It’s The Law!

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2007: Exploring the Inner Space of the Celebes SeaIt’s the Law!FocusMaximum Number of StudentsGas Laws30Grade LevelKey Words7-8 (Physical Science)Celebes SeaSCUBA divingGas lawsBoyle’s LawCharles’ LawGay-Lussac’s LawHenry’s LawDalton’s LawPressureClass discussionFocus QuestionHow do Boyle’s Law, Charles’ Law, Gay-Lussac’sLaw, Henry’s Law, and Dalton’s Law have practical application to SCUBA diving?Learning ObjectivesStudents will be able to define the basic principles stated in Boyle’s Law, Charles’ Law, GayLussac’s Law, Henry’s Law, and Dalton’s Law.Background InformationStudents will be able to explain the applicationof Boyle’s Law, Charles’ Law, Gay-Lussac’s Law,Henry’s Law, and Dalton’s Law to observations orevents related to SCUBA diving.Indonesia is well-known as one of Earth’s majorcenters of biodiversity. Although Indonesia covers only 1.3 percent of Earth’s land surface, itincludes: 10 percent of the world’s flowering plantspecies; 12 percent of the world’s mammal species; 16 percent of all reptile and amphibianspecies; and 17 percent of the world’s bird species.MaterialsNoneAudio/Visual MaterialsNoneTeaching TimeIn addition, together with the Philippines andGreat Barrier Reef, this region has more speciesof fishes, corals, mollusks, and crustaceans thanany other location on Earth.Two or more 45-minute class periods (seeLearning Procedure, Step 3)Seating ArrangementClassroom styleWhat, exactly, is meant by biodiversity, and whyis it important? The term “biodiversity” is usuallyunderstood to include variety at several levels:

2007: Exploring the Inner Space of the Celebes Sea – Grades 7-8 (Physical Science)Focus: Gas laws variety of ecosystems: high biodiversity suggests many different ecosystems in a givenarea; variety of species: high biodiversity suggestsmany different species in a given area; variety of interactions between species; and variety within species (genetic diversity): highbiodiversity suggests a relatively high level ofgenetic variety among individuals of the samespecies.oceanexplorer.noaa.govoften divide the ocean water column into threezones: the “epipelagic zone” (also called the“sunlit” or “euphotic” zone) from the surface to adepth of about 200 m; the “mesopelagic zone”between 200 m and 1100 m; and the “bathypelagic zone,” which is deeper than 1100 m.“Plankton” is a general term for organisms thatdrift or swim weakly in midwater environments,and includes plants (phytoplankton) as well asanimals (zooplankton). Phytoplankton includemajor primary producers in aquatic food webs,and zooplankton are often the primary consumers that are a key link in transferring energy toother consumers in these food webs. Despite theirimportance, many types of zooplankton are notwell-understood. This is partially because manyzooplankton are fragile, jelly-like creatures thatare easily damaged by nets and other devicesthat are traditionally used to collect midwateranimals for study. Scientists participating in the2007: Exploring the Inner Space of the CelebesSea Expedition plan to use techniques known asblue-water diving to observe and collect fragilemidwater animals.A simple definition of biodiversity could be “Thevariety of all forms of life, ranging in scale fromgenes to species to ecosystems.”Biodiversity is important to humans because oursurvival depends upon many other species andecosystems. Some examples of our dependenceon biodiversity include: fresh air containing oxygen; clean water; productive soils; food, medicines and natural products; natural resources that provide the basis forhuman economies; and natural beauty that improves our quality oflife.(adapted from the Biodiversity Project, )Diving in the open ocean is quite different fromnearshore diving, because there are no objectsfor visual reference, and it is very easy for diversto become disoriented. “Blue-water diving” techniques involve a system of lines and floats to create visual reference points, as well as proceduresthat help keep divers in touch with each other.One diver (called the “safety diver”) holds analuminum “trapeze,” and descends to the desireddepth along a weighted line attached to a surface float. Other divers are attached to safetylines that clip onto the trapeze. This system allowsthe safety diver to keep track of the “working”divers who are free to concentrate on researchtasks.Quite a lot is known about Indonesia’s terrestrialand shallow-water ecosystems. But scientific knowledge and understanding of midwater ocean communities is generally sketchy, and many midwateranimals have not been studied at all—even thoughthe midwater ocean environment is our planet’slargest ecosystem. Midwater animals range frommicroscopic zooplankton to the largest animals onEarth, provide a major source of nutrition for benthic (bottom) communities, and are an importantlink in the transfer of energy and materials from thetop to the bottom of the ocean. Note that the term“midwater” as used here includes the entire watercolumn, but the same term has also been used torefer to only part of the water column. ScientistsEven with such specialized techniques, diverswho use self-contained underwater breathingapparatus (SCUBA) still must be aware of how

