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Investigation Question 3:
How much can air temperature change during a day?
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What To Do
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Setting the
Scene
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Using data from a local newspaper or almanac, show students several very
different temperature reports for your location all attributed to the
same date. Without telling the students you have done so, include a daily
high, daily low, record high, record low, noontime temperature and so
on, so that while all of the temperatures are truly for your location,
they are actually somewhat different in what they tell. Ask the students
how it can be that so many temperatures can be attributed to the same
place and on the same date. As the idea of the temperatures being for
different times (among other differences) emerges, introduce the investigation
question.
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Presenting the Investigation
Question |
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Introduce your students to the investigation question: "How much
can air temperature change during a day?"
Have your students discuss the question in pairs, then in groups, and then as a whole class. Record their answers on the flipchart.
Have your students brainstorm ideas about how this investigation question could be investigated.
- Design an experiment that could be used to test the investigation question.
- What materials would be needed?
- What would you have to do?
- What would be measured?
- How long would the experiment take?
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Assessing What Your Students Already Know |
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Your students will know that outside temperature can vary. They will
certainly know of seasonal differences and most will know that it's usually
warmer in the daytime and cooler at night. Many will know that it is usually
cooler in the morning and evenings. They may connect this idea with the
position of the Sun in the sky. What they may not know is the extent to
which temperature can rise and fall over a period of time in one day (i.e.
the typical daily temperature range). Ask you students to consider these
questions, first in pairs, then in groups and then as a whole class:
- Does the outside air temperature change during a day?
- When during the day is it the coolest outside?
- When during the day is it the warmest outside?
- Does the air temperature inside the school (or home) change during
a day?
- How could you find answers to these questions?
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Exploring the Concept
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- In the classroom, give each group its thermometer. Have your students
check it and read the temperature it is showing in both degrees Fahrenheit
and Centigrade.
- Ask each group to report their measurement. (This can be a reality
check for you: they should all be roughly the same. If not, then either
a thermometer is faulty or the group does not know how to read the measurement.)
- Now tell your students that they are going to do this again every
hour for the rest of the day. Tell them also that they will be measuring
the outside temperature every hour as well. Ask them what would be a
good way of recording these measurements. (Some may say to write
them up on the board, or onto a piece of paper. Accept all ideas - do
not say any method a student offers in ·incorrect.· Hopefully,
somebody will suggest using a chart or table. If this does not happen
steer your students toward that idea.)
- Work with your students to build a table that will fit the observational
task. If they come up with a workable chart or method accept it and
proceed. If not you can lead them toward the one shown below. (It
is important that students learn about tables and how they can be constructed.
Point out the features.)
- Help your students to see how the symbols "°C" and "°F"
can be used to simplify recording. (You do not necessarily need to
spend time trying to explain what a ·degree· means in
this context - that can come later.)
- Now ask your students to think about today's weather. You can use
questions like this to promote discussion:
· Is it warmer or cooler outside right now than it was yesterday?
· Do you think it will remain the same all day - get warmer/cooler?
· Will it be different in different places - sunny place, shaded
place?
· What about inside the building - will the temperature vary
there?
- Have your student groups develop predictions based on what they already
know about daily weather. Encourage them to be as precise as they can
be with these. Here are some likely candidates for predictions:
· The outside air temperature will rise at first then begin to
fall.
· The outside air temperature will continue to rise.
· The outside air temperature will fall throughout the day.
· The outside air temperature will be different in different
places (sunny place, shady place.)
· The outside air will have a wider range of temperature than
the inside air over time.
· The inside air temperature will remain the same all day.
· The inside air temperature will be different in different places
(sunny window, shady cupboard.)
(You will need to decide just how wide you want this investigation
to be. You could have all students follow just one prediction. Everyone
can make the same observations and measurement with regard to the
same prediction. The advantage here is that it is easy to organize
and data can be pooled to check reliability - a common scientific
practice. On the other hand, you could broaden this out so that different
groups are observing and recording different aspects of air temperature.
For example, if each group records temperature in a different place
in the schoolyard, it is likely that their results will differ somewhat.
This is why, for example, the National Oceanic and Atmospheric Administration-NOAA-has
established standards for the siting of thermometers used for official
measurements-see the
NOAA website for details. Varying the sites at which measurements
are taken allows the class to cover a much wider range of factors
and allows different groups to specialize then share their findings
- another common scientific procedure. You decide!)
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Make sure that each student group writes down its prediction(s)
and the reasons for them. Tell them that they will look again at these
when they have made and recorded their observations.
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Find a way for students to test their predictions by taking their
temperature measurements on an hourly basis throughout the school
day. This may need some organizing ahead of time. Individual students
within the groups can take turns in doing this - slipping outside,
or within the building, to take and log a reading. (It might be
good to alert your administration and colleagues that this is going
to happen, just to avoid misunderstandings.)
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When all measurements have been taken, have each group revisit the
prediction(s) it made. The group can then judge whether the prediction(s)
is/are supported or not supported by the data. (Either way is important.
If a prediction is proved correct, it confirms the reasoning. Even
if a prediction is not supported, it is still useful - it helps to
rule out the reasoning so "we know that's not the explanation,
it must be something else." Help your students to see that all
results can be helpful in science.)
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