ctiit 1 deacher edition physicsquest 212 · 2013-03-27 · regular bubbles will float to the top of...

Teacher Edition

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PhysicsQuest2012

Activity

PhysicsQuest 2012 Teacher Edition

Non-Newtonian Extension: Activity 1Moon Blob GelSaftey: Do not put any Chemicals near your mouth, eyes, ears or nose.

The Gravity-Goo powder can be a choking hazard.

Materials:

• Two 500mL beakers

• Steve Spangle Gravity-Goo

• Water

• Food coloring

Instructions:

1. Add 480mL of tap water to one of the beakers

2. Add about 1 teaspoon of the Gravity-Goo powder to the second beaker

3. Mix the two beakers together by pour the water back and forth between the two

a. Do this is a rapid manor so that clumps don’t from in the Gel

4. Mix the beakers for about 4 min

5. With all of the Gel in one beaker, let it sit for about 30min or longer

a. The longer the Gel sits the smoother pouring it will be

6. Hold the beaker with the Gel above the empty beaker and start to pour a thick stream of the Gel into the lower beaker

a. The farther the two beakers are apart the better the effect works

7. As the stream begins to fall don’t move the upper beaker and allow the Gel to pull itself out of the beaker

Discussion:

The Gravity Goo is a polymer (large macro molecule) that is designed to both absorb water rapidly and link molecules into a long chain. When water is added to the powder it quickly get absorbed and forms a gel. Mixing the powder and water not only ensures that the powder will be equally dissolved but it also begins to tangle the long strands of mole-cules that make up the gel. Because the molecules become tangled, they pull on each other to try to stay together. By pouring the gel out of the upper beaker, the falling molecule chains of gel pull the connecting molecules of gel that are still in the beaker. The result is that the long chains of molecules are linked together strong enough to pull most of the gel up and out of the beaker. The liquid appears to defy gravity ad flow up hill in order to leave the top beaker.

Extra resources and Bibliography:

• http://www.stevespanglerscience.com/content/experiment/gravi-goo• http://www.stevespanglerscience.com/product/gravi-goo-jar

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PhysicsQuest2012

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Non-Newtonian Extension: Activity 2Comparing the Viscosity of FluidsCreate a Viscometer to measure a fluids viscosity

Safety: Be careful when handling the scissors while cutting the bottom of the dish detergent bottle. If the bottom is already cut off it may have some sharp edges.

When testing different fluids, be sure to follow the safety instructions for the fluids that you use.

Materials:

• Scissors

• Clear plastic dish detergent bottle with a pull top

• Marking pen

• Ruler

• Modeling clay

• Glass jar with a mouth slightly smaller than the upper part of the detergent bottle

• Water

• Dish detergent

• Vinegar

• Corn Oil

• Timer

Discussion:

In this activity we are going to measure the viscosity of different fluids. Viscosity is simply how much a fluid resists mov-ing. The slower a fluid flows through the detergent bottle cap the higher that fluid’s viscosity is. *Viscosity is a property of fluids, which means that it will always the same no matter the size of the opening to come out of.

By comparing the amount of time it took a fluid to go through the cap to the time it took water to go through the cap, the students can estimate the viscosity of the fluid. Flow rate and viscosity are not a linear relation; instead to get an estimate on how viscosities relate you need to compare the average squared times for the fluid flow.

Acceptable difference from water

Vinegar 1-5Corn Oil 60-80Dish Soap >5000

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Non-Newtonian Extension Activities

Suggested Resources and Bibliography:

• http://www.education.com/science-fair/article/viscosity/

• http://www.nist.gov/data/PDFfiles/jpcrd121.pdf

• http://www.sciencedirect.com/science/article/pii/0002870365900700

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Non-Newtonian Extension: Activity 3Anti-BubblesCreate bubbles that hover in water

Safety: Follow the safety label on the dish soap bottle for handling the dish soap

Materials:

• Water

• Large clear jar

• Water dropper

• Dishwashing detergent

• Artificial Sweetener

Discussion:

Regular bubbles will float to the top of the water or even hover in the air. This is because regular bubbles are a pocket of air that is surrounded by a thin layer of water. While Anti-Bubbles may look like normal bubbles, they behave much dif-ferently. Anti-Bubbles only form under water and then hover in the water until they pop. They do not rapidly rise to the surface like regular bubbles. This is because Anti-Bubbles are a pocket of water that is surrounded by a very thin layer of air. The air prevents the water pocket from dispersing into its surroundings. The hovering effect is due to the fact that be-cause both the Anti-Bubble and surrounding water are made of the same material and therefore have the same density.

http://amasci.com/amateur/antibub/anti7.gif

The reason that Anti-Bubbles are able to be made in soapy water is that the soap lessens the surface tension of the wa-ter making it easier for air to be pushing down into the liquid. Once the jet of water and air are in the jar, the jet’s sides begin to collapse due to the increased pressure. This causes the thin air surface to form the anti-bubbles.

