Teacher Name:
School Campus / ISD Name:
Classroom Subject:
Grade Level:
Time Frame:
Linda Kelly
John Marshall High School / Northside ISD / San Antonio, TX
Chemistry pre-AP and Physics I
10-11
3 to 4 days during the first six weeks of school
End-of-Summer Report
Overview: My E3 laboratory assignment consisted of viewing ammonium perchlorate crystals
(used in rocket propellant) under a light microscope and photographing the crystals. I used
Photoshop, IQ Materials software, and Excel to gather data and calculate the particle size and the
distribution of these sizes. From this work, I propose to have the chemistry and physics students
perform a similar investigation. I believe this research is relevant to my students because they
continually ask, “Are we going to blow something up?” Almost everyone in interested in rockets
or have seen fireworks displays. Because of my lab experience, I can better explain some of the
synthesis procedures in creating rocket propellant. Likewise, I can explain the importance of
using exacting measurements, record keeping, and repeated trials (not just doing one trial as time
constraints in a classroom setting permit). The students would complete a pre-Test of
calculations and engineering questions. I would show a PowerPoint presentation explaining my
actual lab research. During whole-class-instruction, I would discuss quantities, solve some metric
conversions, demonstrate how to use the electronic balance, and how to read a meniscus with a
graduated cylinder. The students would collect their data and make graphs in the next two class
periods. Then I would end this lesson with a post-test.
TAKS Science Objectives: 1 (Nature of Science) 4 (Chemistry)
Math Objectives: 4 (equations & inequalities) 8 (measurement & geometry) 9 (Statistics)
TEKS: Chemistry 1,2,3 (investigations & measurement) Physics 2
Math +,-,x,/
Technology: All groups graph the size distribution of particles in the sample using
Excel spreadsheet and graphing capabilities; calculators
Task: Students will determine the mathematical attributes and size distribution of a sample of
“rocket propellant.” Given samples, students determine mass, volume, density, surface area, size
distribution. Students will use appropriate units, use significant figures, write scientific notation,
show sample calculations, graph surface area vs. distribution of particles.
My classroom project consists of groups of students measuring and solving calculations
independently and simultaneously. Students will engage in lecture, hands-on laboratory
investigations, cooperative learning, problem solving, technology integration, and
communicating results. As a class, we will determine which method gives the better results:
direct or indirect measurement.
Procedure:
Set A: Half the students (8 lab groups of 2 students/group) will gather data from direct
measurement. Students will measure diameters, mass, measure volume by water displacement,
calculate radius, density, surface area of their sample; graph particle size distribution by counting
and calculation.
Set B: Half the students (8 lab groups of two’s) will gather data through indirect measurement
via a photograph and centimeter ruler. Students will measure diameters, find radius, use the
formula for “volume of a sphere” to calculate volume. Given the total mass of a sample and the
percent of each size, students would perform percent by mass calculations to determine the mass
of each size of particles. Students must collect data for a representative sample—one
measurement is not enough.
Challenge: Which method (actual counting vs. photography) will give the best results in a
timely manor? I hope that the results from similar samples will correspond using these different
methods. Given the lab equipment, I expect the students to develop their own procedures for
collecting data.
Lab equipment: electronic balances, beakers, graduated cylinders, water, rulers, computers
Teacher set up: Glass Pearl Beads (Wal-Mart jewelry craft #36402 $8.96 / 285 g of beads)
Plastic Petri dishes (60mm from biology lab or Analytical Scientific $13.99 / 20 )
Place beads (several small, medium, large) in dishes. Tape lids to bottoms.
A sample may include beads of varying sizes, different colors (contaminants present), not filling
the dish completely (deal with mobile particles), beads stuck in a matrix of slime or Elmer’s
Glue (cannot remove beads out of environment), another foreign substance being mixed with the
beads, etc.
Assume all the small beads are the same; all the medium beads are the same, all the large beads
are the same. Assume beads are perfect spheres.
Take a digital photo of each of the samples. Reduce or enlarge the photo until a printed
version measures bead size at 10, 8, 6 mm. The students will have to physically measure
diameters of the particles and calculate volume and surface area of spheres. I do not know how
they calculate density from a photo unless mass is given. However, given the total mass of the
sample and percent distributions of the particles, students can calculate percent composition of
each size. (43 % are large beads x 14.23 g total mass = 6.119 g attributed to all the large beads.)
Correlations: 1. The sample is a chemical crystal. Calculate the actual size of an average
crystal in micrometers ( μm ) using scientific notation.
2. The sample represents an image received from the Hubble telescope.
Calculate the actual size of an average star in kilometers ( km ) using scientific notation.
Evaluation: The investigation would be evaluated by the precision of several classes of students
calculating the average size of the samples. The lab would be evaluated by the accuracy of the
student answers and meeting the challenge of which method derives the best answers in a timely
manor.
Expected Outcomes: I expect the students will be reluctant to perform a lab without directions,
but then to attempt measuring when they see others working. I expect the students to perform the
objectives as stated in the TEKS. I expect better results from direct measurement because
photographs of spheres may be distorted due to parallax. I expect students to appreciate the many
measurements researchers must make in order to find a true meaning in their data. I expect the
students to answer more post-test questions correctly. I expect the students to gain a better
understanding of the work of a researcher, scientist, or engineer. I expect the students to have fun
working together.
Supplemental pages following: Direct Measurement Data page
Indirect Measurement Data page
Particle Size Lab
Direct Measurement Data
sample # _______
names______________________________
Measure the sizes of the particles in your sample. Then calculate the average for one particle. Be sure to
specify units.
Mass
____ Large = _____________
avg = _______________
____ Med = _____________
avg = _______________
____ Small = ______________
avg = _______________
____ Total = ______________
Volume
____ Large = _____________
avg = _______________
____ Med = _____________
avg = _______________
____ Small = ______________
avg = _______________
____ Total = ______________
Density
____ Large = _____________
avg = _______________
____ Med = _____________
avg = _______________
____ Small = ______________
avg = _______________
____ Total = ______________
Surface Area The formula for surface area of a sphere is __________________
Given the volume, find r
____ Large = _____________
avg = _______________
____ Med = _____________
avg = _______________
____ Small = ______________
avg = _______________
____ Total = ______________
Graph of distribution Surface Area vs. particle size
Particle Size Lab
Indirect Measurement Data
photo # _______
names______________________________
Measure the sizes of the particles in your sample. Then calculate the average for one particle. Be
sure to specify units.
Mass
decimal percent x total mass = mass of one particle
____ Large = _____________________
avg = _______________
____ Med = _____________________
avg = _______________
____ Small = ______________________
avg = _______________
____ Total = ______________________
Volume The formula for the volume of a sphere is _____________________
____ Large = _____________
avg = _______________
____ Med = _____________
avg = _______________
____ Small = ______________
avg = _______________
____ Total = ______________
Density
____ Large = _____________
avg = _______________
____ Med = _____________
avg = _______________
____ Small = ______________
avg = _______________
____ Total = ______________
Surface Area The formula for surface area of a sphere is __________________
____ Large = _____________
avg = _______________
____ Med = _____________
avg = _______________
____ Small = ______________
avg = _______________
____ Total = ______________
Graph of distribution of Surface Area vs. particle size