Big Things Come in Little Packages

Transcription

Big Things Come in Little
Packages
Learning Objectives: Objects that are the same volume but
different weights have different densities.
GRADE LEVEL
K–5
SCIENCE TOPICS
Physical Properties
Techniques
PROCESS SKILLS
Comparing and
Contrasting
Measuring
Organizing Data
Evaluating
GROUP SIZE
1–2
SNEAK PEAK inside …
ACTIVITY
Students learn about density by comparing
gift-wrapped packages that are the same
size but have different densities.
STUDENT SUPPLIES
small boxes, all same size
coins, nails, screws, bolts, or other heavy
metal scraps
wood blocks or scraps
foam rubber, Styrofoam peanuts, or large
marshmallows
gift wrapping paper
ADVANCE PREPARATION
Fill boxes with different materials and wrap.
OPTIONAL EXTRAS
EXTENSIONS
Twenty Questions (p. A - 6)
Determining Volume (p. A - 6)
Determining Density (p. A - 7)
Advance
Preparation
TIME
REQUIRED
15 minutes
Grades K–5
Set Up
Activity
Clean Up
0 minutes
20 minutes
2 minutes
A-1
Chemistry in the K–8 Classroom
2007, OMSI
SUPPLIES
Item
Amount Needed
small boxes of the same size (approx. 4-inch cubes)
3 per class
coins, nails, screws, bolts, or other heavy metal scraps
enough to fill box
wooden block or scraps of wood
enough to fill box
foam rubber, Styrofoam peanuts, or large marshmallows
enough to fill box
gift wrapping paper and tape
enough to cover each
box
For Extension or Demonstration supplies, see the corresponding section.
ADVANCE PREPARATION
Supplies Preparation
Boxes:

Make sure that all three boxes are the same size and shape.
(A cut-down half-gallon milk carton works well as a box.)
Fill one box as full as possible with heavy metal scraps, nuts,
bolts, screws, etc.
Fill a second box as full as possible with a block of wood or
scraps of wood.
Fill the third box (without making the box bulge) with foam
rubber, Styrofoam peanuts, or large marshmallows.
Gift wrap the three boxes. You can wrap the three boxes
identically or wrap them differently so that the students will
have an additional criterion for comparing the three boxes.
SETUP

none
Grades K–5
A-2
2007, OMSI
INTRODUCING THE ACTIVITY
Let the students
speculate before
offering answers to
any questions. The
answers at right are
provided for the
teacher.
Choose questions
that are
appropriate for
your classroom.
In this acitivity, students will have the opportunity to compare giftwrapped packages that are the same size but different densities.
Have the class look at (but not touch!) the three gift-wrapped
boxes. By not allowing the students to touch or feel the boxes, you
will limit the information they can gather and also increase their
curiosity.
Atoms and molecules are also impossible to touch and feel
directly, yet scientists are still curious about them. Scientists use the
properties of materials to learn about the atoms and molecules
inside them.
What is alike about the packages?
They are the same size or volume, they take up the same amount
of space, they are all boxes, and they are all wrapped as gifts.
What might be different about the packages?
They could be different weights, different values, filled to a different
degree, etc. It’s hard to tell by just looking.
Without having the students lift or touch the boxes, ask:
Which box do you think is heaviest?
You can make a bar graph of student responses:
Column one
= number of students who think box 1 is heaviest.
Column two
= number of students who think box 2 is heaviest.
Column three = number of students who think box 3 is heaviest.
Column four
= number of students who think all boxes weigh the same.
Have the students hypothesize what is in the packages. This will not
be a very informed hypothesis because they have very little
information. The only clue they have is package size.
Grades K–5
A-3
2007, OMSI
CLASSROOM ACTIVITY
This activity does not have a Scientific Procedure. Instead, lead the activity according to
the directions below.
NOTES
One of the best ways to find out what’s inside the box is to
measure as many things as possible about the box, such as the
weight, size, shape, color, etc.
Here is a fun way to demonstrate the different weights of the
boxes to the class.
1. Have three volunteers come forward (preferably including
one very small student and one very large and apparently
strong student).
2. Give the lightest weight package (the foam or
marshmallows) to the smallest volunteer. Give the heaviest
package (metal) to a strong volunteer.
3. Ask the three students to do arm lifts with their package. If
the packages are on the small side, the students may
need to extend their arms to experience the weight
difference as they do arm lifts.
4. Ask the class to count the number of arm lifts each student
can do with the package over a period of time (about 1
minute). Compare the number of arm lifts for each
package.
5. Ask the volunteers how difficult the task was. Compare
their answers.
6. Ask the class: What might be different about the
packages? Which box is heaviest? (You can make another
bar graph of student responses.) Ask the class: Who
changed their minds about which package is heaviest?
On what did you base your decision?
7. If it is still not clear which package is heaviest, give several
(or all) students the opportunity to lift each of the
packages and compare.
8. Have students hypothesize again what is in the various
packages. They have more information, or data, now.
When scientists make a hypothesis, they base it on all the
information they have.
9. Now have three volunteers unwrap the package and
inspect the contents. They can show the class, or play “20
questions” with the class, allowing the class to gather more
information by asking questions.
Grades K–5
A-4
2007, OMSI
CLASSROOM DISCUSSION
Ask for student
observations and
explanations. Let
the students guide
the discussion and
present their
hypotheses before
discussing
explanations.
Choose questions
that are
appropriate for your
classroom.
Scientists use density to describe how heavy something is
compared to its size. Objects that are the same size but different
weights have different densities.
Which box is heaviest: the one with metal, foam, or wood?
metal
Which is lightest?
foam
Density is mass (similar to weight) divided by volume (size). When
two things are the same size, the heavier one is more dense.
Which box is least dense?
foam
Can you think of some very dense objects?
metal objects, rocks, etc.
Can you think of some objects that are not very dense?
balloons, marshmallows, pillows, an empty box, etc.
EXPLANATION
Scientists study objects by learning about their properties. Color, size, and shape
are all properties that allow scientists to study what objects look like. In this
activity, students learn that even when things look alike, there are still other
properties that allow them to tell objects apart.
The Matter Around Us
All matter is made of atoms. Atoms combine to make molecules. Atoms and
molecules are too small to see, but, together, they make up all stubstances. To
find out how much matter is in a substance, scientists weigh the substance to
find its mass. The more matter an object has, the more mass it has.
Density
In this activity, students study three objects that all have the same volume, that is
they each take up the same amount of space. The three boxes all look the
same, but students find out that they all have a different amount of mass; they
each weigh a different amount. When scientists compare an object’s mass to its
volume, they call this property the density of the object.
Grades K–5
A-5
2007, OMSI
The lightweight package contained foam, Styrofoam, or marshmallows. In these
substances, the atoms and molecules are not packed together very tightly.
There is not very much matter packed into the space. For this reason, the
package has the least mass and is the least dense.
The metal-filled box was the most dense because the atoms in metals tend to be
packed very tightly. Each particular type of metal has its own density; for
example, lead is much denser than aluminum. The atoms in lead are larger and
more tightly packed than the atoms in aluminum.
Sink or Float?
The concept of density explains why things sink or float in water. If a solid (like
wood) is less dense than water, it will float on the water—regardless of its weight.
For instance, pianos float on water, even though they are very heavy, because
they are made of wood, which is less dense than water. On the other hand,
solids that are more dense (like metals) will sink in water. Even a piece of metal
as light as a dime will sink in water, because the metal is more dense.
For more examples and discussion about density, see the Explanation section in
the activity Density Rainbow.
EXTENSIONS
Extension A: Twenty Questions
Have the students bring in gift-wrapped boxes. Let other students hypothesize
what is in them. Let other students lift the packages. They can play 20 questions
with each owner.
Extension B: Determine Volume (Grades 3–5)
Students determine the volume of the three boxes.
Extra Supplies
ruler ( inch or centimeter)
Extra Instructions
Measure the width, length, and height of the boxes. (Be sure to use the
same units for each measurement.)
Determine the volume by using the following equation:
volume = width x length x height