Here are some more tips for working with Anti-Bubbles:

Anti-Bubbles are sensitive to electric charges; the water inside of the bubble will become polarized in an electric field and become attracted to the water below it. This causes the Anti-Bubble to pop once it collides with the surface of the water. This can be demonstrated by rubbing a plastic comb through your hair and the waving it near the surface of the water that has Anti-Bubble droplets on it. The comb will be charged and cause the droplets to pop. While this is a cool demonstration, this effect can cause problems when trying to make Anti-Bubbles. An electric charge can build up on your

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hand or clothing and then pop any potential Anti-Bubbles. Simply touch the metal faucet of the sink or some other metal object to remove any charge from your hand and clothing.

Also you can adjust how your Anti-Bubble hovers in water by using more sugar. If you put more sugar in the water drop-per, the dropper’s water will be denser than the jar water and the Anti-Bubbles will sink more. If your Anti-Bubbles sink too much, add sugar to the jar so the jar water’s density will increase causing the Anti-Bubbles to rise more.

Suggested sources and Bibliography:

• http://amasci.com/amateur/antibub/antibub1.html

• http://physicsworld.com/cws/article/news/2004/jan/06/the-life-and-death-of-antibubbles

• http://chemistry.about.com/od/bubbles/a/Antibubbles.htm

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Student Edition

1PhysicsQuest 2012 Student Edition

Activity

PhysicsQuest2012

Non-Newtonian Extension: Activity 1Moon Blob GelSafety: Do not put any Chemicals near your mouth, eyes, ears or nose” “The Gravity-Goo powder can be a choking hazard

Materials:


• Steve Spangle Gravity-Goo

• Water

• Food coloring

Instructions:

1. Add 480mL of tap water to one of the beakers

2. Add about 1 teaspoon of the Gravity-Goo powder to the second beaker

3. Mix the two beakers together by pour the water back and forth between the two

a. Do this is a rapid manor so that clumps don’t from in the Gel

4. Mix the beakers for about 4 min

5. With all of the Gel in one beaker, let it sit for about 30min or longer

a. The longer the Gel sits the smoother pouring it will be

6. Hold the beaker with the Gel above the empty beaker and start to pour a thick stream of the Gel into the lower beaker

a. The farther the two beakers are apart the better the effect works

7. As the stream begins to fall don’t move the upper beaker and allow the Gel to pull itself out of the beaker

Discussion Questions:

1. What is causing the gel to flow up hill and out of the top beaker?

2. Is this different from the siphoning Demo that is also provided in another section?


• http://www.stevespanglerscience.com/content/experiment/gravi-goo

• http://www.stevespanglerscience.com/product/gravi-goo-jar

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PhysicsQuest2012

Non-Newtonian Extension: Activity 2Comparing the Viscosity of FluidsCreate a Viscometer to measure a fluid’s viscosity

Safety:

Be careful when handling the scissors while cutting the bottom of the dish detergent bottle. If the bottom is already cut off it may have some sharp edges.

When testing different fluids be sure to follow the safety instructions for the fluids that you use.

Materials:

• Scissors

• Clear plastic dish soap bottle with a pull top

• Marking pen

• Ruler

• Modeling clay

• Glass jar with a mouth slightly smaller than the upper part of the detergent bottle

• Water

• Dish Soap

• Vinegar

• Corn Oil

• Timer

Set up:

1. Cut off the bottom of the detergent bottle.

2. Hold the bottle upside down. With the marking pen, make two straight lines, one about 2.5 cm below the cut-off bottom and the second 10 cm below the first line.

3. Label the first line “Start” and the second line “Stop.”

4. Place a ring of clay around the top edge of the jar’s mouth.

5. Close the pull top, and stand the bottle upside down inside the jar. Mold the clay ring so that the bottle stands upright, but do not secure the bottle with the clay.

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PhysicsQuest 2012 Student Edition


http://01.edu-cdn.com/files/static/wiley/9780471467199/VISCOSITY_01.GIF

Instructions:

1. Fill the bottle to about 1.5 cm above the start line with tap water.

2. Open the bottle top and place the bottle back on top of the jar.

3. Start the timer when the water level reaches the start line.

4. Stop the timer when the water level reaches the stop line.

5. Record the time.

6. Do three trials and record each trial’s time.

7. Calculate the average time for water.

8. Enter the average time value in the appropriate space in the chart below

9. Rinse the bottle and then repeat steps for the other fluids you have to test.

Average Time (tave)

Average Time Squared (t2

ave)Difference from water

(t2ave-t

2water)

Viscosity(t2

ave-t2

water+1)

Water 0

Vinegar

Corn Oil

Dish Soap

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• Which fluid took the longest to flow out of the bottle?

• How does the time it took a fluid to flow out of the bottle relate to the fluids viscosity?

• If you were to double the opening the fluid came out of how would the viscosity of the fluid change?

• What is viscosity a measurement of?

