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Lesson History |
School |
Franklin Middle School (please give me feedback)
(please take a look at the big
picture)
Please note that this demonstration is currently being developed.
I do not yet know how much give the ice will have and how best
to demonstrate that give to the class. Further, I do not know
if I can pass them around or let groups have one or if I need
to do it as a demonstration up front with some sort of camera. |
Class |
8th Grade Science
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Date(s)
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est. March 2004
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Learning Objective |
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This demonstration
will get students thinking about how one can know the
state of matter inside (or under, depending on your
point of view (whole world vs. local)) the crust of
an astronomical body.
National Standard(s) |
PRIMARY STANDARD (more
here)
Sci.I.1 All students will ask questions that
help them learn about the world; design and conduct
investigations using appropriate methodology
and technology; learn from books and other sources
of information; communicate their findings using
appropriate technology; and reconstruct previously
learned knowledge.
Sci.V.1 All students will describe the
earth's surface; describe and explain how the
earth's features change over time; and analyze
effects of technology on the earth's surface
and resources.
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Driving Question |
- What is a crust?
- How are crusts related at different scales?
- What kind of energy does a crust contain?
- How is the crust of the Earth and other planetary
bodies related to the crusts of things we use
every day?
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as Related
to Objective |
- Students
will see a practical example of
a planetary crust.
- Students
will consider a crust on the small
scale of a balloon full of ice.
- Students
will see how strong a crust is
which is containing a liquid. This
may give some insight into the
violence of volcanic eruptions. (This
may not be as strongly related
to the driving questions as other
lessons are.)
- Ice
cubes which are not frozen solid
also display these crusts.
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Activity |
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Preparation |
- Buy
water balloons (15 minutes).
- Fill
water balloons (5 minutes).
- Allow
water balloons to almost freeze from the outside
in (several hours).
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Materials Needed |
Resource |
What is it? |
File(s) |
Water Balloons
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Fill water balloons with water and
leave them out in a snowbank to freeze. You will want
to pack snow all around them to make sure they freeze
evenly. Alternatively, you may want to turn them as
they are freezing.
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none
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Activity Time |
Depends on how in depth the
discussion goes, and what questions the students
have. I'm guessing one 50-minute class period,
but if it's shorter then we could move on to
the lesson on
the Science
News article the
same day and that would be good.
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Instructional Strategies
(Science Instruction pg. 244) |
This
is primarily a demonstration of the properties
of solid spheres with molten interiors. It is
introduced by a discussion of the Earth's crust
(including glaciers) and molten interior, and
is followed by a discussion of planetary crusts
and dead planets and leads to a recitation on
a Science News article. |
Instructional Sequence |
- (5-10 min) Discuss water (glaciation, how
water from the ocean snows over ice to form
glaciers which melt
back to the ocean, how this gouges out great
lakes) as part of the Earth's crust (tectonic
plates, Earth's crust, molten core, magma). During
every portion of the discussion, feedback will
be given to the students informally.
- (while talking) Take out the frozen water
balloon and start to unwrap it.
- (10-15 min) Talk about ice as rock and how
certain moons and all comets have a solid surface
of (dirty) water ice. This solid ball in my
hand could be solidifying rock (like Mars) or
ice (like Europa).
- (10-20 min) Ask the class how we might be
able to tell a completely solid planet from
a partially molten one.
The class will brainstorm and each member will
make a concept map of the brainstorm in their
notes. Perhaps a student or students
come up with the method used in the article
we read.
- (5 min) (I originally got the idea for this
lab from observing how ice cubes freeze from
the outside in. The problem is, that when I
try to get them out of the tray, they break.
I therefore decided using balloons to hold the
water might work better. I have not yet gotten
a working model for this and am waiting for
a snowfall to see how they freeze.)
At this point in the lesson, I want to show
the flexibility of ice balloon in some manner
to be determined. I need a good snowfall to
test this demonstration and see how best it
will work, but I have several ideas:
- Give them to the students: ideally, it
will be very easy to make an ice balloon
that deforms readily without breaking too
easily. If this is true, I can give every
group an ice balloon, maybe even with the
rubber removed, and they will easily see
the deformation for themselves.
- Pass one around: it may be that the ice
balloons are difficult to make properly,
so that it is impractical to make one for
each group. If they are strong enough, and
deform easily enough, I could pass one around.
If students break it, it could become a
teaching moment for how the Earth breaks
in volcanoes and earthquakes.
- Demonstrate up front: perhaps the balloons
will be particularly fragile, such that
I will not be able to pass them around (or
I can tell a particular class is too rowdy).
In this case they may be able to gather
round and watch as I deform it carefully.
- Use an aid: it could be that the deformation
is too small to measure (as water is an
"incompressible" liquid), and
that some aid (such as the overhead) would
be necessary to magnify the effect. Alternatively,
another liquid could be sought to fill the
balloons and we return to the first idea
for demonstration and try all the ideas
out again.
- (5-10 min) Hopefully there will be some give
in the actual sphere that the students can feel
(probably not though). Pass the sphere around.
As we continue the discussion, we will also
talk about the reasons why each method would
or would not work. (I have not yet done this.
I'm waiting for a good snow fall.)
- (transition) Lead into the
discussion on a molten Mars where they will
apply their knowledge. The article will
use compressing the planet as a means for measuring
the liquidity of Mars' interior, but any valid
methods will be accepted.
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Cautions |
Ice balloons will be hard and
students must be warned not to throw them.
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Assessment |
During discussion there will be informal assessment of prior
and post activity knowledge. I will be looking for prior
knowledge on the process of glaciation in particular and
on the water cycle in general as well as knowledge about
the structure of the Earth. (This is connected to knowledge
they gained before the lesson, and what they need to know
afterward. It depends on the final sequencing which has not
yet been determined.) Depending on where this lesson falls
in the sequence of the unit, this
will
either
be a
brief review for the students or it will be brief introduction.
I'm not looking for take home knowledge here, but if I can
stress these processes over and over, students should eventually
get it.
During the demonstration I am looking for questions and
comments which show critical thinking about how we could
tell the difference. (Is there give? Can you stick your finger
through (volcano)?)
(Everything gets so tied together. The real key assessment
for this lesson plan is actually embedded in the next one. The
students will apply what they have learned to inform their
understanding of the article showing that Mars has a molten
core based on this technique of observing the squeezing of
the crust.) (I'm more interested in them learning how
to think like a scientist than in the particular solution,
though it would be good for them to know that too.)
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Rationale |
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- Objective
-- It is worthwhile knowing how modern science can
decide that Mars still has a molten core. This demonstration
takes a modern marvel and makes it understandable
on an everyday level.
This shows science in the real world as it is practiced.
- Sequence
-- The sequence is set up to engage students starting
with their previous knowledge and leading them through
a discussion to make the article that follows seem
interesting to them.
- Assessment
-- Informal assessment makes sense in this lesson
as I am just starting to get students to think about
these issues. The real assessment comes in the next
lesson when they show they understood the concepts
here by understanding the Science News article.
- Parts & Whole
-- A discussion without demonstration can be boring.
A demonstration without discussion is amusing, but
without lasting understanding. A discussion with
demonstration can leave a lasting construct in a
child's mind which they can keep and use in the future
to understand new phenomena.
- Technique
-- This lesson is an example of scaffolding the scientific
approach to thinking about problems as I am giving
my students a way to understand the article
which follows.
How it Went/Lessons
Learned |
I haven't tried this lesson in the classroom yet. The
refrigerator in my dorm doesn’t cool things evenly
enough to do this.
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