Education
Unit
: Senior High School
School
Name
: State Senior High School …
Subject
:
Chemistry
Class
/ Semester
: XI / second Semester
Learning
Materials
: Colloid
Allocation of Time : 2
x 45 minutes
5. Describe the system and the properties of colloid and its
application in daily life.
II. Basic Competence
:
5.1 To classify the properties of colloid and its
application in daily life
III. Indicator
1. Cognitive
1. Classify the types of colloid
systems based on dispersed phase and dispersing medium.
2. Describe the phenomenon of colloid
in daily life
2. Affective
Character skills :
Show an appreciation of scientific
attitudes such as . honest, responsibility,curiousity, passionate about
learning and open mindness.
IV. Learning Objectives:
A. Cognitive
1. After students do some observations,
students can classify the types of colloid systems based on dispersed phase and
dispersing medium.
2. Given some problems, students may
mention the role of colloid in cosmetics, foods, and pharmaceuticals.
B. Affective
Character skills :
Show an appreciation of scientific
attitudes such as . honest, responsibility, curiousity, passionate about
learning and open mindness.
V.
Learning Materials
Colloids are mixtures whose particles are larger than the size of a molecule
but smaller than particles that can be seen with the naked eye. Colloids are
one of three major types of mixtures, the other two being solutions and
suspensions. The three kinds of mixtures are distinguished by the size of the
particles that make them up. The particles in a solution are about the size of
molecules, approximately 1 nanometer (1 billionth of a meter) in diameter.
Those that make up suspensions are larger than 1,000 nanometers. Finally,
colloidal particles range in size between 1 and 1,000 nanometers. Colloids are
also called colloidal dispersions because the particles of which they are made
are dispersed, or spread out, through the mixture.ypes of lloids
Colloids are common in everyday life. Some examples include whipped cream,
mayonnaise, milk, butter, gelatin, jelly, muddy water, plaster, colored glass,
and paper.
Every colloid consists of two parts: colloidal particles and the dispersing
medium. The dispersing medium is the substance in which the colloidal particles
are distributed. In muddy water, for example, the colloidal particles are tiny
grains of sand, silt, and clay. The dispersing medium is the water in which
these particles are suspended.
Colloids can be made from almost any combination of gas, liquid, and solid. The
particles of which the colloid is made are called the dispersed material. Any
colloid consisting of a solid dispersed in a gas is called a smoke. A liquid
dispersed in a gas is deferred to as a fog.
|
Dispersed
Material
|
Dispersed
in Gas
|
Dispersed
in Liquid
|
Dispersed
in Solid
|
|
Gas
(bubbles)
|
Not possible
|
Foams: soda pop;
whipped cream; beaten egg whites
|
Solid
foams: plaster; pumice
|
|
Liquid
(droplets)
|
Fogs: mist;
clouds; hair sprays
|
Emulsions: milk;
blood; mayonnaise
|
butter;
cheese
|
|
Solid
(grains)
|
Smokes: dust;
industrial smoke
|
Sols and
gels: gelatin; muddy water; starch solution
|
Solid
sol: pearl; colored glass; porcelain; paper
|
Each type of mixture has special properties by which it can be identified. For
example, a suspension always settles out after a certain period of time. That
is, the particles that make up the suspension separate from the medium in which
they are suspended and fall to the bottom of a container. In contrast,
colloidal particles typically do not settle out. Like the particles in a
solution, they remain in suspension within the medium that contains them.
Colloids also exhibit Brownian movement. Brownian movement is the random zigzag
motion of particles that can be seen under a microscope. The motion is caused
by the collision of molecules with colloid particles in the dispersing medium.
In addition, colloids display the Tyndall effect. When a strong light is shone
through a colloidal dispersion, the light beam becomes visible, like a column
of light. A common example of this effect can be seen when a spotlight is
turned on during a foggy night. You can see the spotlight beam because of the
fuzzy trace it makes in the fog (a colloid).
VI. Learning Method:
Learning
Method: Demonstration, discussion, tasks giving
VII. Learning Activities
|
No
|
Teaching-Learning Activities
|
Allocation of
Time
|
|
A.
|
Introduction:
·
Teacher
starts the lesson by greeting, prayer, checking the attendance and
cleanliness of classroom
Engagement
phase
·
Teacher
demonstrates stirring detergent in water
·
Teacher asks
students, “what happens after I stirred the detergent in water?” and “why
there is foam in there?”. to grow up the curiousity of the students.
