DEPARTMENT OF EDUCATION

NATIONAL CAPITAL REGION

Daily Lesson Log

School RIZAL HIGH SCHOOL Grade Level GRADE 9

I. OBJECTIVES
The learners demonstrate understanding of the ff:
A. Content
1. the relationship among heat, work, and efficiency
Standards
B. Performance 1. analyze how power plants generate and transmit electrical energy
Standards
The learners should be able to:
1. construct a model to demonstrate that heat can do work (S9FE-IVe-42);
2. infer that heat transfer can be used to do work, and that work involves the release
of heat(S9FE-IVf-43);
3. explain why machines are never 100-percent efficient (S9FE-IVf-44);
C. Learning 4. explain how heat transfer and energy transformation make heat engines like
Competencies/ geothermal plants work (S9FE-IVf-45).
Objectives Specific objectives:
At the end of the teaching - learning process, at least 75% of students should be able to:
a. Determine what heat engine is.
b. Discuss the four cycle stroke of a gasoline engine.
c. Appreciate the importance of heat engine in our daily living.
with at least 75% mastery level.
II. CONTENT Heat Engine and Thermal Efficiency
III. LEARNING
RESOURCES
A. References
1. Teacher’s Guide 273 – 275
pages
2. Learner’s Manual 362 – 370
pages
3. Textbook pages
4. Additional Materials 1. www.youtube.com
from Learning 2. www.google.com
Resource (LR) 3. www.slideshare.com
portal
B. Other Learning
Resources
IV. PROCEDURES
A. REVIEW : Reviewing 1. Why a can of soft drink remains at a constant cool temperature inside a refrigerator?
A. Because the amount of heat flowing into the can is exactly equal to the heat flowing out.
previous lesson or B. Because the amount of heat flowing into the can is greater than the heat flowing out.
presenting new lesson C. Because the amount of heat flowing into the can is less than to the heat flowing out.
D. Because the amount of heat flowing into the can could not be determined since there is no temperature installed in the
refrigerator.
2. The internal energy of a system is initially 35J. The system does 34J of work. What is the system’s final internal energy
when a total of 46J of energy is added to the system by heat?

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 A. 47J B.26J C.37J D.36J
3. A block of wood and a block of metal is on a table for a long time. The block of metals feels colder to the touch than the
block of wood. Does this mean that the metal is actually at a lower temperature than the wood?
A. Yes, because the heat flow more readily in denser material.
B. Yes, because the heat flow whenever it wants to flow.
C. No, because the heat flow more readily from your hand than for wood.
D. No, because the heat flow less readily from your hand than for wood.
4. When you touch a cold piece of ice with your finger, which is the correct direction of energy flows?
A. From the ice to your finger C. from your finger to the ice
B. Either both ways D. both A and B
5.What is the process of compression and expansion of gas so that no heat enters or leaves the system?
A.Adiabatic B.Isothermic C.Isobaric D. Thermal expansion
B. MOTIVATION: Previously, you were asked if heat can be converted into work. Do you know that there is a device that can do these, It is
known as heat engine. Let us find out how heat engine converts heat into work.
Establishing a purpose
of the lesson
C. PRE-ACTIVITY: 1. Giving directions and precautions.
Presenting examples/
instances of the new
lesson
D. ACTIVITY PROPER: Answering Activity 4: Start the engine
Discussing new Activity 5: Fill me in!
concepts and practicing
new skills
E. DEEPENING: 1. Discussion of the result of the activity
Discussing new
concepts and practicing
new skills
F. POST ACTIVITY: Exercises/ problem solving applying the equations on Thermal Efficiency
Developing mastery
G. APPLICATION: 1. What are the devices or technology that we are using everyday uses the heat engine?
Finding practical
applications of concepts
and skills in daily living
H. GENERALIZATION: A device that changes thermal energy into mechanical work is a heat engine.
Making generalizations There are two kinds of heat engines; internal and external combustion engine.
and abstractions about They are classified according to where the combustion takes place.
the lesson If the fuel is combusted inside the engine chamber, it is an internal combustion engine.
When the fuel combustion takes place outside the engine, it is an external combustion engine.
Gasoline, diesel engine and our human body are examples of internal combustion engine while steam, piston
engine and the atmosphere are examples of external combustion engine.

