1	Density – A Dynamic Intro to Chemistry Ed Escudero Summit Country Day School Presented at ChemEd2005
2	Rationale To challenge myself to introduce chemistry using the concept of density – a most boring topic for most students – as a means of capturing students’ interest while introducing observation skills, lab skills, communication skills, data manipulation utilizing excel and lap top computers.
3	Class Description and Layout No more than 18-20 students. The students are the top academic sophomores. 3 meetings in a 5 day rotation – 2 are 70 minute periods and 1 is a 110 minute period. A room separated into a lecture area with up to 20 desks and a lab area with 5 island work stations.
4	Most of the Demos (Inspiration)
5	Inspiration An excellent, easy to use program. Besides the diagram, one can include detailed information in the outline part of the program. Each button/icon has a set of instructions. Students are encouraged to use the program when preparing procedures for labs.
6	Inspiration Sample Procedure
7	First Set of Demonstrations Floating – Sinking Soda Cans I instruct the students to observe, digest, and write down in the “ncr” notebook a description of what they observed and, most importantly, an explanation of the observed behavior. They turn in a duplicate of their work at the end of the class period.
8	Dr. Pepper
9	7 Up
10	Mountain Dew
11	First Side Issue A student innocently asked, “How much sugar is that?” The question led to the reading of the labels and measuring out the mass of sugar listed (corn syrup, not sucrose, is actually used in the drinks). The students began a search for the “record breaking” – sugar containing drink. We now have a display of sugar in drinks.
12	Sugar in Soda/Drinks
13	Sugar in Soda/Drinks
14	Density of Gases – CO₂ Demos Generation – baking soda and vinegar Effects on a burning Fluid properties Pouring from one container to another Siphoning Pouring down a ramp Production of liquid CO₂ Snow making machine
15	Soda Associated Demo How much gas is dissolved in a typical soda/carbonated beverage?
16	Measuring Gas Dissolved in a Soda (carbonated beverage)
17	First Discrepant Event Students at this time appear a bit smug in knowing that the mass of the sugar accounts for the greater density of the sugared drinks vs the “sugar free” synthetically sweetened drinks. I then present several cans of Irish ales. (I don’t appear to have a problem using an alcoholic beverage in a demonstration.)
18	“Old” Guinness Pub Draft Ale
19	Murphy’s Irish Stout Ale
20	“New” Guinness Pub Draft Ale
21	First Take Home Assignment Each student is given an empty tennis ball container and lid. The challenge is to create a “model” which imitates the motion of the Guinness Pub Draft Ale or the Murphy’s Irish Stout. The container must float with a small portion above the surface of the water and then spontaneously flip.
22	Model – top heavy
23	Model – bottom light
24	Possible Models in action
25	Side Issue - Challenge Orbitz
26	Orbitz
27	Orbitz – A Short-lived Drink
28	Additional Demos Dancing Raisins (Sewer Lice) Diving Submarine
29	Dancing Raisins or Sewer Lice Fill a container (a tennis ball can in the video) with a clear colorless carbonated beverage. Add raisins and observe. You may be as “gross” as you wish, e.g. eat some of the “sewer lice”.
30	Resource – Ron Perkins Educational Innovations Diving Submarine Remember the submarine toys you used to find in cereal boxes? This little submarine works the same way. Powered by Baking Powder (not baking soda), it dives and surfaces just like a real submarine. As the Baking Powder reacts with the water, carbon dioxide is produced. This gas forces water out of the submarine decreasing its density and allowing it to surface. This is much the same way a real sub surfaces by purging its ballast tanks. After the sub reaches the surface, the gas bubble is allowed to escape, water takes its place, and the sub dives again. Approximately 4.5" long and wonderfully detailed, this is a great science toy for discussing buoyancy, density and the production of CO2. SUB-10 Diving Submarine - $2.95
31	Pumice For this demo, I pick up an apparently very heavy boulder. I really strain to pick up the rock. When I get it to the fish tank, I carefully put it in, and, even though it appeared to be heavy, it floats.