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Activity

PhysicsQuest2012

Non-Newtonian Extension: Activity 3Anti-BubblesCreate bubbles that hover in water

Safety:

Follow the safety label on the dish soap bottle for handling the dish soap

Materials:

• Water

• Large clear jar

• Water dropper

• Dishwashing detergent

• Artificial sweetener

Set up:

1. Add dishwashing detergent to cover the bottom of the jar about 1/6 in thick.

2. Fill the jar with about 300mL (1.25 cups) of water

3. Make sure that the dishwashing detergent is well mixed in the water.

4. Try to remove or push the bubbles off to the side so you have a clear water surface

5. Add 5 packs of Sweet ‘n Low Coffee sweetener to the jar.

6. Fill the water dropper with some of the soapy water from the jar.

7. Add about half of a Sweet ‘n Low pack to the dropper

Instructions:

1. Hold the water dropper near the surface of the water at 45o angle

2. Squeeze the dropper with a pulsation rhythm

3. With practice, you should be able to make bubbles that range 1/8 of an inch to ½ of an inch in diameter.

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• What makes up an Anti-Bubble?

• Why does the Anti-Bubble hover in the jar?

• What do you think would make the Anti-Bubble sink faster? rise faster?

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Turbulent Flow Extension: Activity 1Air FlowSee the direction that air takes as it flows around an object

Safety: The pins/needles are sharp so be careful to not poke yourself or other with them

Materials:

• Large cardboard surface

• 20-30 needles

o If you don’t have needles you can make the “flag poles” out if bent paper clips

• Paper

• Hair dryer

• Marker

• Scissors

• Circular obstruction

• Semi circle obstruction

• Straight obstruction

Discussion:

The flow of air around objects is a very important thing to study. Whether is building a community and houses to survive a tornado or designing the wings of an airplane, the applications of studying the movements of air are everywhere. This demo allows students to see the different air patterns around a curved surface and a flat surface. As air flows around a curved surface the air bends around and follows the direction of the curve. This called the Coanda Effect. This effect may be most noticeable when rotating the semi circular obstruction. The flags behind the obstruction will point away from the curved side, indicating that air follows the curve of the object. This is the same effect that causes air to flow along an airplane wing.

Additional References and Bibliography:

• http://www.daviddarling.info/childrens_encyclopedia/flight_Chapter1.html

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Turbulent Flow Extension Activities1

Figure 1

Figure 2

Figure 3

Pictures of setup:

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Turbulent Flow Extension: Activity 2SiphoningMaterials:


• Clear rubber hose

• Water

Instructions:

1. Position the two beakers so that one is on an elevated platform above the other

2. Add 400mL of tap water to the beaker that’s on the platform

3. Put the rubber hose into the beakers to from a pathway for the water to flow in

4. Suck on the end of the tube that is not in the water filled beaker in order to fill the hose with water.

a. Make sure the beaker end of the hose stays higher than the side of the hose you are sucking on

5. Once the hose is full of water, stop applying the suction and let the water fallout of the hose into the lower bea-ker

6. The water should continue to flow through the hose until all of the water in the top beaker has been transferred to the lower beaker

Discussion:

The siphoning effect can be explained using Bernoulli’s principle. Water will always want to flow from a point of high pressure to a point of low pressure. When you suck on the one end of the hose you are decreasing the pressure in the hose. The Water pressure in the hose is less than the water pressure in the beaker. As long as the hose is upright and the suction is applied the water will stay in the hose. Once you turn the hose so that the end you were sucking on is now in the lower beaker the pressure is the hose changes. The lowest water pressure is now at the apex of the hose instead of where you where sucking, but the end if the hose you were sucking on is still at a lower pressure than the end of the hose that is in the upper beaker. Gravity then takes takes over and begins to pull the water out of the hose. Gravity pulls the water on either side if the hump in the hose downward yet the water continues to flow uphill, out of the top beaker and then down into the lower beaker. Because the water in the side of the hose that goes down to the lower beaker has a larger distance to fall until it hits water again the velocity of the water is greater than the velocity of the water that wants to fall back into the upper beaker. As the water leaves the hose and falls into the lower beaker, water from the rest of the hose moves in to take its place. Water from the upper beaker gets pulled into the hose because the water pressure in the hose is less than the water pressure in the beaker. As long as the end of the hose in the upper beaker is submerged in water, the siphoning effect will continue to work.


• http://www.youtube.com/watch?v=T_1fgJ_bXfI

• http://www.daviddarling.info/encyclopedia/S/siphon.html

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Turbulent Flow Extension: Activity 3Laminar FlowDemonstrate the stream line flow in fluids

Safety: Be careful to not get any of the liquids in your eye

Materials:

• 2 transparency sheets

• PVC Slip Reducer 2 x 11/2 ‘’ *

• PVC Reducer Bushing 2 x 1½ ‘’ *

• 8 or more Rubber O Rings

• Scotch tape

• Saran wrap

• Corn Oil

• Oil coloring dye

• Syringe

• Scissors

• Straw

*use PVC pipe fittings without screw grooves

How to build the inner Couette Cell cylinder:

1. Cut one transparency sheet into a 12x6’’ rectangle

2. Wrap the transparency sheet around the PVR Reducer Bushing to form a cylinder 6’’ tall

3. Secure the transparency sheet with scotch tape

a. Be sure to seal both the inside edges where the sheet over laps on itself to make it as smooth as possible