oceanexplorer.noaa.gov2007: Exploring the Inner Space of the Celebes Sea – Grades 7-8 (Physical Science)Focus: Gas lawsgases behave under pressure, and how the basicgas laws apply to SCUBA diving. In this lesson, students will be introduced to Boyle’s Law,Charles’ Law, Gay-Lussac’s Law, Henry’s Law,and Dalton’s Law, and how these laws affectSCUBA note the safety precautions for this activity:allow for some gas escape, do not screw thelid onto the container so tightly that the gaspressure could cause the container to burst,and do not use a glass container (clear plastic is safer).Learning Procedure Dalton’s Law: For a “virtual experiment,” sLaws/DaltonsLaw.html1. To prepare for this lesson, review the introductory essays for the 2007: Exploring the InnerSpace of the Celebes Sea Expedition at ppines/. You canview many images of planktonic organisms s/, but beaware of copyright restrictions posted on theWeb site.You can find other “virtual demonstrations” forgas laws at Briefly introduce the 2007: Exploring the InnerSpace of the Celebes Sea Expedition, focusingon the importance of midwater animals andwhy these animals have not been well-studied.You may want to briefly describe the problemsof SCUBA diving in the open ocean and someof the blue-water diving techniques used toovercome these problems.Numerous demonstrations have been created tointroduce various gas laws, and are describedon many Internet Web sites. Some of these usespecialized apparatus, while others are quitesimple. Many instructors have their own favoritegas law demonstrations. If you do not, the following may be useful: Boyle’s Law: The “Cartesian Diver” is oneof the classic demonstrations; see file 59 ofthe Royal Society of Chemistry’s “ClassicChemistry Experiments” ( exp.htm). For an animateddemonstration of Boyle’s Law, see tml3. Using the demonstrations referenced in step1, or your own favorites, introduce students toBoyle’s Law, Charles’ Law, Gay-Lussac’s Law,Henry’s Law, and Dalton’s Law. Note that insome standards and texts, the first three lawsmay be combined as the Combined Gas Law:P1 V1 P2 V2T1 Charles’ Law: A glass bottle, balloon, andheat source are all you need; see charles.html; for a quantitative demonstration, see 4.htmlT2Where P absolute pressure, V volume, andT absolute temperatureIf students are unfamiliar with the behaviorof gases, it may be easier to consider thesefactors two-at-a-time (i.e., as three separate“laws”). Gay-Lussac’s Law: Several ways to do the“egg in a bottle” trick; see e.htmlAt the conclusion of each demonstration, challenge students with the following problemsrelated to SCUBA diving, and lead a discussionof students’ answers. You may want to have Henry’s Law: For a demonstration involving root beer, see 02005.pdf. Please be sure

