Background information The thing that makes soda bubbly is invisible carbon dioxide gas that has dissolved into the water. The

carbon dioxide gas (CO2) is pumped into bottles at the bottling factory using tons of pressure. The gas

mostly stays dissolved in the liquid and cannot expand to form more bubbles, which gases naturally do,

until you open the bottle and pour out the soda. If you shake the bottle and then open it, the gas is

released from the protective hold of the water molecules and escapes with a whoosh, taking some of the

soda along with it.

Warm soda tends to fizz much more than cold soda. Why? The warmer the liquid, the less gas can be

dissolved in that liquid. The colder the liquid, the more gas can be dissolved in that liquid. This is

because when the liquid is heated; the gas within that liquid is also heated, causing the gas molecules to

move faster and faster. So, they will diffuse (move) out of the liquid, leaving less gas dissolved in that

liquid. In colder liquids the gas molecules are moving very slowly, causing them to diffuse out of

solution much more slowly, and more gas tends to stay in solution. At the bottling plant, carbon dioxide

is pumped into the cans or bottles when the fluid is very coldaround 35 degrees Fahrenheit. This low

temperature allows the maximum amount of carbon dioxide to dissolve in the soda.

What other ways can you cause the gas to escape? The CO2 that's dissolved in the water of any carbonated drink can be driven out by adding something

else to that. For example, adding salt to soda causes it to foam up because thousands of little bubbles

form on the surface of each grain of salt. Why?

No matter how smooth a solid substance may feel to you or me, they have tiny pits are called nucleation

sites. Nucleation sites are places where the carbon dioxide can make bubbles. A nucleation site can also

be a scratch, a speck of dust, tiny cracks, or crevices. The increase in the formation of bubbles causes the

CO2 to rapidly degas (opposite of adding gas to a liquid using pressure) out of the liquid, taking some of

the liquid with it.

Why then Mentos?

Each Mentos candy has thousands of tiny pits all over the surface. In other words each candy has

thousand of nucleation sites. As soon as the Mentos hit the soda, the liquid in the bottle comes into

contact (touches) with the candy. Then the trapped gas leaves the liquid and forms bubbles at the

nucleation sites that are all over the surface of the candy. Also, Mentos candies are heavy and sink to

the bottom of the bottle. When all this gas is released, it literally pushes all of the liquid up and out of the

bottle in an incredible soda blast.

This information was taken directly from the following web sites:

http://www.stevespanglerscience.com/experiment/00000109

http://www.smm.org/buzz/buzz_tags/nucleation_sites

Name: _______________________

Class: _______________

Date: __________

Coke Zero and Mentos Lab

After watching a clip of Mythbusters investigating the Coke and Mentos phenomenon, answer the

following questions:

1. What did taking the CO2 out of the bottle do to the reaction?

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2. What did the normal soda water do to the reaction?

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3. What effect do the nucleation sites (surface area on the Mentos) have on the reaction?

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4. In the space below, demonstrate your understanding of nucleation. Make sure to include CO2

molecules, surface of a Mentos, and direction arrows.

5. What did taking the CO2 out of the bottle do to the reaction?

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6. What did the normal soda water do to the reaction?

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7. What effect do the nucleation sites (surface area on the Mentos) have on the reaction?

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Your goal is to think of a way in which you could cause the highest geyser formed by

the Coke Zero and Mentos reaction. Be creative as you will be graded on effort. Dont

worry about it being right or wrong.

1) Question: ________________________________________________________________

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2) Hypothesis: ______________ Diet Coke and Mentos will make a higher geyser,

because__________________________________________________________________

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3) Identify the Variables

Independent Variable:______________________________________________________

Dependent Variable:_______________________________________________________

Control Variables: _________________________________________________________

Experimental Group: _______________________________________________________

Control Group: ____________________________________________________________

4) Materials (per group):

3 x 1.5 L bottle of Coke Zero

1 Thermometer

1 Mentos Geyser Launch Tube

3 x 4 Mint Mentos candies

1 Giant Metric Ruler (butcher paper).

1 Data Table (per student)

Container with hot water

Container with ice water

4) Procedure:

Inside:

1. Understand your role in this experiment: Coke Handlers (A), Thermometer

Handler (B), Mentos Holders(C), and the Mentos droppers(D).

2. Coke Handlers (A) carefully retrieves Coke Zero from the corner of the

room (do not shake or drop!). Make sure to take one Coke from the hot water

container, one coke from the ice water container, and one coke at room

temperature.

3. Mentos holder (C) receives exactly 12 Mentos in a plastic container.

4. All students line up at the door in two lines (quietly) with the following:

Data Table

Pencil/Pen

Packed-up backpacks on their back.

Failure to be quiet in the stairway or outside will result in you losing 20-30 points

from your lab grade (100 points)!Coke handlers MUST carefully carry the

Coke Zero outside without dropping it!

Outside Experimentation & Measurement:

1. Line up shoulder to shoulder by your group number outside the school

entrance.

When it is your groups turn (starting with group 1), step up to the area

under the stairs near the entrance under the giant paper ruler.

