Elephant's toothpaste

File:Elephant (1).ogg

About 50 ml of concentrated (>12%){{Cite episode|title=Elephant's Toothpaste (slow motion)|url=https://www.youtube.com/watch?v=nfGXG8Lnndc|series=Periodic Table of Videos|publisher=The University of Nottingham|access-date=2016-09-14|archive-url=https://web.archive.org/web/20160928022022/https://www.youtube.com/watch?v=nfGXG8Lnndc|archive-date=2016-09-28|url-status=live}} hydrogen peroxide is first mixed with liquid soap or dishwashing detergent. Then, a catalyst, often around 10 ml potassium iodide solution or catalase from baker's yeast, is added to make the hydrogen peroxide decompose very quickly. Hydrogen peroxide breaks down into oxygen and water. As a small amount of hydrogen peroxide generates a large volume of oxygen, the oxygen quickly pushes out of the container.{{cite web|title=The Great Elephant Toothpaste Experiment!|url=https://www.pbs.org/parents/adventures-in-learning/2013/10/the-great-elephant-toothpaste-experiment/|website=PBS Parents|date=2013-10-09|access-date=2019-04-26|archive-url=https://web.archive.org/web/20190426082059/https://www.pbs.org/parents/adventures-in-learning/2013/10/the-great-elephant-toothpaste-experiment/|archive-date=2019-04-26|url-status=live}} The soapy water traps the oxygen, creating bubbles, and turns into foam. About 5-10 drops of food coloring could also be added before the catalyst to dramatize the effect. How rapidly the reaction occurs will depend on the concentration of hydrogen peroxide used.{{cite web|title=Elephant Toothpaste: A Hydrogen Peroxide Chemistry Experiment|url=http://www.using-hydrogen-peroxide.com/elephant-toothpaste.html|website=Using Hydrogen Peroxide|access-date=2017-10-19|archive-url=https://web.archive.org/web/20171011223907/http://www.using-hydrogen-peroxide.com/elephant-toothpaste.html|archive-date=2017-10-11|url-status=live}}

This experiment shows the catalyzed decomposition of hydrogen peroxide. Hydrogen peroxide (H₂O₂) decomposes into water and oxygen gas, which is in the form of foam, but normally the reaction is too slow to be easily perceived or measured:

: 2H2O2 -> 2H2O + O2 ^

In normal conditions, this reaction takes place very slowly, therefore a catalyst is added to speed up the reaction, which will result in rapid formation of foam. The iodide ion from potassium iodide acts as a catalyst and speeds up the reaction while remaining chemically unchanged in the reaction process.{{cite journal|last1=Dirren|first1=Glen|last2= Gilbert|first2=George|last3= Juergens|first3=Frederick|last4=Page|first4=Philip|last5=Ramette|first5=Richard|last6=Schreiner|first6=Rodney|last7= Scott|first7=Earle|last8=Testen|first8=May|last9=Williams|first9=Lloyd|title=Chemical Demonstrations|journal=A Handbook for Teachers of Chemistry.|date=1983|volume=1|issue=1 |pages=180–185|doi=10.1021/ed062pA31.2|bibcode=1985JChEd..62R..31K|doi-access=free}} The iodide ion changes the mechanism by which the reaction occurs:

: $\backslash begin\{array\}\{llllll\}$

\ce{H2O2}

&+\

\ce{I-}

&\ce{->

H2O}

&+\

\ce{IO-}

\\

\ce{H2O2}

&+\

\ce{IO-}

&\ce{->

H2O}

&+\

\ce{O2 ^}

&+\

\ce{I-}

\\

\hline

\ce{2H2O2}

&

&\ce{->

2H2O}

&+\

\ce{O2 ^}

&

&\Delta_\mathrm{r}H^\circ = -196\text{ kJ/mol}

\end{array}

The reaction is exothermic; the foam produced is hot (about 75°C or 167°F).{{Specify|reason=The reaction is hot (around 75°C)|date=January 2023}} A glowing splint can be used to show that the gas produced is oxygen.{{cite web|title=Catalytic Decomposition of H₂O₂ – Elephant's Toothpaste|url=https://ncsu.edu/project/chemistrydemos/Kinetics/Elephants%20Toothpaste.pdf|website=NCSU Chemistry Lecture Demonstrations|access-date=2015-12-06|archive-url=https://web.archive.org/web/20160125045148/https://ncsu.edu/project/chemistrydemos/Kinetics/Elephants%20Toothpaste.pdf|archive-date=2016-01-25|url-status=live}}

The rate of foam formation measured in volume per time unit has a positive correlation with the peroxide concentration (v/V%), which means that more foam will be generated per unit time when a more concentrated peroxide solution is used.{{cite journal|title=Elephant Toothpaste|journal=Journal of Chemical Education|volume=94|issue=7|pages=907–910|doi=10.1021/acs.jchemed.7b00040|year=2017|last1=Hernando|first1=Franco|last2=Laperuta|first2=Santiago|last3=Kuijl|first3=Jeanine Van|last4=Laurin|first4=Nihuel|last5=Sacks|first5=Federico|last6=Ciolino|first6=Andrés|hdl=11336/43230|hdl-access=free}}

File:Materials, 2017, elephant toothpaste.jpg

YouTube science entertainer Mark Rober has created a variation of the experiment, named "Devil's Toothpaste", which has a far more pronounced reaction than the version usually performed in classroom settings.{{cite web | url=https://nerdist.com/article/tallest-ever-elephant-toothpaste-fountain-world-record/ | title=NASA Engineer Sets Elephant Toothpaste Fountain World Record }}{{cite web | url=https://fox8.com/news/youtuber-mark-rober-throws-birthday-party-for-rocky-river-boy-with-brain-cancer/ | title=YouTuber Mark Rober throws birthday party for Rocky River boy with brain cancer | date=22 September 2020 }} The ingredients to create the devil's toothpaste reaction are the same as the regular elephant's toothpaste reaction, the only difference being the use of 50% H₂O₂ instead of the usual 35%. {{cite web | url=https://www.youtube.com/watch?v=KERPITDcPDQ | title=Mark Rober's Secret Devil's Toothpaste Recipe Revealed | date=March 2023}}

• Black snake (firework)
• Carbon snake
• Soda geyser

{{Reflist}}

{{commons category|Elephant's toothpaste}}

• [https://sciencebob.com/fantastic-foamy-fountain/ The Elephant's Toothpaste Experiment] sciencebob.com

Category:Chemistry classroom experiments

Category:Articles containing video clips