2007: Exploring the Inner Space of the Celebes Sea – Grades 7-8 (Physical Science)Focus: Gas lawseach student write their own response to theproblems prior to group discussion. Dependingupon the amount of discussion and students’grasp of the individual gas laws, this activitymay require several class periods.oceanexplorer.noaa.govbuoyant, so she has to put some air into herBC to compensate. When she ascends, thepressure decreases and her wetsuit becomesmore buoyant. In addition, the volume ofthe air she put into her BC also increases,making her BC more buoyant. So she has torelease air from her BC, or else she wouldpop to the surface like a cork! This could bereally bad, because Discussions should include the following points:(a) Boyle’s LawChallenge Question:SCUBA divers often wear a wet suit to help keepthem warm while diving. A wet suit is made offoam rubber or similar material that traps smallair bubbles. The air bubbles provide insulation,but also cause divers to float. To overcome thetendency to float, divers carry weights. But asdivers descend, their wet suit becomes less buoyant. When this happens, the problem is howto deal with the weights they brought from thesurface. Most divers blow air from their tank intoan inflatable vest called a buoyancy compensator (“BC” for short) to balance the extra weight.When a diver returns to the surface, she has torelease air from her BC to keep from rising tooquickly. How does Boyle’s law explain what happens to the wet suit and BC? Hint: The pressureon a diver’s body increases by one atmospherefor every ten meters of depth. So at the surface,a diver is under a pressure of one atmosphere(about 14 lb per square inch). Ten m down, thediver is under a pressure of two atmospheres;20 m down, the pressure is three atmospheres,and so on. Boyle’s Law is also important to diversbecause it means that if a diver takes a lungful of air while he is underwater, that air willexpand in his lungs as he rises to the surface.If he holds his breath, or ascends too rapidly(like a cork) the expanding air can rupturehis lungs. So the golden rules of diving are:Never hold your breath, and don’t ascendmore rapidly than your smallest bubbles.(b) Charles’ LawChallenge Question:As SCUBA divers descend, they often encounterlayers of water that are significantly colder thanwater at the surface. Suppose a diver blows airinto his BC at the surface until he is neutrallybuoyant (which means he neither rises nor sinksin the water). As he swims deeper, he enters alayer of much colder water, and soon finds thathe is sinking rapidly through the water. Howdoes Charles’ Law explain what happened?Discussion points: Charles’ Law states that the volume of a givenamount of gas is directly proportional to theKelvin temperature, provided the amount ofgas and the pressure remain fixed.Discussion points: Boyle’s Law states that the product of the volume and pressure of a gas held at a constanttemperature is equal to a constant (PV k).So, if the pressure of the gas doubles, thevolume will be decreased by half; and if thevolume of a gas doubles, the pressure mustdecrease by half. As the diver enters colder water, the temperature of the air in his BC is reduced. Charles’Law predicts that the volume of air will alsobe reduced in proportion to the change intemperature. Since buoyancy depends uponthe volume of air in the BC, buoyancy willalso be decreased, causing the diver to sink. As a diver descends, the pressure increases,so the volume of the air bubbles in her wetsuit decreases. This makes the wetsuit less