4. Cut an inch long piece off of a straw and attach it as a marker to the top of the cylinder

6 inches

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How to build the outer Couette Cell Cylinder:

1. Use Saran Wrap and scotch tape to cover the small end of the PVC Slip Reducer

2. Place 6 or more Rubber O Rings on the small end of the PVC Slip Reducer

a. Save two more for later

3. Cut the second transparency sheet into a 12x6½ rectangle

4. Wrap the transparency sheet around the large end of the PVC Slip Reducer to form a cylinder

a. Make sure the small end of the PVC Slip Reducer is facing the inside of the cylinder

5. Secure the transparency sheet with scotch tape and 2 Rubber O Rings

6. The inner cylinder should now be able to fit around the small end of the PVC Slip Reducer in the center of the outer cylinder

Making the outer cylinder water/oil proof may be the hardest task so add reinforcing O Rings and scotch tape as needed.

Instructions:

• Fill the outer cylinder with 3½ inch of corn oil

• Insert the inner cylinder

• Mix some dye and corn oil in a separate container

• Fill the syringe with the dyed corn oil

• Use the syringe to make a ball of dyed corn oil in-between the walls of the two cylinders

• Slowly and smoothly turn the inner cylinder 1-3 revolutions while holding the outer cylinder securely

• Slowly and smoothly turn the inner cylinder the same number of revolutions in the opposite direction

• You should see the dyed corn oil get mixed up and then reform into its original ball

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Discussion:

Laminar flow is also known as streamline flow. This type of flow occurs when a fluid flows in parallel layers, with no disruption between the layers. This is different form Turbulent flow, which is random chaotic flow of a fluid.

The oil that is closest to the rotating inner cylinder rotates faster than the oil closest to the outer cylinder. This causes the dyed oil not to mix but “stretch out” in the cylinder. When you are done turning the inner cylinder the first direction the dye streams appear to be smeared out but they are actually individual streams layered around each other. By rotating the inner cylinder the opposite direction you are “re-collapsing” the stream exactly the way that they were “stretched out”. When you are done with the second rotation the streams of oil are back in the same location as they were in the beginning.

The reason corn oil is used is because it is a fluid with a high viscosity. A high viscosity fluid resists movement more than a low viscosity fluid. This is important because you need an easily controllable fluid for this demo. The dispersion rate is longer in a high viscosity fluid. We want to eliminate as much dispersion as possible to focus only on the movement of the fluid.

Bibliography:

• http://en.wikipedia.org/wiki/Laminar_flow

• http://www.youtube.com/watch?v=p08_KlTKP50

Student Edition


Activity

PhysicsQuest2012

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Turbulent Flow Extension: Activity 1Air FlowSee the direction that air takes as it flows around an object

Safety:

The pins/needles are sharp so be careful to not poke yourself or other with them

Materials:

• Large cardboard surface

• 20-30 needles

o If you don’t have needles you can make the “flag poles” out if bent paper clips

• Paper

• Hair dryer

• Marker

• Scissors

• Circular obstruction

• Semi circle obstruction

• Straight obstruction

Instruction:

1. Draw a line with the marker down the center of large cardboard surface

2. Push the flags in so that they cover most of the card board surface

a. They should still be able to swing freely when you blow on them

3. Set up the circular obstructions so that it is centered with the line on cardboard (figure 1)

4. Turn on the hair dryer and aim it at the obstruction along the line drawn on the cardboard

5. Let the flags swing into position and not their direction

6. Set up the straight obstruction so that o creates a wall in from of the flags (figure 2)

7. Turn on the hair dryer to view the air flow

8. Set up the semi circle obstruction so that the curved end faces the hair dryer

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9. Use the hair dryer to view the air flow

10. Don’t turn the hair dryer off but slowly rotate the obstruction 360o and watch how the air flow pattern changes (figure 3)


1. How does the flag pattern compare between different shaped obstacles?

2. Does wind interact with a flat surface differently than with a curved surface? How?

3. What happened to the flag pattern as the semi circle obstruction was rotated?

Additional References and Bibliography:

• http://www.daviddarling.info/childrens_encyclopedia/flight_Chapter1.html

Pictures of setup:

Figure 1

Figure 2

Figure 3

Student Edition


Activity

PhysicsQuest2012

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Turbulent Flow Extension: Activity 2SiphoningMaterials:


• Clear rubber hose

• Water

Instructions:

1. Position the two beakers so that one is on an elevated platform above the other

2. Add 400mL of tap water to the beaker that’s on the platform

3. Put the rubber hose into the beakers to from a pathway for the water to flow in

4. Suck on the end of the tube that is not in the water filled beaker in order to fill the hose with water.

a. Make sure the beaker end of the hose stays higher than the side of the hose you are sucking on

5. Once the hose is full of water, stop applying the suction and let the water fallout of the hose into the lower bea-ker

6. The water should continue to flow through the hose until all of the water in the top beaker has been transferred to the lower beaker


