Understanding Insulation and Energy Saving in Grade 7 Natural Sciences

 
Natural Sciences
Grade 7
 
Term 3: Energy and Change
Insulation and energy saving
 
Topic 4
Insulation and energy saving
 
Heat loss and gain
 
Natural Sciences - Grade 7
 
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Heat energy is 
lost
 to the environment by 
conduction, convection and
radiation
.
The 
human body 
loses heat through radiation.
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Food
 cooked over a fire loses heat by convection.
Warm beverages 
lose heat through conduction through the cup it is in as
well as through convection above the surface of the liquid [e.g. coffee; milo;
tea; etc.].
Insulators such as 
a geyser blanket 
can be used to restrict heat loss.
 Picture [a rooftop hot water geyser].
 
Natural Sciences - Grade 7
 
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Solar geysers 
absorb heat from
the sun through radiation.
 
Convection currents 
from a
heater warm up the air in a room.
 
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Natural Sciences - Grade 7
 
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Solar energy 
comes from the sun.
The 
water 
in our homes can be 
heated
 directly
through 
solar energy.
The 
heat of the sun 
heats the solar water
heaters.
 
Natural Sciences - Grade 7
 
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The 
cold water flows 
through the solar
heater’s pipes.
The water in the solar heater’s black pipes on
the roof is 
heated by the Sun. 
[Picture: How
a roof top hot water geyser works].
It is important that the 
heater faces 
the
direction that gets the 
most Sun 
during the
day [Face south –homes in northern
hemisphere; face north – homes in southern
hemisphere.
The heated water flows into the 
hot cylinder
.
The hot cylinder is 
connected
 to the 
house’s
water pipes.
 
Natural Sciences - Grade 7
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Exploring heat loss, gain, and insulation techniques in the context of energy conservation. Topics include solar water heaters, conduction, convection, and radiation as mechanisms for heat transfer.


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  1. Natural Sciences Grade 7 Term 3: Energy and Change Insulation and energy saving

  2. Topic 4 Insulation and energy saving Heat loss and gain Natural Sciences - Grade 7

  3. Heat loss and gain Heat loss and gain Heat energy is lost to the environment by conduction, convection and radiation. The human body loses heat through radiation. A geyser can lose heat through conduction through the casing of the geyser and through convection through the air surrounding the geyser. Food cooked over a fire loses heat by convection. Warm beverages lose heat through conduction through the cup it is in as well as through convection above the surface of the liquid [e.g. coffee; milo; tea; etc.]. Insulators such as a geyser blanket can be used to restrict heat loss. Picture [a rooftop hot water geyser]. Natural Sciences - Grade 7

  4. Heat energy can also be gained or absorbed from the Heat energy can also be gained or absorbed from the environment environment Solar geysers absorb heat from the sun through radiation. Convection currents from a heater warm up the air in a room. The food in a pot on a gas / electric stove gains heat through conduction. Natural Sciences - Grade 7

  5. Solar water heaters Solar water heaters Solar energy comes from the sun. The water in our homes can be heated directly through solar energy. The heat of the sun heats the solar water heaters. Natural Sciences - Grade 7

  6. A solar water heater works as follows: A solar water heater works as follows: The cold water flows through the solar heater s pipes. The water in the solar heater s black pipes on the roof is heated by the Sun. [Picture: How a roof top hot water geyser works]. It is important that the heater faces the direction that gets the most Sun during the day [Face south homes in northern hemisphere; face north homes in southern hemisphere. The heated water flows into the hot cylinder. The hot cylinder is connected to the house s water pipes. Natural Sciences - Grade 7

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