*
*

Back to teachers Home

Volcano Under the City

Classroom Activity

Learning objective | materials | background | Procedure | task Answer | links & publications | Standards

*

Print this Teacher"s guide (PDF, 6 pages)

Activity SummaryStudents will experiment with three various liquids to identify the loved one viscosity and flow price of every liquid.

You are watching: The property of flowing very quickly in a liquid

Learning ObjectivesStudents will certainly be able to:

compare and also measure the relative flow rates of various liquids.

state that different kinds of lava different in their viscosity.

understand that a lava"s viscosity influences how conveniently it flows.

*
three 25 ml test tubes25 ml each of water, cooking oil, and also light corn syrup5 ml every of water, cooking oil, and also light corn syrup in separate paper cupsmasking tapesmall metal file clips of identical size and also massstopwatch/timersmall timber block around 4 cm in heightnon-stick cookie paper or pan, at least 25 cm longruler or measure tape3 plastic spoonspaper towelsgraph papercalculator

BackgroundMagmais molten rock below Earth"s surface. Magma rises in volcano vents; as soon as itreaches the surface it is referred to as lava. The three common species oflava—basaltic, andesitic, and rhyolitic—contain various amountsof silica (SiO2) and also dissolved gases. They have actually differentviscosities based upon the quantity of silica castle contain. Low-silica lavas areless viscous and also travel much faster than higher-silica lavas, i m sorry are much more viscousand travel slower. Viscous lavas sometimes cool prior to they travel really far,which is why castle are often less hazardous. Once magma or lava cools andsolidifies, it creates igneous rock. (Basalt, andesite, and also rhyolite are alligneous rocks.) The adhering to chart lists typical lava species and your flowrates. Keep in mind that lava operation pass with a range of viscosities as they cooland solidify; as lava loses heat, that viscosity increases.

Lava Type

Silica Content

Viscosity

Approximate circulation Rate

basaltic

least

least

30-60km/hr

andesitic

inbetween

inbetween

10km/hr

rhyolitic

most

most

1km/hr

Mount Nyiragongo is a volcano in the autonomous Republic that the Congo, 18kilometers indigenous Goma close to the Rwandan border. The area bordering the mountainis very populated. The volcano has an extremely fluid basaltic lava with an unusuallylow silica content, which move quickly. Throughout the 1977 eruption, the initialspeed of the lava circulation was estimated at 100 kilometers per hour. WhenNyiragongo erupted in January 2002, more than 250,000 people were temporarilydisplaced as soon as the lava, flow at speeds of about 60 kilometers per hour,overran the town of Goma.

Key Terms

flow rate: established by distance/time.

lava: Magma that has actually erupted native a volcano and also flowed to the Earth"s surface ar or the s floor.

silica:A common mineral written of silicon and also oxygen. Silica makes up nearly 75percent the Earth"s crust.

tephra: Air loss material, such as ash, produced by a volcaniceruption.

viscosity: The resistance the a fluid"s (gas or liquid) flow on aparallel plane.

*

Prepare the check tubes and cups for each team prior to the experiment.Pour 25 milliliters of every liquid into separate test tubes. Make sure eachtube has the same amount of liquid.

Discuss the concept of viscosity through students. Allude out that viscosity isa fluid"s resistance come flow. The viscosity that lava differs relying on theamount that silica in each kind of lava. Talk about some possible reasons whyscientists might want to research lava viscosity.

Organize students right into teams and administer a collection of products to every team.Explain come students the the different liquids model different varieties of lava.Tell students that they will be trying out with how liquids different in theirviscosity and how fluid viscosity and also rate of flow are related.

before having students command the document clip dropping experiment, call themthat one means to check the viscosity of a fluid is come drop an object into theliquid and find exactly how long the takes the object to sink. Comment on buoyancy anddensity and also talk around why the same object must be supplied for every liquid.

Have students command the experiments follow to the accuse on theirhandouts. Try to have actually students collection up your ramps at about the very same angles (iframp angles are not the same, outcomes will it is in relative). When students havecompleted the activity, record average results for each college student team (for bothexperiments) top top the board. Comment on the experiments and results. What didstudents observe around the three liquids? What is the connection betweenviscosity and flow rate? deserve to students think of some instances of daily itemsin i m sorry viscosity plays an essential role? (Some item include car enginesthat need oil to operation well and also food items prefer syrup that need to pourreadily.)