2. Coke Handler GENTLY places the Coke in the square container and

carefully takes the cap off the Coke.

3. The Thermometer handler will get the thermometer from Mr. Logan and

take the temperature of their Coke Zero, making sure to keep the

thermometer in the Coke Zero for 15 seconds.

4. All student record the temperature in the data table.

5. The Mentos dropper will place 4 Mentos in the geyser tube, then Mr.

Logan will attach the geyser tube to your Coke Zero.

6. Mentos dropper (D) pulls then pin when told to do so.

7. Students watch for maximum height achieved.

8. All students write down results and observations then compare with

group members.

9. Coke handler recaps the Diet Coke bottle and places it on the ground

near their feet.

10. Repeat until all teams are finished. If everyone is calm and on task, you will have the option of drinking the Diet Coke before going back to

class.

6) Data Table

Table 1: Diet Coke & Mentos Fountain results

Temperature of Coke Zero

(oC)

Height of Geyser (m) Observations

Group 1

Cold

Room

Hot/Warm

Group 2

Cold

Room

Hot/Warm

Group 3

Cold

Room

Hot/Warm

Group 4

Cold

Room

Hot/Warm

Group 5

Cold

Room

Hot/Warm

Group 6

Cold

Room

Hot/Warm

7) Data Analysis (Graph)

In the space below draw your scatter graph to show a direct, indirect or no relationship

between temperature of Coke Zero and Height of Geyser.

8) Observations: (5 senses.):

Write down some of the characteristics of the materials before you added them together?

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What happened when you added the materials? ___________________________________

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Were there any mistakes or errors? If yes, what were they? __________________________

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9) Observation Analysis Questions

Does changing the temperature of Diet Coke have an effect on the height of the geyser?

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How are you able to explain that it was the temperature and not another factor that

caused the change in height?

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What explanation can you come up with to explain why temperature effects the height

of the Coke Zero and Mentos Geyser?

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____________________________________________________________________________ 11. Conclusion

HINT: if you are having trouble writing your conclusion, start off by re-stating your hypothesis. Then use

the following guiding questions as they relate to your hypothesis. Make sure that you write/type the

conclusion in a paragraph format

What happened during the experiment?

What went as planned?

What problems did your group/class encounter?

If given the chance to go back, how would you fix this problem?

How was this experiment related to how molecules move when energy is added? How did you learn this?

How would you conduct another related experiment next, knowing what you know after completing this

lab?

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MIDDLE SCHOOL LAB REPORT GUIDELINE

Title (Title page)

(Name) ____________________________

(Date) _______________ ( on title page, underneath the title)

Title:

The Front page of the report

Name, Date, Class (on the front page, underneath the title)

A brief, concise (the use of few words to convey much information), yet descriptive title

Following pages:

Statement of the Problem (It is the question you are going to investigate or try to answer):

What question or questions are you trying to answer?

Include any observations or background information about the subject

Hypothesis:

Write prediction to what you believe will happen

Make sure this prediction is written as a complete sentence

Make sure the statement is testable

The statement should reference the independent and dependent variables: such as

The plant group receiving (independent variable i.e. fertilizer) will (dependent variable i.e.) produce more

fruit than the plants that did not receive fertilizer (control)

Materials:

Make a list of all items used in the lab

Also should include a drawing of any set up that is used.

In the case of the Coke Zero and Mentos experiment, you should have an illustration (drawing)

of how the Mentos launcher works.

Procedure:

Write a paragraph or a list which explains what you did in the lab.

Your procedure should be written so than anyone else could repeat the experiment.

Results:

This section should include any data tables, observations, or additional notes you make during

the lab.

Although some students may wish to attach the original data: Dont! It is important to always

preserve the original

You may attach a separate sheet(s) if necessary.

All tables, graphs and charts should be labeled appropriately.

Conclusions:

Accept or reject your hypothesis

EXPLAIN why you accepted or rejected your hypothesis using data from the lab.

Include a summary of the data averages, highest, lowest, etc. to help the reader understand

your results.

List one thing you learned and describe how it applies to a real-life situation.

Discuss possible errors that could have occurred in the collection of data (experimental errors)

Special considerations for your conclusion:

Conclusion Dos and Donts

Dont list the data again, but summarize, discuss, and analyze the data.

Do explain why your hypothesis was correct or incorrect from your observations or data.

Dont give the procedure again, but do point out possible sources of error.

Dont forget to break up your ideas with more than one paragraph. Your conclusion is an essay.

Helpful format for writing a conclusion

(length of blank lines does NOT indicate the length of your entries additional sentences are

encouraged)

This lab (experiment) investigated ________________________________________________.

In order to study the problem we _________________________________________________.

My results showed _________________________________, thus proving my hypothesis was

(correct/incorrect).

I believe the results are (accurate/inaccurate) because _______________________________.

In order to further investigate this problem, next time I would _______________________.

The above guide was adapted from Cheryl Randalls Science Lab Report found at http:

donnayoung.org/apologia/lab/labhow~cr.htm