BSCS Science:
An Inquiry Approach
Level 3
First edition, © 2010 by BSCS
Unit 5 Overview
5415 Mark Dabling Blvd. | Colorado Springs, CO 80919 | 719.531.5550 | www.bscs.org
TE_NT_Ch01_002-073.indd Page 3 6/11/09 7:51:03 PM user
/Volumes/103/KHUS025/work%0/indd%0/Nano-Technology/Chapter 1
Unit Overview
Goals for the Unit
Nanoscience and nanotechnology are part of a relatively
new field of science. More and more, we are hearing about
new nanotechnology applications in the news, but often
there is little information about the science involved. In
fact, nanoscience is multidisciplinary, drawing from fields
such as physics, chemistry, materials science, biology, and
engineering. It draws from the principles of these varied
fields to allow scientists to manipulate, control, and measure
properties of materials at the nanoscale. This work then leads
to nanotechnology discoveries, which results in these materials
being used in new devices and applications.
In this unit, BSCS Science: An Inquiry Approach—
Understanding the Science of Nanotechnology students will
learn about the scientific principles that form the foundation
on which nanotechnologies are developed. Chapter 1,
Self-Assembly, focuses on physical science principles that are
important to self-assembly, a key idea in building nanoscale
materials. Chapter 2, Using Nanoscience, has a biology
focus, with students examining naturally occurring nanoscale
systems as well as some of the ethical questions that surround
nanoscience. Students are introduced to some applications
in nanotechnology, but it is important to remember that
the unit focuses on developing students’ understanding of
some of the most important principles of the science behind
nanotechnology. This understanding will give them a good
foundation to apply these science principles to any situation.
By the end of this unit, students should understand the
following:
• Properties of matter can vary depending on the size and
the shape of the particles making up the material.
• Under certain conditions, atoms and molecules assemble
themselves into organized structures.
• Electromagnetic attraction is the fundamental force
that holds molecules together. The strength of the
force depends on the nature and the arrangement of the
particles involved.
• The structure of matter (for example, the shapes of
molecules) is directly related to function (for example,
how molecules may join together), as can be seen at the
nanoscale level.
• Models and the use of technology are a good way to gain
an understanding of processes at the nanoscale level. And
while models have strengths, they also have limitations.
• Although nanotechnology has a variety of potential
applications, there are risks that must be considered.
All the units in Level 3 of BSCS Science: An Inquiry
Approach reinforce specific, overarching themes. The themes
are energy flow and energy transformations, and the use of
models, evidence, and explanations. In Understanding the
Science of Nanotechnology, students will investigate these
concepts in two chapters.
Understanding the Science of Nanotechnology
3
TE_NT_Ch01_002-073.indd Page 7 6/11/09 7:51:17 PM user
/Volumes/103/KHUS025/work%0/indd%0/Nano-Technology/Chapter 1
Strategies for the
Unit Engage
How Small Is Nano, Anyway?
Activity Overview
The goal of this unit Engage, How Small Is Nano, Anyway?,
is to help students develop a conceptual reference point for
the size of small objects, including nano-sized objects.
Understanding the relative scales of objects that are too small
to see will provide students with an important foundation for
the rest of the unit. Students will learn in chapter 1 that the size
and the shape of particles play a role in whether or not particles
aggregate. Therefore, it is crucial that students have some idea
of how big nanoparticles are in comparison with other small
objects.
Before You Teach
Background Information
As a prefix, “nano-” indicates any quantity times 10⫺9.
For example, 3 nanometers (nm) is 3 ⫻ 10⫺9 meters (m). It
is difficult for anyone to conceptualize how big or small a
nanometer is. A proton is much smaller than a nanometer, and
a cell is much larger. In this activity, students will compare
large objects on a logarithmic scale with small objects on
another logarithmic scale. This means that each factor-of-10
mark on the scale represents objects that are 10 times larger
than objects at the previous mark. For example, an object
on the 105 mark is 10 times larger than an object on the 104
mark, 100 times larger than an object on the 103 mark, and
1,000 times larger than an object on the 102 mark. You may be
familiar with the pH scale. The pH scale is another example
of a logarithmic scale. A pH of 9 is 10 times more basic than a
pH of 8, and 100 times more basic than a pH of 7. The Richter
scale for earthquakes is also logarithmic. An earthquake that
measures 7 on the Richter scale has 100 times more shaking
amplitude than one that measures 5 on the Richter scale.