32	Resource – Ron Perkins Educational Innovations Giant Pumice This is it. The largest volcanic Pumice sample we have ever seen... and it still floats. In fact, during the spring thaw in the mountains of Oregon, you can see these huge pieces of pumice floating down the rivers! A strange sight indeed. This stuff makes a great density demonstration -- one your students will remember for a long time. Totally cool! Use with our Ironwood Samples for a fun and thought provoking lesson; the rock that floats with the wood that sinks! RM-300 Giant Pumice - $19.95 RM-300A Melon-Size Pumice - $14.95
33	Resource – Ron Perkins Educational Innovations Floating Coins A great surface tension demonstration, these real Japanese 1 Yen coins are made from aluminium and can be made to float on the surface of a cup of water. Simply use a paper clip to gently lower the coin into the water and it will float on the surface. Adding a drop of liquid dish washing soap destroys the surface tension and causes the coin to sink. Includes suggested activities. YEN-110 Floating Coins (50 Coins) - $6.95
34	Resource – Ron Perkins Educational Innovations Ironwood Samples Ironwood is a very rare wood which grows in certain Southwestern desert regions of the United States. With a density approximately 1.28g/cc, this unusual wood sinks in water and makes a great density lesson. Use with our Giant Pumice for a fun and thought provoking demonstration; the rock that floats with the wood that sinks! Super dense woods are naturally occurring materials. Exact density of individual samples may vary. FE-12 Ironwood Samples (~ 135 g) - $9.95
35	Resource – Ron Perkins Educational Innovations Lignum Vitae Wood Density Samples Lignum Vitae is an extremely dense wood that is imported from Brazil. It can have a density as high as 1.39 g/cc. One of the few species of wood that sink in water, it is interesting to use as a density specimen. Super dense woods are naturally occurring materials. Exact density of individual samples may vary. LV-100 Lignum Vitae Wood Density Samples (~ 135 g) - $9.95
36	Temperature Effects on Density Galilean Thermometer Lava Lamp Phase Change – Water Freezing Density Paradox
37	Galilean Thermometer
38	Galilean Thermometer
39	Lava Lamp
40	Lava Lamp
41	New Tool – IR Thermometer IR Thermometers determine temperature by measuring the black body radiation given off by substances above absolute zero. Black body radiation is a function of both the temperature and the emissivity of an object. The instrument is set for an emissivity of 0.95 which is common for objects other than metals or shiny surfaces. To measure the temperature of a metal requires aiming at a piece of 3M black tape placed on the object. Because temperature is determined quickly, without direct contact, these thermometers were used to pre-screen travellers to stop the spread of the SARS Virus!
42	Resource – Ron Perkins Educational Innovations Density Paradox Something To Ponder! This is an awesome discrepant event for your most advanced 'density' students! When this solid white object is placed in water, it initially sinks. Wait about 60 seconds, and it mysteriously floats to the surface. When removed and placed in different water, it continues to float initially and, in about 60 seconds, mysteriously sinks. Why? How can this be? Great for demonstrating how temperature can affect an object's density! In the experiment described above, the first beaker contained hot water from the tap; the second beaker contained ice water. DEN-300 Density Paradox (set of two) - $9.95
43	Effect of a Phase Change On Density What is the effect of freezing a container completely filled with water. The picture is the student view of the experimental set-up.
44	Effect of a Phase Change On Density Purchase at a hardware store one 90^o elbow for each demonstration Two, re-usable end caps A Styrofoam container (one gallon acid shipping container)
45	Results of the Phase Change On Density
46	Finale – Density of a Kid The unit culminates with the determination of the density of a student volunteer. You need to obtain: A 40-50 gallon sturdy trash can A baby pool 2000 – 100 mL graduated cylinder Garden hose for filling the trash can Digital bathroom scale
47	Setup
48	Mass measurement
49	Mass Measurement
50	Insertion
51	Insertion
52	Insertion
53	Insertion
54	Insertion
55	Insertion
56	Insertion
57	Extraction
58	Volume Measurement
59	Volume Measurement
60	Volume Measurement
61	Volume Measurement
62	Volume Measurement
63	Data Recorder
64	Results – excel spreadsheet
65	Results – excel spreadsheet
66	Take Home Activity – First Quarter After viewing the Bob Becker video on Cartesian Diver-sions, the students are assigned the task of creating a Cartesian Diver of their own. Minimum passing grades will be assigned to the simplest diver – eye dropper or beral pipet in a bottle. Other grades will depend on the creativity manifested in the project.