Cycle stroke Movement of the piston What happened to mixture of gases?

Intake Moves down Filled in the cylinder

Compression Moves upward Compressed into fractional amount

Power Moves down Ignited by the spark plug

Exhaust Moves up Expelled out by the exhaust pipe

Thermal Efficiency

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 It was thought before the full understanding of the second law of thermodynamics that at very low friction
heat engine could convert nearly all the input energy into useful work. It was then that Sadi Carnot carefully
studied the compression and expansion cycles. It is found out that the upper fraction of heat that can be
converted to useful work, even under the ideal conditions.

How well a machine operates is the ratio of the useful work done to the heat provided is the thermal efficiency.
In equation, it is expressed in
.
Efficiency = Wnet/ QH x 100%
Efficiency = QH – QC/ QH x 100%
Efficiency = 1- QC/ QH x 100%
Or
Efficiency = 1- energy removed by heat / energy added by heat x 100%
If we have ideal engine, it would be
Maximum Efficiency = 1= TC/TH
Where;
QC = energy removed by heat/energy in cold reservoir
QH = energy added by heat/energy in hot reservoir
TC = absolute temperature in cold reservoir
TH = absolute temperature in hot reservoir
Note: The temperatures are the absolute temperatures is on the Kelvin scale.
Studying our equation, we can only have a 100% efficiency if there is no energy transferred away from the
engine by heat. But in reality, there is no 100% efficient engine. In addition, the equation tells us that by
increasing the amount of energy added to the system by heat or by reducing the amount of energy given up
by the system.
I. ASSESSMENT: 5 items short quiz
Evaluating learning
J. REMEDIAL: Additional
activities for application
or remediation
V. REMARKS
VI. REFLECTION
A. No. of learners who 9-7 9-8 9-9 9-10 9-11
earned 80% on the
formative assessment
B. No. of learners who
require additional
activities for remediation
C. Did the Remedial lesson
work? No. of learners
who have caught up with
the lesson
D. No. of learners who
continue to require
remediation
E. Which of my teaching
strategies worked well?
Why did these work?
F. What difficulties did I
encounter which my
principal or supervisor
can help me solve?
G. What innovation of
localized materials did I
use/discover which I
wish to share with other
teachers?

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Quiz:
1. Is it possible to change the temperature of a glass of water by stirring the water, even though the glass is insulated from its surroundings?
A.No, stirring will not affect the temperature of the water.
B.No, insulation prevents the change of temperature of the water.
C. Yes, stirring the water increases its internal energy causing the increase of its temperature.
D. Yes, stirring the water decreases its internal energy causing the decrease of its temperature.
2. Mang JM, a carpenter, is planning a piece of wood with his planar. After how many minutes, he observed that it is hot. Do the wood gained heat?
A. No, it is not evident.
B. Yes, hotness means there is an increase in the temperature.
C. Yes, hotness means there is a decrease in the temperature
D. No, hotness is not related to a change in temperature
3.How does water from the deep well move upward?
A. It occurs naturally.
B.It uses heat pump.
C. It is a spontaneous process.
D. It flows from higher temperature to cooler temperature.
4. What is the function of a heat engine?
A. It converts chemical energy to mechanical energy.
B. It converts thermal energy to mechanical energy.
C. It converts mechanical energy to chemical energy.
D. It converts thermal energy into chemical energy.
5.What is the correct sequence of four cycle-stroke of gasoline engine?
1. Intake 3. Exhaust
2. Power 4. Compression
A. 1,2,3,4 B. 1,4,2,3 C.2,3,4,1 D.1, 3,4,2

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