Materials
For each student
1 copy of copymaster 1.1, Large- and Small-Object
Size Lines
/,
For each team of 3 students
1 set of large-object cards from copymaster 1.2, Large-Object
Cards
1 set of small-object cards from copymaster 1.3, Small-Object
Cards (copied onto a different-colored paper from
the large-object cards)
Powers of 10 simulation link on the SR Web site
(optional)
Educational Technologies
After students do the unit Engage activity, you
may wish to have them work through the Powers
of 10 activity.
As You Teach
Outcomes and Indicators of Success
By the end of this activity, students should
1. be able to conceptualize the differences in size between
objects that are too small to see.
They will demonstrate their understanding by
• ranking objects from smallest to largest and
• placing objects on size lines.
2. make comparisons between the size differences of
objects they can see with the size differences of objects
they can’t see.
They will demonstrate their understanding by
• comparing objects on two size lines (one for large objects,
one for small objects) that are evenly scaled by factors of
10 and
• answering questions that ask them to make analogies
between size differences for large objects and size
differences for small objects.
Strategies
Getting Started
Start by asking students to think about the term
“nanoparticle.” Ask them to work as a class to come up with
objects that might be the same size as nanoparticles. If they
struggle, prompt them by asking, “Do you think nanoparticles are big or small?” “Do you think people can see
nanoparticles?” and “What are some other particles that are
too small to see?” Tell students that in preparation for the unit
on nanoscience, they will be thinking about the relative sizes
of objects in this activity so that they can have a better idea of
how large nanoparticles are.
Reminder of Possible Misconceptions
Students may not have previously had the opportunity to
compare the sizes of objects that are too small to see. They
may harbor several misconceptions, including the following:
• Atoms are not in cells.
All matter, including cells, is made of atoms. Atoms are not
drawn on diagrams of cells because they are extremely small
compared with the cell.
Advance Preparation
Make enough copies of copymaster 1.1,
Large- and Small-Object Size Lines, so that each
student will have his or her own copy. Make enough
copies of copymasters 1.2 and 1.3, Large-Object Cards and
Small-Object Cards, so that each team will have 1 set of each.
Make each set (large and small) on a different color of paper
so students don’t get them mixed up. Cut out the cards and
place them into sets. You may wish to laminate the cards so
that they can be used from class to class and year to year.
Students will work in teams of 3 for part of this activity.
Select teams of students ahead of time.
/,
• The nucleus of an atom is the same as the nucleus of a cell.
Understanding the Science of Nanotechnology
7
TE_NT_Ch01_002-073.indd Page 8 6/11/09 7:51:19 PM user
The nucleus of an atom is extremely
dense. It is made of protons and
neutrons and has a net positive charge.
The nucleus of a cell is extremely large
compared with the nucleus of an atom.
It is an organelle of a cell, containing
DNA and other important molecules
for cell function. Atoms make up
molecules, which in turn are used to
make the parts of cells (including the
cell nucleus). The word “nucleus” has
two very different meanings.
• Cells and atoms are about the
same size.
Students tend to study cells and atoms
in separate classes and never think
about their relative sizes. Cells are
huge compared with atoms: they are
approximately 10 billion times larger.
Cells are large enough to see with an
ordinary light microscope. Atoms are
difficult to “see” and require highpowered transmission electron microscopes or atomic force microscopes to
get an image.
• Numbers on a logarithmic scale go
up the same way that numbers on an
ordinary number line go up.
A logarithmic scale is one in which
every mark is 10 times larger than the
one before. An ordinary number line
goes up by even amounts. So while a
log scale might have the numbers 10,
100, 1,000, and 10,000, an ordinary
number line would go up as 10, 20,
30, 40.