67	Cartesian Divers
68	Cartesian Divers
69	Cartesian Divers
70	Cartesian Divers Applications: The intake and discharge of water in a submarine allows it to rise or fall in the water. Although this isn’t related to Pascal’s principle, the concept of more or less air in a rigid container is applicable. Cf. Diving Submarine from Educational Innovations. Cf. Show video clip from Bob Becker’s Twenty Demonstrations Guaranteed to Knock Your Socks Off, as well as Demonstration XV. Cartesian Diversions – Creative Explorations Into an Age-Old Amusement on pages 40-43 of the book. Both book and video are available from Flinn Scientific. Construction of a Cartesian Diver becomes the next take home project.
71	Cartesian Diver Resources
72	Buoyancy Effect of Immersing an Object in Water Mass of brick in air = 2449 g
73	Buoyancy Effect of Immersing an Object in Water Mass of brick submerged in water = 1400 g
74	Buoyancy Effect of Immersing an Object in Water Apparent loss in mass of the brick (mass in air – mass in water) = 1409 g How do we account for the loss in mass?? (sig figs ??) Volume of Brick = Length x Width x Height = 8 in x 4 in x 2 in = 64 in³ Converting to cm³: 64 in³ x (2.54cm/in)³ = 1049 cm³ Mass of water displaced = vol x density = 1049 cm³ x 1.0 g/ cm³ = 1049 grams Note that the mass of the water displaced by the brick matches the apparent loss in mass of brick when submerged under water. Any object weighed under water will weigh less than when weighed in air. The difference is always the mass of the water displaced.
75	Laboratory Activities After the demos, the students are grouped and begin to perform lab activities set up at each of the 5 lab stations.
76	List of Laboratory Activities Density Mystery Lab – 15 black “plastic” specimens. Density and Slope Lab – 4 aluminum cylinders and 4 “plastic” cylinders. Density Identification Lab – a set of 15 different cylinders. Each cylinder assigned to a different student. Densities and descriptions of the items is available.
77	Resource – Ron Perkins Educational Innovations Density Mystery Set Why is my density result different from yours? What am I doing wrong? Who is correct? Ask students to determine the density of 15, identical looking, black plastic specimens of various sizes. Results will vary (hopefully)! When mass vs. volume is plotted for our Density Mystery Set, two lines with different slopes result. Although they look the same, this set is comprised of two different plastics, one with a density of 1.1 and the other with a density of 1.4. At the conclusion of the lesson, the pieces can be dropped into salt-water... seven sink and eight float. A great lesson in scientific truth and trusting your own calculations! DEN-200 Density Mystery Set - $39.95
78	Resource – Ron Perkins Educational Innovations Density & Slope Set Great for showing the difference between accuracy and precision!! Students can determine the density of two different materials: aluminum and a gray colored plastic. Plot mass vs. volume. Density is the slope of the line. The set contains four different sized samples of each material for a total of eight specimens. You will need a balance to determine the mass and either a ruler or a graduated cylinder to determine the volume. DEN-40 Density & Slope Set - $19.95
79	Resource – Ron Perkins Educational Innovations Density Identification Set Students try to identify each of 15 different samples by determining their density. Each sample cylinder varies in size (volume) and density, has a diameter of 1.5 cm and varies between 4 and 7 cm in length. Set includes: Aluminum, Copper, Brass, Polyurethane, Acrylic, Teflon plus 9 others. DEN-210 Density Identification Set - $39.95
80	List of Laboratory Activities Density Cube Lab – Identify metallic cubes based on density. List of metals used is available. Salt Sense – Is there really 33% less sodium in Salt Sense than in regular Salt. Two Steel Spheres – Same? Different? Which Floats
81	Resource – Ron Perkins Educational Innovations Density Cubes - Six Metals Students identify metal cubes by determining their density. This is a classic lab now available from EI with extra large (easy and accurate to measure) 25 mm cubes of 6 different metals. Each set includes one cube each: aluminum, brass, copper, iron, lead, and zinc. Plus, students can use the density of the samples to calculate the purity! DEN-220 Density Cubes - Six Metals - $18.95
82	Salt Sense
83	Salt Sense Is there really 33% less sodium in Salt Sense than in regular salt? Write down your procedure in your lab notebook. Use a new clean page. Materials available to you: 25 mL graduated cylinders balances mortar and pestle powder funnels rubber policemen Show your calculations proving or disproving the claim.
