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Natural sciences

Energy transfers and forces

Educator section

Memorandum

(a) Petrol – motor-car

Gas – stove

Coal – steam locomotive

Wood – fire to provide heat

Crude oil – aeroplane fuel is derived from it

(b) Wind-propelled devices – wind farm

Engines that move by means of used cooking-oil

Solar heating for warmth

(c) Advantages and disadvantages of nuclear fuels and fossil fuels.

(i) Fossil fuels

Advantages Disadvantages
Quite readily available. Causes air pollution – emits smoke and harmful gases.
Can easily be converted to energy. Presents a fire hazard.
Relatively inexpensive. Mining defaces the environment.

(ii) Nuclear fuels

Advantages Disadvantages
A great deal is available. Health risks caused by radioactive eradiation.
Minimal pollution of the environment. Energy must be transported over long distances, seeing that power stations have to be built near the coast because of the water cooling systems that are used.
A small amount produces a great deal of energy. Radioactive waste must be stored safely for years until the radioactivity disappears.

Leaner Section

Content

Activity 4: to list fuels and their uses [lo 1.3]

(a) Name five common fuels and one use of each:

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(b) It is very important for people to find other sources of energy. Try to suggest ways in which people can use energy differently or make use of other sources, e.g. electric cars.

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(c) Name three advantages and three disadvantages of:

(i) Fossil fuels

ADVANTAGES DISADVANTAGES
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(ii) Nuclear fuels

ADVANTAGES DISADVANTAGES
1.___________________________________________________________ 1.___________________________________________________________
2.___________________________________________________________ 2.___________________________________________________________
3.___________________________________________________________ 3.___________________________________________________________

(d) Consider the sources of energy that we have been discussing and then draw up a list to show how you could conserve energy, e.g. by switching off the lights in the classroom when the sun is shining.

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4. forms of energy

The human body does not use fuel (food) in the form in which we take it. The food is broken down into simple substances that are conserved in the muscles, in the particular form that can be used by the muscles. There therefore is energy in the substances that are stored in the muscles. Energy that is stored in chemical substances like food and fuel is known as chemical energy. All fuels therefore contain chemical energy.

Chemical energy is released when some reaction occurs. If coal is burnt, for instance, it releases heat that can then be used to generate steam for a steam locomotive.

Heat energy is used every day. We need it to cook our food and to keep warm.

Heat energy boils the water in the locomotive’s kettle and this forms steam.The steam drives the locomotive.

The sun provides us with light, as do fuels and electricity. When electricity flows through the filament in a light bulb, the wire is heated and glows. It releases light energy , as well as a small amount of heat energy. Some worms, fireflies and fish also radiate light energy.

Kinetic energy results from movement. Moving water can turn a water wheel, while wind can drive a wind pump.

Energy that is stored in things and waiting to be released by some means or other is called potential energy. The spring of an air gun that is loaded has the ability to fire. We therefore say that the loaded spring has potential energy.

Assessment

Learning Outcome 1: The learner will be able to act confidently on curiosity about natural phenomena, and to investigate relationships and solve problems in scientific, technological and environmental contexts.

Assessment Standard 1.3: We know this when the learner evaluates data and communicates findings: generalises in terms of relevant aspects and describes how the data support the generalisation.

Questions & Answers

explain and give four Example hyperbolic function
Lukman Reply
The denominator of a certain fraction is 9 more than the numerator. If 6 is added to both terms of the fraction, the value of the fraction becomes 2/3. Find the original fraction. 2. The sum of the least and greatest of 3 consecutive integers is 60. What are the valu
SABAL Reply
1. x + 6 2 -------------- = _ x + 9 + 6 3 x + 6 3 ----------- x -- (cross multiply) x + 15 2 3(x + 6) = 2(x + 15) 3x + 18 = 2x + 30 (-2x from both) x + 18 = 30 (-18 from both) x = 12 Test: 12 + 6 18 2 -------------- = --- = --- 12 + 9 + 6 27 3
Pawel
2. (x) + (x + 2) = 60 2x + 2 = 60 2x = 58 x = 29 29, 30, & 31
Pawel
ok
Ifeanyi
on number 2 question How did you got 2x +2
Ifeanyi
combine like terms. x + x + 2 is same as 2x + 2
Pawel
Mark and Don are planning to sell each of their marble collections at a garage sale. If Don has 1 more than 3 times the number of marbles Mark has, how many does each boy have to sell if the total number of marbles is 113?
mariel Reply
Mark = x,. Don = 3x + 1 x + 3x + 1 = 113 4x = 112, x = 28 Mark = 28, Don = 85, 28 + 85 = 113
Pawel
how do I set up the problem?
Harshika Reply
what is a solution set?
Harshika
find the subring of gaussian integers?
Rofiqul
hello, I am happy to help!
Shirley Reply
please can go further on polynomials quadratic
Abdullahi
hi mam
Mark
I need quadratic equation link to Alpa Beta
Abdullahi Reply
find the value of 2x=32
Felix Reply
divide by 2 on each side of the equal sign to solve for x
corri
X=16
Michael
Want to review on complex number 1.What are complex number 2.How to solve complex number problems.
Beyan
yes i wantt to review
Mark
use the y -intercept and slope to sketch the graph of the equation y=6x
Only Reply
how do we prove the quadratic formular
Seidu Reply
please help me prove quadratic formula
Darius
hello, if you have a question about Algebra 2. I may be able to help. I am an Algebra 2 Teacher
Shirley Reply
thank you help me with how to prove the quadratic equation
Seidu
may God blessed u for that. Please I want u to help me in sets.
Opoku
what is math number
Tric Reply
4
Trista
x-2y+3z=-3 2x-y+z=7 -x+3y-z=6
Sidiki Reply
can you teacch how to solve that🙏
Mark
Solve for the first variable in one of the equations, then substitute the result into the other equation. Point For: (6111,4111,−411)(6111,4111,-411) Equation Form: x=6111,y=4111,z=−411x=6111,y=4111,z=-411
Brenna
(61/11,41/11,−4/11)
Brenna
x=61/11 y=41/11 z=−4/11 x=61/11 y=41/11 z=-4/11
Brenna
Need help solving this problem (2/7)^-2
Simone Reply
x+2y-z=7
Sidiki
what is the coefficient of -4×
Mehri Reply
-1
Shedrak
the operation * is x * y =x + y/ 1+(x × y) show if the operation is commutative if x × y is not equal to -1
Alfred Reply
A soccer field is a rectangle 130 meters wide and 110 meters long. The coach asks players to run from one corner to the other corner diagonally across. What is that distance, to the nearest tenths place.
Kimberly Reply
Jeannette has $5 and $10 bills in her wallet. The number of fives is three more than six times the number of tens. Let t represent the number of tens. Write an expression for the number of fives.
August Reply
What is the expressiin for seven less than four times the number of nickels
Leonardo Reply
How do i figure this problem out.
how do you translate this in Algebraic Expressions
linda Reply
why surface tension is zero at critical temperature
Shanjida
I think if critical temperature denote high temperature then a liquid stats boils that time the water stats to evaporate so some moles of h2o to up and due to high temp the bonding break they have low density so it can be a reason
s.
Need to simplify the expresin. 3/7 (x+y)-1/7 (x-1)=
Crystal Reply
. After 3 months on a diet, Lisa had lost 12% of her original weight. She lost 21 pounds. What was Lisa's original weight?
Chris Reply
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Source:  OpenStax, Natural sciences grade 7. OpenStax CNX. Sep 16, 2009 Download for free at http://cnx.org/content/col11077/1.1
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