Transcript Engineers, what is wrong here?

Engineers, what is wrong
here?
There are penguins all over the world, not
just in Antarctica.
The red dots indicate where penguins live.
There are penguins all over the southern hemisphere.
Even in South Africa…
Boulders Beach is on the coast of
South Africa.
Here, the Boulders Beach penguins live. As the climate across the globe
changes, these penguins are getting hot. To keep from overheating, they
cool off in the water. But this survival technique has not worked in
their favor…
Boulders Beach Penguins
So the park rangers have built the
penguins little houses to protect
their eggs AND to help keep
them cooler.
The sea gulls are stealing their eggs!
This is helping them survive!
Climate change is causing penguins in Antarctica to
become endangered by eliminating available
habitats
How bad is climate change?
Are we to blame?
But how can we help?
What can we
do at home to
help the
penguins?
For starters,
we can
conserve
energy so we
don’t use as
many fossil
fuels in power
plants! But
that will take
some time!
How can we
help them
now?
Challenge: Can you
design a
dwelling that will
protect your
penguin from
increasingly
warmer
temperatures?
Review of Thermal Energy Transfer
• Conduct the following experiments to gain a
better understanding of thermal energy
transfer, insulators, and conductors.
Insulation and Conduction
Soda Cans
• You are leaving on a field trip and you want to
keep your soda cold, but ice packs are not
allowed. What can you wrap the can in to
keep it cool?
Materials
• Predict which material you think will keep the
soda can colder longer?
– A wool sock, paper towel, aluminum foil, plastic
wrap, cotton sock, nothing
• Starting temperature of can 42 degrees F
Insulators and Conductors- Soda Cans
• Which material appears to work the best?
– Wool
• Which material appears to work the least?
– Cotton sock
• When you wrap a can of soda, what are you really
trying to do?
– Keep the heat out, not keep the cold in
• From the data collected, how would you rate
aluminum foil? Why?
– Not very good, it is a metal and good conductor
• What is the best fabric to wear in the winter to
keep you warm?
– wool, because it traps air and doesn’t absorb moisture
Metal vs. Other Materials
• Preview: Which tray is colder?
• Watch the video, why don’t the ice cubes melt
at the same rate? https://www.youtube.com/watch?v=rrYAmEptMLQ
Battle of the Spoons
• Predict: Which spoon (silver or plastic) will
keep an ice cube from melting faster?
• Which spoon is causing the ice cube to melt
faster? Why?
– Metal, It is conducting heat from my hand through the
spoon and melting the ice cube.
• Why didn’t the other spoon melt the ice cube as
fast?
– The plastic spoon does not transfer heat well
• Which spoon is a conductor?
– Metal
• Which spoon is an insulator?
– Plastic
Draw
Metal Spoon
Heat is conducted
from my hand, along
the metal, which is a
conductor, to the ice
cube, which melts
Plastic Spoon
Heat is NOT
conducted from my
hand, since plastic is
an insulator. The ice
cube does not melt
Tray temperatures
• What are the actual temperatures?
• So why does the metal feel colder?
– It conducts heat away from your hand quickly
Explain the melting ice blocks
• The blocks are made of different materials.
The fast melting cube was on a good
conductor (metal). The slow melting cube was
on a good insulator (wood, plastic).
Hot House
• How can conduction, convection, and
radiation all come from a single source?
Data Collection
• What method of HEAT TRANSFER is heating up the
attic?
– Conduction- The attic gets hot because the hot roof (esp
the black roof) is absorbing the light and it transfers its
energy directly to the attic
• What method of HEAT TRANSFER is used when we
FLIPPED the house?
– Convection- the cold, dense air will sink and the warm
air will rise
• What method of HEAT TRANSFER is blocked when
we covered the house with the space blanket?
– Radiation- the heat instead of being absorbed is
reflected away
Brainstorm
• Using your knowledge of insulators,
conductors, conduction, convection, and
radiation, design a dwelling for your penguin
which will prevent it from melting under the
sun.
Materials
• What type of materials will you use?
– Cotton, wood, construction paper, foam, felt,
plastic wrap, aluminum foil
Design
• What will your design be? Remember your
penguin has to be able to get into and out of
your dwelling.
Are you designing a home for winter
heat losses?
What do
you think
the arrows
represent?
Where is
the heat
going?
Or for summer heat losses?
In the
summer, it’s
HOT! Heat
transfers
into our
houses!
Now
where is
the heat
going?
We need to slow down heat transfer.
In other words, we need to stop the
from happening!
Test Oven
•Radiation from
heat lamp above
•Conduction and
convection from
black floor
•Convection and
radiation from 4
shiny foil walls
Conserving energy is the key to help…