oceanexplorer.noaa.gov2007: Exploring the Inner Space of the Celebes Sea – Grades 7-8 (Physical Science)Focus: Gas lawsa bottle of soda to visualize what “undissolve”looks like (the dissolved substance forms bubbles as it changes back into a gas state).(c) Gay-Lussac’s LawChallenge Question:A careless diver leaves a full SCUBA tank in thetrunk of a car during a hot summer day. Afterseveral hours, a deafening whistle comes fromthe trunk and the diver finds that her tank isempty. She says, “Man, I should have expectedthis to happen because of Gay-Lussac’s Law!”What did she mean? Henry’s Law predicts that gases dissolved inthe diver’s blood under three atmospheres ofpressure will “undissolve” when the pressure isreduced to one atmosphere (at the surface). Infact, if the diver ascends too rapidly, bubbleswill form in her blood and may cause decompression sickness (also known as “the bends”).This is why divers must ascend slowly, andsometimes must pause for a while at shallowerdepths, to allow time for the dissolved gases toleave their blood without forming bubbles (likevery slowly removing the cap from a bottle ofsoda).Discussion points: Gay-Lussac’s Law states that for a fixedamount of gas (fixed number of moles) at afixed volume, the pressure of the gas is proportional to the temperature. When a filled SCUBA tank is heated, theamount of gas stays the same, and so doesthe volume of the tank, but the pressure insidethe tank increases as the temperature rises.Eventually, the pressure can reach the pointat which the safety disk inside the tank valveruptures, allowing the air inside the tank toescape; and making a very loud noise as itdoes so!(e) Dalton’s LawChallenge Question:Ordinary air contains about 78% nitrogen,21% oxygen, and small amounts of severalother gases. As a diver descends, the pressureof the air he is breathing increases by aboutone atm for every 10 m of depth. Oxygen maybecome toxic and cause convulsions if it isbreathed at a pressure above 1.4 atmospheres.According to Dalton’s Law, at what depthshould a SCUBA diver be concerned about oxygen toxicity if he is breathing ordinary air?(d) Henry’s LawChallenge Question:At a depth of 20 m, a SCUBA diver’s body isexposed to a pressure of three atmospheres.If the diver is breathing ordinary air, she isbreathing a mixture of several gases; mostlynitrogen (%), and oxygen (%). Suppose thediver remains at this depth for one hour, andthen returns to the surface. What does Henry’sLaw predict will happen to gases dissolved inthe diver’s blood?Discussion Points: Dalton’s Law states that the pressure exertedby a mixture of gases is equal to the sum ofthe pressures that would be exerted by thegases individually. Since air contains about 21% oxygen, so thepressure of oxygen at the surface is about0.21 atmosphere. Since pressure increasesby one atmosphere for every 10 m of depth,the relationship between depth and pressureis(pressure) 1 atm (depth in m) (10 m/atm)Discussion Points: Henry’s Law states that the mass of a gas whichdissolves in a volume of liquid is proportionalto the pressure of the gas. So, as the pressuregoes up, more gas will dissolve; and as thepressure decreases, some of the dissolved gaswill “undissolve.” Imagine taking the top off of

2007: Exploring the Inner Space of the Celebes Sea – Grades 7-8 (Physical Science)Focus: Gas lawsSo the pressure of air at 10 m would be1 atm (10 m) (10 m/atm) 2 atmoceanexplorer.noaa.govfor SCUBA diving at 1673.Multimedia Learning Objectsand the pressure of oxygen at 10 m would be(21% O2) (2 atm) 0.42 atm O2 – Click on the linksto Lessons 8 and 12 for interactive multimediapresentations and Learning Activities on OceanCurrents and Food, Water, and Medicine fromthe Sea.So, the depth at which oxygen would have apressure of 1.4 atm is(depth in m) [ (1.4 atm) (21% O2) - 1 atm] [10 m/atm] [6.66 atm - 1 atm] [10 m/atm] 56.6 mOther Relevant Lesson Plans from the Ocean ExplorationProgramCome on Down! galapagos/background/education/media/gal gr7 8 l1.pdf] (6 pages, 464k) (from the 2002Galapagos Rift Expedition)If your students aren’t up to the algebra, justfocus on the idea that the pressure of a mixtureof gases is divided among each of the gases inthe mixture, in proportion to the concentrationof each gas in the mixture.Focus: Ocean ExplorationThe Bridge ConnectionIn this activity, students will research the development and use of research vessels/vehicles usedfor deep ocean exploration; students will calculate the density of objects by determining themass and volume; students will construct a devicethat exhibits neutral – In the “Site Navigation” menuon the left, click on “Ocean Science Topics,” then“Human Activities,” then “Recreation” for links toresources about SCUBA divingThe “Me” ConnectionHave students write a brief essay describing howone or more of the gas laws might be directly relevant to their own lives.A Matter of Density mountains/background/edu/media/MTS04.density.pdf] (6 pages, 416k) (from the 2004 Mountainsin the Sea Expedition)Connections to Other SubjectsLife Science, MathematicsFocus: Temperature, density, and salinity in thedeep sea (Physical Science)AssessmentDiscussions and written responses (if assigned)provide opportunities for assessment.In this activity, students will be able to explainthe relationship among temperature, salinity, anddensity; and, given CTD (conductivity, temperature, and density) data, students will be able tocalculate density and construct density profilesof a water column. Students will also be able toexplain the concept of sigma-t, and explain howdensity differences may affect the distribution oforganisms in a deep-sea environment.Extensions1. Visit to keep up to date withthe latest 2007: Exploring the Inner Space ofthe Celebes Sea Expedition discoveries, and tofind out what researchers are learning aboutdeep fore reef communities.2. Visit the Newton’s Apple Teacher Guide