Process and Procedure
In Steps 1–2, students should lay the
large-object cards out in front of them
on the table so that the whole team can
better see what the team is discussing.
They may simply rearrange cards
while discussing the best size order. As
students arrange the order of the large
objects, move around the room to get
a sense of their prior understanding. If
students disagree, encourage them to
present evidence to their team for the
order they think is correct.
Don’t hand out copymaster 1.1,
Large- and Small-Object Size Lines,
until students have completed Step 10.
Students may become confused, trying to
figure out the exact numerical sizes for
objects. It is not necessary for students
to know exact sizes; instead, students
should think about how each object
compares in size with the others.
8
Understanding the Science of Nanotechnology
/Volumes/103/KHUS025/work%0/indd%0/Nano-Technology/Chapter 1
In Step 4, encourage students to use
their own experiences when they explain
why they ordered things the way they
did. Students may have some difficulty
with objects they have never seen. For
example, it is unlikely that students have
ever seen Salto Angel Falls (the largest
waterfall in the world, with a clear drop
of 807 m, located in Venezuela), but it is
likely that they have seen waterfalls (or
pictures of waterfalls). When they have
difficulty with a specific object, ask them
to think about the size of a similar object.
In Step 6, allow students time to
remind themselves what each small
object is. They may need a moment
to remember what a cell nucleus is
compared with the nucleus of an atom.
Students will then sketch each object in
Step 7 so that they have a representation
to go with the words. Remind students
that the diagrams should be very simple
sketches, used to help them order the
objects and remember what each is.
If students get stuck in Steps 8–9, ask
them probing questions. For example,
if they don’t know how to rank protons
against cells, remind them that DNA is
in a cell, and DNA is a macromolecule
(a giant molecule). Then ask them,
“What are molecules made of?”
Answers to Steps 2 and 8,
SE pages 8–9
2. The correct order is listed here for
your reference. Students may not have
the order exactly right and should not
be graded on correctness at this point:
• Length of a sperm cell
• Width of a human hair
• Diameter of an egg cell
SE_NT_Ch01_002-073.indd Page 8 5/14/09 4:15:17 PM u-s081
/Volumes/103/KHUS024/indd%0/Nano-Technology/Chapter 1
UNIT ENGAGE
How Small Is Nano, Anyway?
Matter comes in all shapes and sizes, from the smallest subatomic particles
to the largest clusters of galaxies. We begin to understand the scales of
objects when we are young. For example, we learn that a key is much
smaller than a building. But when it comes to objects we cannot directly
experience, understanding their scale becomes much more difficult.
It can be difficult to think of how the size of something small compares
with the size of something big. For example, how big is the width of DNA
compared with the width of a human hair? If you read that a sheet of paper
is 100,000 nm thick, would you be able to picture what 1 nm is?
Not only is it difficult to think about how small objects compare with
large ones, but it is also difficult to imagine how small things might
compare with one another. You might have learned that atoms make up all
matter. You might also know that cells are matter. This means that atoms
must make up cells. But, when studying cells, did you ever stop to think
about where the atoms are? Many textbooks will show you the organelles
(mitochondria, Golgi apparatus, and so on), but they probably don’t list
atoms as parts of the cell. How does the size of an atom compare with the
size of a cell?
Understanding the Science of Nanotechnology focuses on the science of
objects in a specific size range: 10–100 nm. A nanometer is one-billionth
of a meter (or 1 ⫻ 10−9 m), but it is difficult to imagine just how small
that is.
Materials
For each student
1 Large- and Small-Object Size Lines handout
For each team of 3 students
1 set of large-object cards
1 set of small-object cards
Process and Procedure
To understand how the sizes of small objects compare, it is helpful to make
analogies between small objects and large objects. To help you make the
analogies, complete the following steps with your team.
1. Place the large-object cards face up on the table. Be sure that all team
members can easily see the cards.