84	Resource – Ron Perkins Educational Innovations Steel Sphere Density Kit How are they the same? How are they different? One floats and one doesn't! Which is which? Great for teaching the skills of observation and deduction! Although these two shiny, metal spheres have about the same mass, one has a diameter of 2.86 cm and the other a diameter of 12.7 cm making their densities vastly different. Seeing the large one float in water seems unbelievable! Students can't put these down. Great for teaching that density depends on BOTH mass and volume. Another NSTA best seller! Bowl not included. DEN-350 Steel Sphere Density Kit - $19.95
85	Supplemental Activities/Labs Floating Density Sphere Lab – for those who complete the “neutral buoyancy” home lab – bonus. Speed of Bubble Tube Lab Archimedes Balance Lab Mixture Separation Challenge Bowling Ball Challenge
86	Resource – Ron Perkins Educational Innovations Density Sphere Experiment Kit This totally awesome kit is designed to permit students to discover and apply concepts of density and buoyancy. In this kit students make a density gradient from sugar or salt in a plastic column. Students then float 5 small spheres of different densities in the solution. Each sphere floats at a different level! By manipulating the density gradient, students can change the level at which the spheres float. Kit includes full instructions and write-up as well as spheres made of the following materials: polyethylene, polystyrene, nylon, acrylic and cellulose acetate. Even unknown plastics are included for student density determination. Great for an elementary science table or as a terrific lab for middle school, high school or college. DEN-10 Density Sphere Experiment Kit - $9.95
87	Resource – Ron Perkins Educational Innovations Speed of the Bubble Tube Set The Speed of the Bubble Tube Set consists of three 22-inch-long transparent plastic tubes containing colored fluids with three different viscosities. A bubble in each tube rises at a constant speed which depends on the type of fluid, the angle at which the tube is inclined and, to some extent, the temperature. This great introductory activity gives students practice setting up experiments, graphing data and making predictions. Each set of tubes comes with complete instructions. Perfect for teaching the concepts of precision, accuracy, graphing, slopes, uncertainty and extrapolation. Great beginning of school activity for science students of all ages.
88	Resource – Ron Perkins Educational Innovations Archimedes Balance Measure mass and volume of a wide variety of materials: rocks, paper clips, seawater, shampoo, etc. This leads to surprisingly accurate deter-inations of density. (D-M/V) Based on Archimedes Prin-ciple, the balance consists of a graduated cylinder with an additional tube that floats in it. No other equipment is needed! When used to determine the density of a sample of aluminum, we arrived at an answer of 2.7 g/ml - just as reported. Comes with full instruction and a sample of aluminum.
89	Resource – Ron Perkins Educational Innovations Mixture Separation Challenge Using only table salt and water, students are asked to develop a method for separating this mixture of four different small plastic beads. Advanced students can continue on to determine the density of each different polymer! The material in this brand new separation lab can be used over and over again, and because only polymer materials are used, cleanup is as easy as ever. Complete teacher instructions provided. Includes 230 g (1/2 lb) of mixture... , enough for a class of 24 students working in pairs. MIX-100 Mixture Separation Challenge - $19.95
90	Bowling Ball – Sink or Float
91	Bowling Ball Sink or Float
92	Misc. Lab/Demo Resources Digital Caliper Classroom Density Assortment Extra Sets of 15 Specimens
93	Cas-Ker Electronic Digicaliper Measures in inches .001-6 in. or millimeters .01-150mm Measures inside , outside and depth. Operates on one SR44 cell, included. Auto-off. Stainless steel construction. Thumb wheel, lock screw, data hold.