oceanexplorer.noaa.gov2007: Exploring the Inner Space of the Celebes Sea – Grades 7-8 (Physical Science)Focus: Gas lawsWho Has the Light? deepscope/background/edu/media/WhoHasLight.pdf] (PDF, 200Kb) (from the 2004Operation Deep Scope ivingocean/livingocean coral.html – Ocean Explorer photograph galleryHamner, W. M. 1975. Underwater observations ofblue-water plankton: Logistics, techniques,and safety procedures for divers at sea.Limnology and Oceanography 20:10451051; available online at 20/issue 6/1045.pdf.Focus: Bioluminescence in deep-sea organismsIn this activity, students compare and contrast chemiluminescence, bioluminescence, fluorescence,and phosphorescence. Students also explain atleast three ways in which the ability to producelight may be useful to deep-sea organisms andexplain how scientists may be able to use lightproducing processes in deep-sea organisms toobtain new observations of these rvalforms/ – ImageQuest 3-D Web site, featuring images ofnumerous marine organisms; all images arecopyrighted, but are still great to look html –“Buoyancy Basics” Web site from NOVAIt’s a Gas! Or Is It? fire/background/edu/media/rof05 gas.pdf](9 pages, 270Kb) (from the New ZealandAmerican Submarine Ring of Fire rplane/aboyle.html –Animated demonstration of Boyle’s Lawfrom NASA’s Glenn Research CenterFocus: Effects of temperature and pressure onsolubility and phase state (Physical ks/learnnet/classic exp.htm – TheRoyal Society of Chemistry’s “ClassicChemistry Experiments”In this lesson, students will be able to describe theeffect of temperature and pressure on solubilityof gases and solid materials; describe the effectof temperature and pressure on the phase stateof gases; and infer explanations for observedchemical phenomena around deep-sea volcanoesthat are consistent with principles of solubility andphase state.National Science Education StandardsContent Standard A: Science As Inquiry Abilities necessary to do scientific inquiry Understandings about scientific inquiryContent Standard B: Physical Science Properties & changes of properties in matterContent Standard F: Science in Personal and SocialPerspectives Personal health Science and technology in societyOther Links and ResourcesThe Web links below are provided for informational purposes only. Links outside of OceanExplorer have been checked at the time of thispage’s publication, but the linking sites maybecome outdated or non-operational over time.Ocean Literacy Essential Principles and FundamentalConceptsEssential Principle 1.The Earth has one big ocean with many features.Fundamental Concept h. Although the ocean islarge, it is finite and resources are limited. – Web site for NOAA’sOcean Exploration program