If students measured the dimensions in inches, then the volume is measured
in cubic inches. If students measured the dimensions in centimeters, then
the volume is measured in cubic centimeters.
Grades K–5
A-6
2007, OMSI
Extension C: Determining Density (Grades 4–5)
Students determine the density of each box.
Extra Supplies
rulers (inch or centimeter)
scale (ounces or grams)
Extra Instructions
Find the mass of each box.
Determine the volume of each box (See Extension B above). If your scale is
in ounces, it is best to measure in inches. If your scale is in grams, it is best to
measure in centimeters.
Determine the density using the following equation:
density =

mass
volume
The result should be in either pounds per cubic inch or grams per cubic
centimeter.
CROSS-CURRICULAR CONNECTIONS
FORENSIC
SCIENCE
MATHEMATICS
Counterfeit Coins and Jewelry
Research how law enforcement can use density to detect counterfeit
coins and jewelry.
Density of Other Objects
Extensions B and C require multiplication and division, respectively. You
can further develop this by having students measure and weigh other
objects to determine their volumes and densities.
LANGUAGE ARTS
Mystery Object
Have the students write a story about a mystery package. Have them
reveal clues using descriptive language.
ECOLOGY
Density of Ice versus Water
Ice is less dense than water, which is why it floats. Write about how the
world would be different if solid water was more dense than liquid water.
(Oceans and lakes freezing from the bottom up, etc.)
Grades K–5
A-7
2007, OMSI
RESOURCES
Great Explorations in Math and Science (GEMS), Discovering Density, Lawrence
Hall of Science
Target level: 6th to 10th grade
This teachers’ manual includes five 25- to 50-minute lessons and possible follow-up
lessons. Each activity is well designed, includes detailed instructions, handouts, and data
tables.
VOCABULARY
atoms:
a very, very small particle that makes up all matter
density:
describes how tightly packed matter (molecules, people) is
in a space; dense is the adjective, density is the noun
mass:
the amount of matter in an object or substance; measured
by weight
matter:
anything that has mass and occupies space; stuff
molecule:
a group of at least two atoms held together in a definite
arrangement
volume:
the amount of space filled by an object or substance
Grades K–5
A-8
2007, OMSI
SUPPLY WORKSHEET
This worksheet is available online at www.omsi.edu/k8chemistry.
Recommended group size: whole class
Number of Students:
Supplies
small boxes of the same size
(approx. 4-inch cubes)
coins, nails, screws, bolts, or other
heavy metal scraps
wooden block or scraps of wood
foam rubber, Styrofoam peanuts, or
large marshmallows
gift wrapping paper and tape
Number of Groups:
Amount Needed
Supplies
on Hand
Supplies
Needed
3 per class
enough to fill box
enough to fill box
enough to fill box
enough to cover each box
Extension A
No additional materials needed
Extension B
rulers
1 per group
Extension C
rulers
1 per group
scale
1 or more for class to share
Grades K–5
A-9
2007, OMSI
Grades K–5
A - 10
2007, OMSI