Teacher-made Learner’s Home Task
School: Pilar National High School Date: October 2, 2020
Grade/Section: Grade 7-Aguinaldo, Macapagal Subject Area/s: Science 7
I. MELC: express concentration of solutions quantitatively by preparing different
concentration of mixtures according to uses and availability of materials S7MT-Ig-6
II. Objective/s:
a. Knowledge: identify greenhouse gases and its composition in the atmosphere
b. Skills: explain how the concentration of greenhouse gases in the atmosphere
affect the earth
c. Values/Attitude: understand the concept of greenhouse effect and how
humans contribute to the increase of greenhouse gases
III. Subject Matter: Concentration of Gases: Greenhouse Gases and Greenhouse Effect
IV. References:
https://www.massaudubon.org/our-conservation-work/climate-change/why-
we-care/greenhouse-gases
https://www.epa.gov/ghgemissions/overview-greenhouse-gases
https://www.brainpop.com/science/earthsystem/greenhouseeffect/quiz/print
.pdf
IV. Procedure:
A. Readings
GREENHOUSE GASES AND THE GREENHOUSE EFFECT
Gases that trap heat in the atmosphere are called greenhouse gases.
Carbon dioxide (CO2): Carbon dioxide enters the atmosphere through
burning fossil fuels (coal, natural gas, and oil), solid waste, trees and other
biological materials, and also as a result of certain chemical reactions (e.g.,
manufacture of cement). Carbon dioxide is removed from the atmosphere
(or "sequestered") when it is absorbed by plants as part of the biological
carbon cycle.
Methane (CH4): Methane is emitted during the production and transport
of coal, natural gas, and oil. Methane emissions also result from livestock
and other agricultural practices and by the decay of organic waste in
municipal solid waste landfills.
Nitrous oxide (N2O): Nitrous oxide is emitted during agricultural and
industrial activities, combustion of fossil fuels and solid waste, as well as
during treatment of wastewater.
Fluorinated gases: Hydrofluorocarbons, perfluorocarbons, sulfur
hexafluoride, and nitrogen trifluoride are synthetic, powerful greenhouse
gases that are emitted from a variety of industrial processes. Fluorinated
gases are sometimes used as substitutes for stratospheric ozone-depleting
substances (e.g., chlorofluorocarbons, hydrochlorofluorocarbons, and
halons). These gases are typically emitted in smaller quantities, but
because they are potent greenhouse gases, they are sometimes referred to
as High Global Warming Potential gases ("High GWP gases").
Each gas's effect on climate change depends on three main factors:
How much is in the atmosphere?
Concentration, or abundance, is the amount of a particular gas in the air.
Larger emissions of greenhouse gases lead to higher concentrations in the
atmosphere. Greenhouse gas concentrations are measured in parts per
million, parts per billion, and even parts per trillion. One part per million
is equivalent to one drop of water diluted into about 13 gallons of liquid
(roughly the fuel tank of a compact car). To learn more about the
increasing concentrations of greenhouse gases in the atmosphere, visit the
Climate Change Indicators: Atmospheric Concentrations of Greenhouse
Gases page.
How long do they stay in the atmosphere?
Each of these gases can remain in the atmosphere for different amounts of
time, ranging from a few years to thousands of years. All of these gases
remain in the atmosphere long enough to become well mixed, meaning
that the amount that is measured in the atmosphere is roughly the same
all over the world, regardless of the source of the emissions.
How strongly do they impact the atmosphere?
Some gases are more effective than others at making the planet warmer
and "thickening the Earth's blanket."
For each greenhouse gas, a Global Warming Potential (GWP) has been
calculated to reflect how long it remains in the atmosphere, on average,
and how strongly it absorbs energy. Gases with a higher GWP absorb more
energy, per pound, than gases with a lower GWP, and thus contribute
more to warming Earth.
The Greenhouse Effect
Sunlight passes through the atmosphere. When it strikes surfaces or gases that
can absorb it, heat is emitted. You can feel the effect directly by holding your
hand over dark asphalt or your car’s hood on a warm, sunny day. The surface
feels hot. It is re-emitting the energy it received from the sun.
Greenhouse gases in the atmosphere behave in a similar way. They absorb heat
energy rising from the Earth’s surface and re-emit some of that heat back down
towards the ground. The effect is similar to how an actual greenhouse works,
thus the name. Greenhouse gases act like the windows of a greenhouse, allowing
light through but trapping heat inside.
Excessive Greenhouse Gases Lead to Warming
Greenhouse gases surround
the Earth like a blanket. As we
use burn more coal, natural
gas, and oil, the blanket
becomes excessively thick,
dense, and less likely to allow
heat to escape. Heat gets
trapped inside the blanket of
greenhouse gases and the
Earth becomes too warm.
Greenhouse gases like carbon
dioxide (CO2), nitrous oxide
(N2O), and methane (CH4),
trap heat in the atmosphere.
With higher-than-natural
concentrations, they lead to
unnatural warming.
B. Exercises for skill subjects/Analysis questions using HOTS for
content subjects
i. Exercise 1
Directions: Fill out the table below with the effects of human activities to the
level of greenhouse gases in the atmosphere.
How are humans affecting the levels of greenhouse gases?
Human activities have significantly raised the levels of many greenhouse gases
in the atmosphere. Carbon dioxide specifically is the gas that has greatly
increased due to human activities. Prior to the industrial revolution, the
greenhouse gases were balanced. Once the revolution occurred, there have been
more fossil fuels burned, deforestation & other human activities that lead to an
increase in the greenhouse effect.
CAUSE EFFECT
Burning fossil fuels
from factories
(oil, coal, natural gas)
Deforestation
(cutting down trees)
ii. Exercise 2
Directions: Answer the questions below.
1. What would be the effect on the climate if there were more concentration of
greenhouse gases in the atmosphere?
____________________________________________________________________________
____________________________________________________________________________
____________________________________________________________________________
____________________________________________________________________________
____________________________________________________________________________
2. What would be the effect on the climate if there were lesser concentration of
greenhouse gases in the atmosphere?
____________________________________________________________________________
____________________________________________________________________________
____________________________________________________________________________
____________________________________________________________________________
____________________________________________________________________________
3. What will be the effects of global warming on the planet?
____________________________________________________________________________
____________________________________________________________________________
____________________________________________________________________________
____________________________________________________________________________
____________________________________________________________________________
4. What would you do to try and stop global warming from increasing?
____________________________________________________________________________
____________________________________________________________________________
____________________________________________________________________________
____________________________________________________________________________
____________________________________________________________________________
C. Assessment/Application
Directions: Answer the questions asked in the table below.
What are the
greenhouse
gases?
What do
greenhouse ________________ the atmosphere by trapping _______________.
gases do?
What is the
The __________________ of the atmosphere because of
greenhouse
insulation by ____________________________.
effect?
How does Incoming ____________________ from the sun ______________
greenhouse the Earth and is _____________________ by the greenhouse
effect work? gases, warming and insulating the Earth like a “blanket.”
Is the
greenhouse ___________! Because it maintains
effect a good ________________________________________________________.
thing?
So why is the
greenhouse
________________ of the greenhouse effect is a bad thing.
effect
Since there are more greenhouse gases in the atmosphere,
considered a bad
more ________________ is trapped which makes the Earth
thing and is
______________. This is called ________________________.
linked to global
warming?
Prepared by: Verified by:
CARISSA MAE T. CAÑETE ROQUE L. BORINAGA
Teacher School Head