1. Which point in the hose has the lowest pressure?

2. What pulls the water out of the hose and into the lower beaker?

3. Is the water moving fast in the upper beaker or in the hose?


• http://www.youtube.com/watch?v=T_1fgJ_bXfI

• http://www.daviddarling.info/encyclopedia/S/siphon.html

https://encryptedtbn3.google.com/images?q=tbn:ANd9GcRYARdFKU3L pDLpFl_01s32WwAAvXrSLYbZv7jS_5LqqE0lwxxiFA

Student Edition


Activity

PhysicsQuest2012

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Turbulent Flow Extension: Activity 3Laminar FlowDemonstrate the stream line flow in fluids

Safety: Be careful to not get any of the liquids in your eyes

Materials:

• 2 transparency sheets

• PVC Slip Reducer 2 x 11/2 ‘’ *

• PVC Reducer Bushing 2 x 1½ ‘’ *

• 8 or more Rubber O Rings

• Scotch tape

• Saran wrap

• Corn Oil

• Oil coloring dye

• Syringe

• Scissors

• Straw

*use PVC pipe fittings without screw grooves

Instructions:

1. Fill the outer cylinder with 3½ inch of corn oil

2. Insert the inner cylinder

3. Mix some dye and corn oil in a separate container

4. Fill the syringe with the dyed corn oil

5. Use the syringe to make a ball of dyed corn oil in-between the walls of the two cylinders

6. Slowly and smoothly turn the inner cylinder 1-3 revolutions while holding the outer cylinder securely

7. Slowly and smoothly turn the inner cylinder the same number of revolutions in the opposite direction

8. You should see the dyed corn oil get mixed up and then reform into its original ball

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• What happens to the dye when the inner cylinder is first rotated?

• What happens to the dye when the cylinder is rotated the second time?

• Why doesn’t the dye get mixed into the surrounding oil?

• How is laminar flow different than Turbulent flow?

Bibliography:

• http://en.wikipedia.org/wiki/Laminar_flow

• http://www.youtube.com/watch?v=p08_KlTKP50

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PhysicsQuest2012

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1

Brazil Nut Extension Activity 1Shock absorbent sandMaterials:

• Sand

• Paper towel tube

• Tissues

• Dowel

o Any solid cylinder that is heavy enough to break the tissue and small enough to fir into the paper towel tube

• Ruler

Discussion:

Many small animals dig burros in the sand to live in. These small sand caves are very resistant collapsing. This is because sand is a good absorber of shock. Shock is the quick application of pressure on an object. Normally, when the dowel is dropped onto the tissue the tissue rips. However, by adding sand onto of the tissue allows the energy from the dowel to the dispersed, thus preventing the tissue from ripping. Sand is able to disperse the energy because it is composed of small granules. These granules, although solid, are free to move around in their environment. When the dowel hits the sand the granules at the top of the pile are sprayed upward while the other granules are pressed against the side of the tube. The moving of the granule also creates small amount of friction which converts energy into heat. All of these dissi-pate the energy of the falling dowel. The more sand that there is in the tube the more granules can press against the side of the tube. As long as enough sand is in the tube to dissipate the shock energy the tissue will not rip. Once there is too little sand the dowel is able to transfer enough energy to the tissue to cause it to rip.

You can also create more demos with this by replacing the sand with some other material and then test to see how much of that other object is needed to dissipate enough energy.

Warning, if there is sand in the tube and he tissue rips all of the sand will pour out of the tube. You may want to do this demo over a container to catch the falling sand once the tissue rips.

Bibliography and extra sources:

• http://www.archbold-station.org/discoveringflscrub/unit1/proj1a1.html

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Brazil Nut Extension Activity 2Angle of ReposeGranular Stability

Materials:

• Plate/Tray

• Water

• Sand

• Small pebbles

• Large pebbles

• Small round balls

• Protractor

• Ruler

Instructions:

1. Pour a stream of sand into a pile on the plate/tray

2. Be sure to make the pile large enough to measure an angle from

3. Place the rule along the pile walls so you have a straight line to measure the pile’s angle

4. Use the protractor to measure the angle that the pile walls makes

5. Repeat with the other granular materials you have.

You can also compare how water affects the angle of repose for materials

1. Add water to the sand until it is saturated

2. Pour the saturated sand into a pile

3. Measure the angle of repose just like before

Discussion:

The Angle of Repose is the maximum angle of stability for a granular material. A material cannot form a pile with walls steeper than the angle because the granules will slide down until they reach the bottom. The Angle of Repose is depen-dent on the angularity of the granule and the ability for the granules to link together. The rounder the granule the shal-lower the Angle of Repose will be. Water also decreases the Angle of Repose because the water prevents the granules from “grabbing” onto each other so they have less support.

