Blankets the Earth
Does it Affect Bulbs?
a cold blanket of snow affect Journey North Tulip Gardens? As tough
as tulip bulbs are, they contain some tender plant parts. Is snow cover
likely to freeze and damage them . . . or does it play another role?
YOU solve the mystery! Look for clues in these experiments done by
Journey North students.
at what students in Alaska found:
They dug a deep cube-shaped pit in the snow. Next, they stuck four thermometers
into the snow about four inches apart. Each one was deeper than the next.
Here's what they found:
degrees F (-13 degrees C)
degrees F (-11 degrees C)
degrees F (-9 degrees C)
degrees F (-4 degrees C)
at what another group of Journey North students discovered one
winter. They tested temperatures above and below the snow
for two weeks in February. (Click
on each graph to enlarge it.)
above the snow
below the snow
and Discussion Questions
the graph from the first group of students:
does the data tell you about snow depth and temperatures? Was it
warmer or colder the further down they went?
was the temperature difference from 0 to 12 centimeters down? From
0 to 40 centimeters down?
the graph from the second group of students:
do these graphs tell you about temperatures below the snow?
is the high and low temperature on each graph? What is the temperature
range (highest minus lowest)?
the temperatures vary more above or below the snow?
conclusion: Do you think that deep snow is more likely to
damage or protect your bulbs? Explain your thinking.
The soil gives off some heat. Fresh, uncompacted snow has 90 to 95 percent
air trapped between its crystals. Because the air can barely move, it
can't easily transfer heat away from the soil or cold down into the soil.
The deeper the snow, the more it insulates the ground — and the
plant parts beneath it. The temperature below fresh snow increases by
about 2 degrees F for each inch of accumulation.