2007: Exploring the Inner Space of the Celebes Sea – Grades 7-8 (Physical Science)Focus: Gas lawsoceanexplorer.noaa.govcal modifications (such as changes to beaches,shores and rivers). In addition, humans haveremoved most of the large vertebrates from theocean.Fundamental Concept g. Everyone is responsiblefor caring for the ocean. The ocean sustains lifeon Earth and humans must live in ways that sustain the ocean. Individual and collective actionsare needed to effectively manage ocean resources for all.Essential Principle 5.The ocean supports a great diversity of life and ecosystems.Fundamental Concept c. Some major groups arefound exclusively in the ocean. The diversity ofmajor groups of organisms is much greater in theocean than on land.Fundamental Concept d. Ocean biology providesmany unique examples of life cycles, adaptationsand important relationships among organisms(such as symbiosis, predator-prey dynamics andenergy transfer) that do not occur on land.Fundamental Concept e. The ocean is threedimensional, offering vast living space anddiverse habitats from the surface through thewater column to the seafloor. Most of the livingspace on Earth is in the ocean.Fundamental Concept f. Ocean habitats aredefined by environmental factors. Due to interactions of abiotic factors such as salinity, temperature, oxygen, pH, light, nutrients, pressure, substrate and circulation, ocean life is not evenly distributed temporally or spatially, i.e., it is “patchy.”Some regions of the ocean support more diverseand abundant life than anywhere on Earth, whilemuch of the ocean is considered a desert.Essential Principle 7.The ocean is largely unexplored.Fundamental Concept a. The ocean is the lastand largest unexplored place on Earth—less than5% of it has been explored. This is the greatfrontier for the next generation’s explorers andresearchers, where they will find great opportunities for inquiry and investigation.Fundamental Concept b. Understanding theocean is more than a matter of curiosity.Exploration, inquiry and study are required to better understand ocean systems and processes.Fundamental Concept c. Over the last 40 years,use of ocean resources has increased significantly, therefore the future sustainability of oceanresources depends on our understanding of thoseresources and their potential and limitations.Fundamental Concept d. New technologies,sensors and tools are expanding our ability toexplore the ocean. Ocean scientists are relyingmore and more on satellites, drifters, buoys, subsea observatories and unmanned submersibles.Fundamental Concept f. Ocean exploration istruly interdisciplinary. It requires close collaboration among biologists, chemists, climatologists,computer programmers, engineers, geologists,meteorologists, and physicists, and new ways ofthinking.Essential Principle 6.The ocean and humans are inextricably interconnected.Fundamental Concept a. The ocean affects everyhuman life. It supplies freshwater (most raincomes from the ocean) and nearly all Earth’s oxygen. It moderates the Earth’s climate, influencesour weather, and affects human health.Fundamental Concept b. From the ocean weget foods, medicines, and mineral and energyresources. In addition, it provides jobs, supportsour nation’s economy, serves as a highway fortransportation of goods and people, and plays arole in national security.Fundamental Concept e. Humans affect the oceanin a variety of ways. Laws, regulations andresource management affect what is taken outand put into the ocean. Human development andactivity leads to pollution (such as point source,non-point source, and noise pollution) and physi-Send Us Your FeedbackWe value your feedback on this lesson.Please send your comments

oceanexplorer.noaa.gov2007: Exploring the Inner Space of the Celebes Sea – Grades 7-8 (Physical Science)Focus: Gas lawsFor More InformationPaula Keener-Chavis, Director, Education ProgramsNOAA Ocean Exploration ProgramHollings Marine Laboratory331 Fort Johnson Road, Charleston SC 29412843.762.8818843.762.8737 his lesson plan was produced by Mel Goodwin,PhD, The Harmony Project, Charleston, SCfor the National Oceanic and AtmosphericAdministration. If reproducing this lesson, pleasecite NOAA as the source, and provide the following URL:

ciples stated in Boyle’s Law, Charles’ Law, Gay-Lussac’s Law, Henry’s Law, and Dalton’s Law. Students will be able to explain the application of Boyle’s Law, Charles’ Law, Gay-Lussac’s Law, Henry’s Law, and Dalton’s Law to observations or events related to SCUBA diving. MateriaLs None audio/visuaL MateriaLs None teachinG tiMe

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