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Turbulent Flow Extension Activities

Bibliography:

• http://serc.carleton.edu/quantskills/activities/Angleofrepose.html

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Brazil Nut Extension Activity 3Density ball sortingSafety: Small marbles can be a choking hazard

Materials:

• Lots of small marbles

• 4-5 heavy metal ball

• 4-5 marble sized plastic balls

• circular container with a lip

o A solid Frisbee works well

Discussion:

This is an experiment that is being developed at the University of Bayreuth in Germany1, it is meant to help physicists study the causes of the Brazil Nut Effect better. The Brazil Nut Effect is demonstrated when a large grain can be shaken to the top of a pile of smaller grains. Scientists have also found a reverse Brazil Nut Effect, when a larger grain can sink to the bottom of a small grain pile but only when that large grain is less dense than the surrounding grain. More dense grains still rise to the top. This is a puzzle to scientists because normally the more dense materials sink to the bottom and else dense materials end up on top. In this activity you can explore both the Brazil Nut Effect and its reverse. The heavier, more dense, balls gather in the center of the disk while the lighter, less dense, balls travel toward the outside of the disk. This is an opportunity for the students to brain storm and hypothesis about what causes this motion of the balls.

Bibliography and extra recourses:

• http://news.sciencemag.org/sciencenow/2005/07/08-02.html

• http://large.stanford.edu/courses/2007/ph210/spector2/

Picture:

Student Edition


Activity

PhysicsQuest2012

1

Brazil Nut Extension Activity 1Shock absorbent sandMaterials:

• Sand

• Paper towel tube

• Tissues

• Dowel

o Any solid cylinder that is heavy enough to break the tissue and small enough to fir into the paper towel tube

• Ruler

Instructions:

1. Take a single issue and rubber band it to cover one end of the paper towel tube

2. Fill the tube ¾ with sand

3. Measure the length of the tube

4. Measure the distance from the top of the sand to the top of the tube

5. Find the difference in height to know how deep the sand is

6. Predict what the minimum amount of sand is necessary to keep the tissue from breaking

7. Hold the dowel at the top of the tube and then drop in into the sand

8. Record whether or not the tissue on the bottom breaks

9. If the tissue does not break empty some of the sand out of the tube and try again

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Brazil Nut Extension Activities

Trial # Height of tube (A)

Distance from sand to top of tube (B)

Depth of sand (A-B)

Did the tissue break?

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• Why does the tissue not break when there is sand in the tube even though the sand puts extra weight on the tissue?

• In what ways does the sand dissipate the energy from the falling dowel?

Bibliography and extra sources:

• http://www.archbold-station.org/discoveringflscrub/unit1/proj1a1.html

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Student Edition


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PhysicsQuest2012

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Brazil Nut Extension Activity 2Angle of ReposeGranular Stability

Materials:

• Plate/Tray

• Water

• Sand

• Small pebbles

• Large pebbles

• Protractor

• Ruler

Instructions:

1. Pour a stream of sand into a pile on the plate/tray

2. Be sure to make the pile large enough to measure an angle from

3. Place the rule along the pile walls so you have a straight line to measure the pile’s angle

4. Use the protractor to measure the angle that the pile walls makes

5. Repeat with the other granular materials you have.

You can also compare how water affects the angle of repose for materials

1. Add water to the sand until it is saturated

2. Pour the saturated sand into a pile

3. Measure the angle of repose just like before

Discussion questions:

• Which material had the steepest angle?

• How did the size of the granules affect the angle?

• How did adding water affect the angle of repose for sand?

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Activity


Brazil Nut Extension Activities2

Bibliography:

• http://serc.carleton.edu/quantskills/activities/Angleofrepose.html

Picture of Experiment:

Brazil Nut Extension Activity 2

Angle of Repose Granular Stability

Materials: • Plate/Tray • Water • Sand • Small pebbles • Large pebbles • Protractor • Ruler

Instructions:

1. Pour a stream of sand into a pile on the plate/tray 2. Be sure to make the pile large enough to measure an angle from 3. Place the rule along the pile walls so you have a straight line to measure the pile’s angle 4. Use the protractor to measure the angle that the pile walls makes 5. Repeat with the other granular materials you have.

You can also compare how water affects the angle of repose for materials 1. Add water to the sand until it is saturated 2. Pour the saturated sand into a pile 3. Measure the angle of repose just like before

Discussion questions: • Which material had the steepest angle? • How did the size of the granules affect the angle? • How did adding water affect the angle of repose for sand?

Bibliography: http://serc.carleton.edu/quantskills/activities/Angleofrepose.html Picture of Experiment:

Matthew Goszewski 7/23/12 10:35 AMComment [1]: Picture of a ruler measuring a pile of sand on a plate/dish

Student Edition


Activity

PhysicsQuest2012

Brazil Nut Extension Activity 3Density ball sortingSafety: Small marbles can be a choking hazard

Materials:

• Lots of small marbles

• 4-5 metal ball bearings

• 4-5 marble sized bouncy balls

• circular container with a lip

o Solid Frisbee works well

Instructions:

1. Fill the circular container with the marbles

2. Place the bouncy balls in the center of the container

3. Place the ball bearings around the edge

4. There should be enough room for you to shake the container and have all of the balls move around but at least 90% of the container should be filled with balls.

5. Shake the container in a circular motion, like gold mining


• What happens to the balls as you shake the container?

• What is the difference between the balls that move to the edge of the container to the balls the move to the center of the container?

• What could be some reasons this happens?