2. Decide as a team the order for the large-object cards (put the smallest
on the left, the largest on the right). If you don’t know where to put an
object in the ranking, make your best guess.
Don’t worry about exactly how big each object is. Instead, simply rank the
objects from smallest to largest.
8 Understanding the Science of Nanotechnology
TE_NT_Ch01_002-073.indd Page 9 6/11/09 7:51:23 PM user
/Volumes/103/KHUS025/work%0/indd%0/Nano-Technology/Chapter 1
• Width of a dime
• Gold nanoparticle
• Height of a human being
• Cell nucleus
• Distance between bases in a
baseball diamond
• Length of a sperm cell
• Height of the Eiffel Tower
• Diameter of a human egg cell
• Height of Salto Angel Falls
• Width of a dime
• Height of Mount Everest
• Length of Trans-Canadian Highway
• Diameter of Earth
• Distance from Earth to the Moon
8. Once again, the correct order is listed
for your reference. Students should not
be graded on correctness at this point:
• Proton
• Nucleus of a gold atom
• Gold atom
• Sugar molecule
• Width of DNA
• Width of a human hair
In Step 11, hand out
copymaster 1.1, Large- and
Small-Object Size Lines.
/,
Students should write the
names of the objects in the teamselected order on the size lines. Don’t
worry if students don’t have the order of
the objects exactly correct. The goal is
to get them thinking about relative sizes.
However, if they are way off in their
order (e.g., they placed the diameter
of Earth so it is smaller than the length
of the Trans-Canadian Highway), try
to redirect them by asking probing
SE_NT_Ch01_002-073.indd Page 9 5/14/09 4:15:19 PM u-s081
/Volumes/103/KHUS024/indd%0/Nano-Technology/Chapter 1
questions such as, “Do you think the
highway is mostly straight, or do you
think it loops around the country?” and
“Does the highway fit on Earth?” Similarly, if students are way off on the small
objects, ask them probing questions (like
those above) until they have the basic
order: atomic-sized objects, molecularsized objects, and cellular-sized objects.
In the Reflect and Connect questions,
students should make analogies for
comparing the sizes of small objects by
comparing the sizes of large objects.
They will likely need some help
understanding that those objects that
align approximately vertically from the
small-object size line to the
large-object size line can be analogues
for one another. Carefully walk them
through the example using gold, a gold
nanoparticle, a human, and the Eiffel
Tower, which has been done for them.
Notes:
3. Write the order of large objects in your science notebook, from
smallest to largest.
4. What reasons did you have for ranking some objects as bigger than
others? In your science notebook, write your ideas for a few of the
objects.
For example, from looking at a globe, you can see that the width of Canada
takes up less than one-third the circumference of Earth. So the Trans-Canadian
Highway (a highway that crosses Canada) must be less than the diameter of
Earth (diameter ⴝ circumference ⴜ ␲, or about one-third the circumference).
5. Place the small-object cards face up on the table. Be sure that all team
members can easily see the cards.
6. Discuss with your team what each object is.
7. In your science notebook, sketch a picture of each object and label it,
keeping in mind the sizes of the objects. For DNA, consider its width,
rather than its length. For a sperm cell, consider its length.
Draw the smallest things as the smallest-sized pictures. For example, DNA fits
inside the cell nucleus, so DNA should be drawn smaller than the cell nucleus.
Don’t worry about making your pictures exact, just make a very simple
diagram to remind yourself about what each object is.
8. Decide as a team the order for the small-object cards (smallest on the
left, largest on the right).
Don’t worry if you don’t know the exact sizes of the small objects. Your goal
is to rank them from smallest to largest.
9. Write the order of the small-object cards in your science notebook,
from smallest to largest.
10. What have you learned about the objects that helps you decide which
objects are bigger or smaller than others? Write a few of your ideas in
your science notebook. It is OK if you don’t know how to rank some
of them.
For example, you could write, “From the hint and what we have learned
about cells, we know that DNA fits inside the cell nucleus. This is why we
think DNA must be smaller than the cell nucleus.”
