September 2006
Naomi J. Marty
GK-12 Program
Concept:
Earth Science: Volcanoes
Materials:
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white vinegar
baking soda
volcano model
tissue paper
potato or cork stopper
plastic bottle
unflavored gelatin
250mL cups or bowls for volcano molds
red food coloring
light corn syrup
unflavored gelatin
small containers with a lid
pegboard (large enough to be held up by food tray edges), with 5mM holes
large trays
20-50mL syringe
standard airline tubing (aquarium)
mini airline tubing with connectors for standard airline tubing
60mL (cc) disposable syringes with Leur lock
plastic knife
State Standards:
(arkedu.state.ar.us)
ESS.8.6.4
Conduct investigations to identify the variables within volcanoes that cause
different types of eruptions
ESS.8.6.5
Diagram and explain how volcanoes work
ESS.8.6.6
Explain how volcanic activity relates to mountain formation
ESS.8.6.15
Investigate careers, scientists, and historical breakthroughs related to internal
forces that change the earth
Procedure
1. As the class is ready, perform a simple baking soda & vinegar volcanic
eruption from a volcano model. After the eruption, open the volcano
model, so that the class can see what is going on inside the volcano.
What to do
1. Put 7.5mL baking soda into a model with 150mL vinegar and food coloring. Watch the
eruption!
2. Using pictorial representations in a powerpoint presentation, present some
cool pictures of real volcanoes, how they are formed (and how they can
form mountains), and how they function. Show a slide about how
scientists and how they study volcanoes.
3. Do a demonstration of an explosive volcano, doing the same reaction, but
placing a cork over the vent hole, so that pressure has to build up and
make an explosion. Make sure to follow safety protocol.
What to do
1. Put 7.5mL baking soda in tissue paper and drop into a plastic bottle with 150mL vinegar,
immediately closing with cork. Step back, and watch the eruption!
4. Discuss what the cork represents in a real-life volcano (hardened magma in
vent hole).
5. Identify variables within volcanoes that cause different types of eruptions.
6. Do lava flow demonstration with Holt Science ‘How’s Your Lava Life?’ activity
(modified for group work).
Preparation
1. Prepare the gelatin for the volcano models by mixing 500mL of cool water with the
contents of four envelopes of unflavored gelatin in a 2L graduated cylinder. Stir for 2min.
Boil 1.5L of water. Add 1.5L of boiling water, and stir until the gelatin is dissolved. Pour
into cup molds. (This recipe makes enough for 8 250mL cups.) Refrigerate for at least 3
hours or overnight.
2. Prepare the “magma” in the small container by mixing just enough light corn syrup and
water with red food coloring to make a very dark liquid. Set aside.
What to do
1. Fill a large bowl about halfway with hot water. Remove the gelatin from the refrigerator,
and loosen it from the cups by dipping the cups briefly in the bowl of hot water.
2. Lay the pegboard on top of a food serving tray to collect drips.
3. Attach ~6” mini airline tubing to leur lock syringe. Using connectors, attach ~ 12”
standard airline tubing to mini airline tubing and weave it into the pegboard from the top
and back up through the bottom so that 2” or so of tubing is sticking up out of the
pegboard. Remove the plunger.
4. Fill the syringe with your prepared “magma.” Remove any air bubbles from the syringe
and tubing by holding the syringe upright and squirting out a small amount of the liquid.
Air tends to fracture the gelatin.
5. Unmold the gelatin by tipping the bowl over onto the center of the pegboard on top of the
tubing and lifting the bowl. Do this very carefully so that the gelatin cast won’t develop
cracks; a few small cracks are acceptable. The gelatin cast will spread and settle. It
should resemble a colorless to milky volcano.
6. Inject the red water very slowly, at a rate of about 20 ml/min. Have each student push
about 10mL through with the other students watching carefully.
7. Ask students to describe what they observed. (If the gelatin is fractured, the red dye will
flow out of the fractures. If there are no fractures, the dye should flow out equally in all
directions.)
8. Use a knife to slice open the volcano, and view the cross-section. Tell students that in
the gelatin, just as in a volcano, the magma will follow the path of least resistance. When
there is a fracture in the rock on the Earth’s surface, the magma will flow out of the
fractures. Otherwise, the magma flows in all directions.
7. Have the students do a volcanic prediction activity.
What to do
1. Place 10mL of baking soda in center of a sheet of bathroom tissue. Fold the corners
over the baking soda and crease the edges so that they stay in place. Place the tissue
packet in the middle of a large disposable pan.
2. Put modeling clay around the top edge of a funnel. Turn the funnel upside down over the
tissue packet. Press down to make a tight seal.
3. Put safety goggles on and add 50mL of vinegar and several drops of liquid dish soap to a
200mL beaker, and stir.
4. Predict how much time will elapse before your volcano erupts.
5. Pour the liquid into the upturned funnel. Using a stopwatch, record the time you began to
pour and the time your volcano erupts. How close was your prediction?
8. Discuss how scientists try to predict volcanoes and show them pictures of the
volcano sites around the world.
Reflection:
1. What worked?
The modeling of the volcanoes, especially the explosive eruption
demonstration went over pretty well. We did it a few times because the students
were begging for an encore. Be warned it gets a little messy. Also, the gelatin
volcano lava flow activity can be messy, but the students seemed to really enjoy
this one. They were captivated by the gelatin volcano and the lava tube setup.
The gelatin volcanoes work the best if you insert a straw by gently pushing in
while twisting back and forth. Then turn the lava tube and pegboard sideways,
so that you can gently insert the lava tube into the straw. The airline tubing fits
perfectly inside the straw and allows a tight fit. Finally, with small gelatin
volcanoes you need to provide cracks along the top, so have the students cut
small slits in the top of the volcano toward the sides. This way they can observe
that the liquid will for sure flow into the present cracks, deepening them with time.
We had many other interesting observations.
2. What didn’t work?
We didn’t have enough time to finish the last activity within our block
schedule class.
3. What would I change for the next time?
I think a larger volcano (2L bowl size) would be interesting for contrast and
with that I would still allow each of the students to apply lava. This would allow
the students to observe more long term changes with the shape of the volcano.
Also, this would be a lot smaller mess!