94	Resource – Ron Perkins Educational Innovations Classroom Density Assortment Our new 48-piece density set provides four different sized specimens for each of twelve different materials. Each set of 4 density samples comes in its own tube for easy of classroom management. Measuring the mass and volume of each sample specimen allows students to plot Mass vs. Volume, and thus, determine the density of their individual material by calculating the slope of the resulting line. Materials include: aluminum, PVC, acrylic, wood, polypropylene, phenolic, polyurethane and Teflon. DEN-952 Classroom Density Assortment - $99.95
95	Resource – Ron Perkins Educational Innovations Extra Sets of Fifteen Density Specimens With Storage Base Each set contains 15 specimens of varying lengths. Polypropylene is the only one with a density less than water; it floats. DEN-100 Set of 15 Aluminum Density Specimens w/base (2.7 g/cc) - $49.95 DEN-110 Set of 15 Brass Density Specimens w/base (8.6 g/cc) - $59.95 DEN-120 Set of 15 PVC Density Specimens w/base (1.4 g/cc) - $39. DEN-130 Set of 15 Polypropylene Density Specimens w/base (90 g/cc) - $39.95
96	Resource – Brian Rohrig
97	Resource 150 Captivating Chemistry Experiments Using Household Substances ISBN 0-9718480-2-5 150 easy, effective, and highly entertaining science experiments that can be performed with ordinary household substances! $ 18.95
98	150 Captivating Chem. Exp. Using Household Substances Does Hot Water Rise? Sink or Float? Bobbing Raisins How Much Gas in a Can of Soda Is Salt Water Denser than Pure Water? Layers of Liquids Cartesian Diver
99	150 Captivating Chem. Exp. Using Household Substances How to Make a Heavy Balloon Fun with Carbon Dioxide Neutral Buoyancy: Part 1 Neutral Buoyancy: Part 2
100	Resource – Brian Rohrig 150 More Captivating Chemistry Experiments Using Household Substances ISBN 0-9718480-1-7 Another book of 150 easy, effective, and highly entertaining science experiments that can be performed with ordinary household substances! $ 18.95
101	150 More Captivating Chem. Exp. Using Household Substances The Incredible Expanding Ivory Soap A Liquid Rainbow The Magic Balls Is Hot Air Less Dense than Cold Air? A Miniature Submarine Ketchup Packet Cartesian Diver The Floating Golf Ball
102	150 More Captivating Chem. Exp. Using Household Substances The Great Grape Race A Miniature Lava Lamp Is It Really Gold? Bowling for Density Neutral Buoyancy Does Clay Float? Is Hot Water Less Dense than Cold Water
103	150 More Captivating Chem. Exp. Using Household Substances The Rising Pop Can Overflowing Ice Cubes The Mysterious Grapes Does Ice Melt Faster in Fresh Water or in Cold Water?
104	Resource – Brian Rohrig 101 Intriguing Labs, Projects and Activities for the Chemistry Classroom Includes many take-home labs. Teachers may photocopy for classroom use. $ 12.95
105	101 Intriguing Labs, Projects, & Activities for the Chem. Classroom Dramatic Density Demo Density of Solids Lab Density of Liquids Lab Class Activity: Determining Density of a Person Take Home Lab: Density Column Class Activity: Achieving Neutral Buoyancy
106	Resource – Brian Rohrig 39 Dazzling Experiments with Dry Ice Learn about the many fascinating uses of this incredible substance. $ 12.95
107	Resource – Brian Rohrig Fizz Factor: 50 Amazing Experiments with Soda Pop (With Steve Spangler) 50 fizzy, explosive and tasty experiments with regular soda pop! $ 14.95
108	Resource – Brian Rohrig 39 Fantastic Experiments with the Fizz-Keeper (Fizz-Keeper included) This manual contains many unique and creative experiments that can be accomplished with a $ 16.95
109	Resource – Brian Rohrig Pure Slime : 50 Incredible Ways to Make Slime Using Household Substances Make slime in your own home with these easy to do experiments! $ 12.95
110	Resource – Brian Rohrig 39 Amazing Experiments with the Mega-Magnet (magnet included) This fully illustrated manual comes with a Mega-Magnet, considered one of the worlds most powerful magnets. $ 16.95
111	Resource – Flinn Catalog Flinn Chemical and Biological Catalog Reference Manual 2005 Flinn Scientific Inc. P.O. Box 219 Batavia, IL 60510 1-800-452-1261 FAX (866) 452-1436 flinn@flinnsci.com
112	Resource - Flinn Archimedes Balance (AP6220) Class set 35.50 Density Cube Set (AP6058) $21.95 Density Rod (AP4632) $14.95 Reverse Density Rod (AP6069) $9.95 Density of Solids Kit (AP4615) $9.35 (AP6148) Classroom set $115.00 Equal Mass Kit (AP4636) $9.00 (AP6147) Classroom set $99.95 Measurement Challenge – A Density Laboratory Kit (AP5939) $47.95 Specific Gravity Block Set (AP5714) $27.50
113	Twenty Demonstrations Guaran-teed to Knock Your Socks Off Vol 1 X. Instant Hot Air Balloon XI. An Eggs-splosive Demonstration XIII. Flame Tornado XIV. A Densi-Tee XV. Cartesian Diver-Sions XVI. Methane Mamba
114	Twenty Demonstrations Guaran-teed to Knock Your Socks Off Vol 2 XVI. Misty Smoke Rings XVII. Flaming Vapor Ramp XVIII. Pouring and Siphoning a Gas