11. Obtain the handout Large- and Small-Object Size Lines from your
teacher. Write the objects on the large-object size line and the smallobject size line, going from smallest to largest on both size lines.
12. Use the handout Large- and Small-Object Size Lines along with
the Size Line Protocol to answer the following Reflect and Connect
questions. The 2 size lines (large object and small object) change scale
by the same increments.
Protocol
Understanding the Science of Nanotechnology
9
Understanding the Science of Nanotechnology
9
TE_NT_Ch01_002-073.indd Page 10 6/11/09 7:51:26 PM user
/Volumes/103/KHUS025/work%0/indd%0/Nano-Technology/Chapter 1
Notes:
SE_NT_Ch01_002-073.indd Page 10 5/14/09 4:15:20 PM u-s081
/Volumes/103/KHUS024/indd%0/Nano-Technology/Chapter 1
Answers to Reflect and Connect,
SE page 10
1. See figure TEn1.1 for possible
entries.
2. Nano-sized gold particles are not the
smallest particles that exist. Many
things are much smaller than gold
nanoparticles, including atoms,
nuclei, protons, and electrons.
3. Students should recognize that they
considered the “big idea” of size
and scale. They were getting an idea
of “how big nano is” in order to
better make sense of science at the
nanolevel.
Protocol
Size Line Protocol
The large- and small-object size lines can be used to help you understand the differences
in the sizes of objects that are too small to see. On both size lines, each mark labeled with a
“10” is 10 times larger than the previous mark. This means that the objects on the large size
line can be used to make analogies for the objects on the small size line, as long as you compare objects that align vertically. The objects on the top line are 10 billion times larger than
the small objects they align with vertically. Using the size lines will help you understand
how the sizes of objects compare, even if they are all too small to see.
Step 1. Choose 2 small objects that you would like to compare in size.
Step 2. Choose 2 large objects that most closely align vertically with the 2 small objects.
Step 3. Make an analogy: the 2 small objects compare in size the same way the 2 large
objects compare.
For example: Gold atoms on your diagram align vertically with average human height.
So if a gold atom were “scaled up” so that it were 10 billion times its original size, it would
be as tall as a human being. If a gold atom were as big as a human being, then a gold
nanoparticle would be as big as the Eiffel Tower. Now you can imagine how much bigger
a gold nanoparticle is compared with a gold atom. Just imagine the difference between the
height of the Eiffel Tower and that of a human being!
Reflect and Connect
1. Copy the analogy table in figure En1.1 into your science notebook and
complete it. The first row is done for you as an example.
2. Are nanoparticles the smallest particles that exist? Why or why not?
3. Which big idea of nanoscience did you consider in this activity?
10 Understanding the Science of Nanotechnology
10
Understanding the Science of Nanotechnology
TE_NT_Ch01_002-073.indd Page 10a 6/11/09 7:51:28 PM user
Objects
1. Gold atom
2. Gold
nanoparticle
/Volumes/103/KHUS025/work%0/indd%0/Nano-Technology/Chapter 1
If the first
small object
were …
as big as
the large
object ...,
then the second
small object
would be …
as big as
second
large object.
If gold
atoms were
as big as
human
beings,
then gold
nanoparticles
would be
as big as
the Eiffel
Tower.
Picture
gold
atom
gold
nanoparticle
1. Proton
2. Gold atom
1. Proton
2. Width of
DNA
1. Proton
2. Diameter
of a human
egg cell
If protons
were
as big
as the
width of
a human
hair,
then gold atoms
would be
as large
as human
beings.
If protons
were
as big
as the
width of
a human
hair,
then the width
of DNA would
be
as large as
the distance
between
bases in a
baseball
diamond.
If protons
were
as big
as the
width of
a human
hair,
then the diameter of a human
egg cell would
be
as large as
the TransCanadian
Highway.
human
being
Eiffel
Tower
Figure TEn.:
Reflect and Connect Question 1. The main goal is to have students make analogies using the table. Don’t worry if their answers are not
exactly correct.
Understanding the Science of Nanotechnology 10a