Bibliography and extra recourses:

• http://news.sciencemag.org/sciencenow/2005/07/08-02.html

• http://large.stanford.edu/courses/2007/ph210/spector2/

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Teacher Edition

1

PhysicsQuest2012

Activity


1

Vortices/Convection Extension Activity 1Coanda Effect 1Air pressure difference for moving air

Safety: Follow operating safety instructions for the hair dryer you use

Materials:

• Hair dryer

• Ping-Pong ball

Instructions:

1. Plug in the hair dryer

2. Turn hair dryer to the high setting

3. Point the hair dryer vertically

4. Place Ping-pong ball into the air stream

5. As the ball hovers tilt the hair dryer at different angles and watch the ball stay in the air stream

Discussion:

This demonstration is often confused to be the result of the Bernoulli Effect but it is actually the Coanda Effect. The Coanda Effect is seen where a moving fluid is attracted to a nearby surface. As the air bends around the ball it experienc-es a centripetal force pulling it toward the center of the ball. According to Newton 3rd law, because there is a force acting to curve the air stream down here is also a force acting on the ball in an equal and opposite direction. This means that this pushes the ball up into the air stream.

This is also the effect that is the most responsible for keeping aircraft in the air. The top of an aircraft wing is curved so that the air will bend over the wing. As the air is curved downward the wing experienced a force upward, creating the lifted needed to fly the plane.

Bibliography:

• http://www.youtube.com/watch?v=9YaUC8W0P7c

• http://en.wikipedia.org/wiki/Coand%C4%83_effect

• https://encrypted-tbn1.google.com/images?q=tbn:ANd9GcQPx7TYW-vEfr--0P_eV2DeWnqK4iWDjIAaycP_Cn9m6aySKZgX

Teacher Edition

2

PhysicsQuest2012

Activity


1b

Vortices/Convection Extension Activity 1bCoanda Effect2 – lift Air pressure difference for moving air


Materials:

• Hair dryer

• Ping-Pong ball

• Large funnel

Instructions:

1. Attach the large funnel to the front of hair dryer so that the air flows from the small end to the large end



4. Place Ping-Pong ball into the funnel

5. Try to blow to Ping-Pong ball out of the funnel

6. With the Ping-Pong ball still in the funnel turn the hair dryer upside down

7. The ball does not fall out of the funnel

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Activity


Vortices/Convection Extension Activities1b

Discussion:

This demonstration is often confused to be the result of the Bernoulli Effect but it is actually the Coanda Effect. The Coanda Effect is seen where a moving fluid is attracted to a nearby surface. As the air bends around the ball it expe-riences a centripetal force pulling it toward the center of the ball. According to Newton 3rd law, because there is a force acting to curve the air stream down here is also a force acting on the ball in an equal and opposite direction. This means that if the air stream is point up the air rushes around the ball it pulls the ball down, into the airflow. Even if you do the experiment upside down the ball will not fall out of the funnel.

Bibliography:

• http://www.youtube.com/watch?v=wuAUJPUupfE

• http://mitchellscience.com/bernoulli_principle_animation

• http://hyperphysics.phy-astr.gsu.edu/hbase/pber.html

Teacher Edition

4

PhysicsQuest2012

Activity


2

Vortices/Convection Extension Activity 2Spool LiftAir pressure difference for moving air

Safety: Be careful when using the needle to not poke yourself or someone else

Materials:

• Spool

• Index card

• Sewing needle

Instructions:

1. Poke the sewing needle through the middle of the index card

2. Place the index card on one end of eth spool so that the sewing needle goes through the spool’s center hole.

3. Blow through the opposite side of the hole to try to make the index card fall off

Discussion:

This demo is possible thanks to inertia. Inertia is the principle of Newton’s 1st law, an object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force. As the air is blown through the small hole in the spool it is gaining momentum. When the air leaves the small hole and encounters the index card it begins to radiate out away from the small hole. Because of the air’s inertia the radial momentum of the air is also conserved. This means that as the air expands as a disk when leaving the small spool hole. The farther from the hole the larger the disk becomes. As the disk of air expands it becomes less dense. The less dense air has less pressure than the air underneath the index card. This pressure difference holds the index card up against the spool.

Bibliography:

• http://www.seykota.com/rm/spool_card/spool_card.htm

Teacher Edition

5

PhysicsQuest2012

Activity


Vortices/Convection Extension Activity 3Cold Lava LampSafety: Be careful to not spill when using liquids

Materials:

• Clear bottle /jar

• Water

• Corn Oil

• Food Coloring

• Alka-Seltzer tablets

Discussion:

A Lava Lamp is a great way to show students the combination of Buoyancy, Density, Convection, and Fluid Drag. Buoyan-cy is the force the fluid exerts to lift an up towards its surface. Density is a property of a material based on its mass and volume. Convection is the collective motion of particles within a fluid. Fluid Drag is the force that acts against an object motion in a fluid. A traditional Lava Lamp would use heat to create convection. When the water would be heated up it would begin to expand. This expansion decreases the density of the water which in turn causes it to rise through the not denser Oil. The water cools and becomes denser as it reaches the top. However, this Lava Lamp utilized the buoyant force of CO2 instead of heat to create a convection current.

