plant. This type of power plant utilizes a dam to impound large amount of flowing river water. The dammed water is the potential energy necessary to power the hydro plant. The different type of dams that could be used include; gravity, reinforced concrete, buttress, rock filled or earth dams.
  2. Diversion type power plant( run of the river). In this case, the river water is partially dammed, only part of the flowing water is utilized to produce electricity.
  3. Tidal water plant. This process works based on tidal action of water. it helps create a height difference on either side of the turbine, this pressure difference cause water to flow through the turbine rotating it.
  4. Pumped storage power plant. This type of plant basically consists of very large reservoir of water held at a very high level. The stored water is then made to flow downwards through a penstock pipe to run the turbine and generate electricity. After reservoir is depleted, the water is pumped back again and the whole process is repeated. Pumped storage power plant is a type of standby power generator.Its acts as a supplement and is usually made available to the national grid during peak hours

Types of turbines

Broadly of two types;

  1. Reaction turbine
  2. Impulse turbine

The reaction turbine are pressure turbines. When water flow through this turbine, it creates a pressure differential which causes the turbine to rotate.

Impulse turbine are pressure-less turbines. It rotates due to the kinetic energy given to it by a jet of water as its hits the blades.

Types of turbine runners

There are many types of turbine runners, however, the 3 most commonly used are;

  1. Kaplan runner
  2. Francis runner
  3. Pelton runner

Kaplan runners are types of turbine runners that can operate with medium to high water flows and efficient at low pressure heads. Kaplan runners are reaction  runners because the pressure difference of the water flowing through the blades causes it to rotate.

Kaplan runner
Kaplan runner

Francis runners  are reaction runners and can operate within a wider range of pressure heads than the Kaplan runners.

Francis runner
Francis runner

Pelton runners are only adequate for very high flows and operates within a narrower range compared to the Kaplan and Francis runners.

pelton runner
Pelton runner