How
to make and read a graph
It's easy to make a Datapult
sm graph
showing how much power the solar
panels are producing and how
much energy the school is using.
Just point and click on the buttons
and drop down lists to select
the time frame and energy information
you want on the graph. Then click "Make
Graph."
Want to know more about the
data on the graph? Move your
cursor over any of the diamonds
on the graph, and specific
data for that point will appear
in the bar at the bottom of
your browser screen. If your
graph looks at more than one
day, click on a diamond and
Datapultsm will
create a graph for the day
you picked. To change your
graph or create a new one,
just click on the "Dates" tab
at the top of the page and
you'll be able to change one
or more selections and make
a new graph.
What the Lines on the Graphs
Show
The solar panel graph shows the amount of electricity flowing from the panels
into the power circuits of the school, but it's impossible to know that the electrons
from the panels went just into the refrigerators, or the lights or the computers.
When the sun is out and everything is perfect, the graph will show peak electricity
of 2.0 kilowatts (kW) which is the same as 2,000 watts. That amount of electricity
will light 20 100-watt light bulbs. You might notice that the graph line sometimes
goes below the zero line. How can that be if the panels make electrons and don't
use them? It's because of the way the panels work and electrons move in circuits.
It takes a certain amount of sunlight to excite the elections in the panels enough
to flow into the school like water from a fire hose. If they aren't excited enough
and are flowing only like water from your garden hose at home, and the electrons
inside the school are flowing around the circuits like the high-pressure water
in a fire hose, some of the inside school electrons will push out into the solar
panels. Datapultsm records that electron flow as a negative number
and graphs it that way.
Under ideal conditions, the
panels can produce 2 kW
of electricity. BUT, what happens
if snow isn't brushed off
the
panels? Or dust isn't washed
off once in a while with
a hose? Or the trees nearby
grow
and start to shade them?
Your panels won't give as much
electricity
as they can unless you
take care of them.
Day Light Graph
The day light graph shows how much electricity is being used by lights on two
of four lighting circuits. These circuits run the lights mostly on the west
side of the school. These lights use about 38 percent of the electricity
used by all the lights in the school for daytime activities.
Night Light Graph
The night light graph records electricity used by indoor and outdoor lights
after you go home. These lights include parking lot lights, which come on
and off automatically using photocells similar to the solar panels. They
sense when there is enough light for you to see in the parking lot and turn
off the lights in the morning. The photocells can determine when it's dark
outside and turn the lights on at night.
Total School Graph
The total school graph shows all the electricity the school uses for computers,
the lights, fans to move air around to keep the school warm or cool, and
anything else that runs on electricity. We'd like to hear about how your
school uses solar energy, too. If you have questions or comments about our
site, drop us a line Soon, we'll have more schools on this web site so you
can compare how different schools generate and use electricity.