Inside of the jar/bottle are two liquids that have different densities and don’t combine. Water is denser that the Oil so it will sink to the bottom. Oil is both less dense than water and is composed of mostly fats, which are hydrophobic and repel water. This means that the Oil floats on top of the water. The different density properties of the two fluids allow the convection current to form, while the different compositions of the fluids keep them from combining.

When the food coloring is dropped into the Lava Lamp to color the water, it doesn’t disperse into the Oil because the food coloring is water based which means the Corn Oil will not nix with it. Once it hits the Water-Oil interface is dispers-es into the water.

The Alka-Seltzer tablet also only reacts with water. When it reacts with water it gives off Carbon Dioxide. The CO2 bub-bles form water droplets and then provide the buoyant force needed lift those droplets to the surface of the Oil. Once the Water+CO2 bubbles reach the surface the CO2 escapes but the water then sinks back down to the bottom. Fluid drag then takes over and slows the droplet as it falls through the Corn Oil. This causes the droplets to fall slower than is they were in air.

Suggested links and Bibliography:

• http://www.stevespanglerscience.com/experiment/bubbling-lava-lamp

• http://www.youtube.com/watch?v=WayviQkusxI

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Student Edition


Activity

PhysicsQuest2012

1a

Vortices/Convection Extension Activity 1aCoanda Effect 1 Air pressure difference for moving air


Materials:

• Hair dryer

• Ping-Pong ball

Instructions:

• Plug in the hair dryer

• Turn hair dryer to the high setting

• Point the hair dryer vertically

• Place Ping-pong ball into the air stream

• As the ball hovers tilt the hair dryer at different angles and watch the ball stay in the air stream


• What causes the ball to stay in the air stream?

• Why doesn’t the ball fall when the air stream is at an angle?

• Change the speed of the air that is coming out of the hair dryer. How does the high speed air flow’s maximum angle for hovering compare to the lower speed airflow’s maximum angle for hovering?

Bibliography:



• https://encrypted-tbn1.google.com/images?q=tbn:ANd9GcQPx7TYW-vEfr--0P_eV2DeWnqK4iWDjIAaycP_Cn9m6aySKZgX

Student Edition


Activity

PhysicsQuest2012

1b

Vortices/Convection Extension Activity 1bCoanda Effect 2 Air pressure difference for moving air


Materials:

• Hair dryer

• Ping-Pong ball

• Large funnel

Instructions:

1. Attach the large funnel to the front of hair dryer so that the air flows from the small end to the large end



4. Place Ping-Pong ball into the funnel

5. Try to blow to Ping-Pong ball out of the funnel

6. With the Ping-Pong ball still in the funnel turn the hair dryer upside down


• Why does the Ping-Pong ball not get blown out of the funnel even with the air blowing upwards?

• What happens when the hair dryer is turned upside down? Why?

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Activity


Vortices/Convection Extension Activities1b

Bibliography:



• http://t2.gstatic.com/images?q=tbn:ANd9GcTmMKm_0LyL9HJKn4aKnfnXa-lLvabAPeyZ_REsK6mFGYtCjmLh15BvjZIJSA

Student Edition


Activity

PhysicsQuest2012

2

Vortices/Convection Extension Activity 2Spool LiftAir pressure difference for moving air

Safety: Be careful when using the needle to not poke yourself or someone else

Materials:

• Spool

• Index card

• Sewing needle

Instructions:

1. Poke the sewing needle through the middle of the index card

2. Place the index card on one end of eth spool so that the sewing needle goes through the spool’s center hole.

3. Blow through the opposite side of the hole to try to make the index card fall off

4. Turn the spool and index card over so the that card is facing the floor

5. Hold the card in place until you blow through the spool

6. Once you start to blow through the spool let go of the index card and watch what happens

Discussion questions:

• Why does the card stick to the spool?

• What would you do to make the index card stick less to eth spool?

• What would you do to make the index card stick more to the spool?

Bibliography:

• http://www.seykota.com/rm/spool_card/spool_card.htm

Student Edition


Activity

PhysicsQuest2012

3

Vortices/Convection Extension Activity 3Cold Lava LampSafety: If a glass jar/bottle is used be careful to no drop it or it might shatter.

Materials:

• Clear bottle /jar

• Water

• Corn Oil

• Food Coloring

• Alka-Seltzer tablets

Instructions:

1. Fill the clear bottle/jar 1/4 full with water

2. Pour the Corn Oil into the jar until there is only slightly more than an inch of free space at the top

3. Let the Corn Oil and water separate

4. Add the food coloring to the jar/bottle and wait a couple minutes for it to mix with the water

5. Break up an Alka-Seltzer tablet and drop it into the jar/bottle


• Why do the Oil and Water not mix?

• Why does the food coloring not color the Oil?

• What causes the water to rise to the top of the Oil? What is this motion called?

• How would a heat driven Lava Lamp be different?

Suggested links and Bibliography:

• http://www.stevespanglerscience.com/experiment/bubbling-lava-lamp

• http://www.youtube.com/watch?v=WayviQkusxI

ctiit 1 deacher edition physicsquest 212 · 2013-03-27 · regular bubbles will float to the top of...

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