As one extension, have actually students determine just how temperature affect theviscosity of a liquid. Cool the liquids by placing a jug containing the liquidin a refrigerator. Then ask students come repeat the activity to determinewhether cooling the fluid affects viscosity and also how conveniently the liquidmoves.

*

Theexperiment discover a relationship between viscosity and flow rate. Students"bar graphs need to reflect the reality that water is the least viscous the the threeliquids and flows the fastest, while corn syrup is the most viscous and also flowsthe slowest.

Sample file Clip Dropping Data*

Cornsyrup

Oil

Water

Trial1

30sec

>1Sample rate of flow Data*

Cornsyrup

Oil

Water

Trial1

3min. 10 sec

44sec

3sec

Trial2

2min. 56 sec

42sec

2sec

Trial3

3min. 4 sec.

43sec.

2sec

AverageResult

3min. 4 sec(184 seconds)

43sec

2.3sec

Distance

25cm

25cm

25cm

FlowRate(distance/time)

25cm/184 sec = .1 cm/sec

25cm/43 sec = .6 cm/sec

25cm/2.3 sec = 11 cm/sec

*rampresting on finish of timber block 3.8 cm high, flow distance = 25 cm

Student Handout Questions

Compare the family member viscosities the the liquids to the speeds with which theliquids moved during your ramp tests. Based on your data, exactly how does theviscosity the the liquid influence the rate at which the fluid flows? Moreviscous liquids circulation slower than much less viscous liquids.

Nyiragongo is said to have actually lava the flows "like water." based on yourinvestigation, explain the viscosity of the lava developed by Nyiragongo.Nyiragongo volcano lava is not an extremely viscous and also flows quickly.

How could the viscosity of lava from a volcanic eruption impact the outcomeof one evacuation? an ext people and animals might be at threat if the lava isless viscous and also flows more quickly.

*

Web Sites

NOVA—Volcano Under the Citywww.cg-tower.com/nova/volcanocityLearn whether volcanic eruptions have the right to be predicted, find what it was liketo film in a volcanic crater, check out Nyiragongo"s main features, and also readhistoric account of the few of the worst volcanic calamities of the past 400years.

Natural Hazardsearthobservatory.nasa.gov/NaturalHazards/natural_hazards_v2.php3?img_id=1608Describes the Nyiragongo volcano eruption that emerged January 17,2002.

Volcanoeswww.learner.org/exhibits/volcanoes/entry.htmlDiscusses volcanic eruptions and also includes details on lava circulation rate andviscosity.

Books

A Glorious method to Die: The Kamikaze Mission that the Battleship Yamato,April 1945by Russell Spur. Newmarket Press, 1981.Analyzes theYamato"s last days native Japanese and Americanperspectives.

Earthquakes and also Volcanoesby Fiona Watt. Usborne Ltd., 1994.Provides diagrams, illustrations, and also photographs to describe earthquakes andvolcanoes.

The Visual thesaurus of the Earthby Charles Wills, editor. Dorling Kindersley, 1993.Includes a section on different species of volcanoes and also how lock erupt.

Volcanoes and Earthquakesby Susanna van Rose. Dorling Kindersley, 1993.Presents a visual screen of volcanoes and also how castle occur.

*

The "Thick and Thin" task aligns through the following NationalScience education Standards (see books.nap.edu/html/nses).

Grades K-4Science typical DEarth and room ScienceChanges in Earth and also sky

Grades 5-8Science standard DEarth and space ScienceStructure of the planet system

Classroom activity Author

MargyKuntz has written and also edited educational products for 20 years. She hasauthored plenty of educational supplements, basal message materials, and tradebooks on science, math, and computers.

*
*

Volcano Under the City

*

Original broadcast:November 1, 2005

*
*
*
*
*
*
*
*
*

Major capital for NOVA is provided by Google and BP.

See more: How Many Minutes Are 100 Seconds Equals How Many Minutes Are 100 Seconds?

*

Additional capital is listed by the Howard Hughes clinical Institute, theCorporation for Public Broadcasting, and public television viewers.