·
Teacher asks
students to mention the other similar phenomenon which have been demonstrated
·
Students are
guided to relate the phenomenon with the learning material which will be
learn.
|
5 minutes
10 minutes
|
|
2.
|
Core
activities
Exploration
Phase
·
Teacher
asks some questions about colloid :
ü Can you explain about colloid?
ü Do you know 2 components of
colloid?
ü Please explain the types of
colloids?
ü Do you know what colloid types of
fog, butter,dust and whipped cream?
·
Teacher guide the student to discuss each other about the question and the
answers
·
Students are guided to answer the question and contribute their
opinions and the others listen respectly the answer posed.
·
Teacher
asks each students to observe some colloids, and then classify the colloids
types based on its dispersed phase and dispersing medium.
·
Students
are guided to analyze and interpret their data
Explanation
Phase:
·
Teacher ask
each students to explain scientifically their observation data and their
conclusion
·
Teacher
gives chance to other students to ask some questions and respons about their
friends explanation.
·
Teachers
give the response for the students’ answers, and
re-explain or correct the answers
·
Provide
positive feedback and reinforcement in the form of oral, written, gesture, or
gift for all group’s answer
Elaboration
Phase:
·
Teacher
asks students to applicate colloid in another terms such as cosmetics, foods,
and pharmaceuticals.
Evaluation
Phase:
·
Students are
asked to answers evaluation sheet to know how far they learn the concepts of colloid
·
Teacher
guide students to do self evaluation
·
Students
are guided by the teacher to make the conclusion.
|
40 minutes
15 minutes
10 minutes
15
minutes
|
|
3.
|
The
final activity (Closing):
·
Teacher
gives students structure task to answer the questions in …
as homework and ask the student if they can collect it before next meeting.
·
Teacher gives
students unstructured task reading course about preparation of colloids
from … for next meeting
|
5 minutes
|
VII. Learning Tools
·
Whiteboard
·
Stationery
·
Power point contains about colloid and the procedure
of colloid
·
LCD
·
Milk, Parfume Sprayer, Ink, Hair Oil, Cheese,
Nail Polish, Lipstick, Detergent, Water
VIII. Learning
Resources
Guidelines
Scoring
|
No
|
Answer
|
Score
|
|||||||||||||||||||||||||||||||||||
|
1.
2.
|
·
Industrial
food: butter, milk, gelatin, spices lettuce, cheese, bread
·
Cosmetics:
perfumes, deodorant spray, liquid to mask, nail polish, facial cleansing milk
and skin, deodorant stick, hair oil (jelly), shaving soap, beauty soap,
lipstick, eyebrow pencil, mascara
·
Pharmacy:
syrup, medicine, capsule
|
3
2
3
3
2
3
3
3
3
|
Evaluation Sheet
1. Complete the table below
|
No
|
dispersed phase
|
dispersing medium
|
Colloid types
|
Example
|
|
1
|
Sol
|
|||
|
2
|
Gas
|
Liquid
|
||
|
3
|
Smoke
|
|||
|
4
|
Alloys
|
|||
|
5
|
Liquid
|
Gas
|
||
|
6
|
Emulsion
|
2. Describes 3 examples of colloid in terms of cosmetic
industry, foods industry and pharmaceutical!
Key of Evaluation
Sheet
1.
|
No
|
dispersed phase
|
dispersing medium
|
Colloid types
|
Example
|
|
1
|
Solid
|
Liquid
|
Sol
|
mud
|
|
2
|
Gas
|
Liquid
|
Foam
|
Whipped Cream
|
|
3
|
Solid
|
Gas
|
Smoke
|
Dust
|
|
4
|
Solid
|
Solid
|
Solid Sol
|
Alloys
|
|
5
|
Liquid
|
Gas
|
Liquid Aerosol
|
Fog
|
|
6
|
Liquid
|
Liquid
|
Emulsion
|
Milk
|
2. Three examples of colloid in terms of cosmetic
industry, foods industry and pharmaceutical:
·
Industrial
food: butter, milk, gelatin, spices lettuce, cheese, bread
·
Cosmetics:
perfumes, deodorant spray, liquid to mask, nail polish, facial cleansing milk
and skin, deodorant stick, hair oil (jelly), shaving soap, beauty soap,
lipstick, eyebrow pencil, mascara
·
Pharmacy:
syrup, medicine, capsule
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