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natural gas trapped in fairy liquid bubbles and scooted into the air and then "lit" with a taper on the end of a very long stick :-)
taken @ the "Henkel sponsored" Chemistry Magic Show during Science Week in the Chemistry Dept at University College Cork, Ireland in Nov 2010
taken from the back of the lecture theatre with the long lens and a steady hand at the Royal Society of Chemistry Annual Lecture for Schools @ the Chemistry Dept University College Cork, Ireland, 18th May 2011
The lecture was titled “Chemistry and Light” and was given by Dr Peter Douglas and Dr Mike Garley, School of Chemistry, Swansea University.
It was a very interesting and also rather amusing lecture :-)
Step 8
The result of the experiment! The child just needs to place the pH paper onto the wet sample block. I should have put more liquid on A (tap water), and C (lemon juice) could use more too, but as you can see the colors are quite vibrant. Because the coffee filter is fairly translucent, the letters even show through (provided a decent-sized liquid spot was put down).
The student then can compare their colors to already tested-and-labeled pH paper strips to determine the nature of A, B and C. With a pH color scale they can also estimate the pH.
I had also tried out overlapping spots of lemon juice and baking soda to see if I could get an intermediate pH and then intermediate colors but there was no discernible gradient.
pH Color Scale Prop
I don't think this scale is quite accurate for cyanidin, the pigment in red cabbage. However, I did not want to dredge up sulfuric acid and sodium hydroxide to make my own, so I took it at face value as a reasonably close (and safer) alternative.
I got the hues from this journal article. The abstract printed there is a weird typo and totally out of place; the Thai researchers are making inexpensive anthocyanin solutions and paper so farmers can test waste water on their farms. I took the hues from Figure 11.
After printing out, I budget-laminated with overlapping packing tape, then sliced into strips (paper cutter again comes in handy). The children can then compare the color they get with the samples to these strips to estimate actual pH values.
Step 7
I printed up a grid of "A B C" and chopped into little squares with the paper cutter (I also included a shortened URL to this photo set).
Each sample (tap water, baking soda solution, lemon juice) is stored in a plastic container with a couple holes drilled in the lids. A cotton swab can then transfer a small drop of each sample onto the corresponding letter on the test sheet.
I went with this because I'm hoping it will avoid a lemon-juice-soaked catastrophe during the Science Night. By using pH paper (as opposed to the more tradditional liquid cabbage extract) and small amounts of sample, there will hopefully be less mess. Also, the children can take home the results. This is what it looks like after the pH paper has been placed over the spots.
For a big crowd of young children I'll be spotting the samples myself, to avoid cross-contamination (the lemon juice and baking soda neutralizing one another) or accidentally bringing back the pigment into the stock containers which could cause a child to (reasonably) question if the color came from the stock instead of from a reaction with the paper. For smaller groups or older students of course the kids could do the spotting themselves.
This educationally vivid complete experimental set-up of a gas chromatograph makes it possible to separate substances which are highly volatile at up to 100°C. A butane mixture is a suitable choice here, for example.
Mit diesem didaktisch durchsichtigen Komplettversuch eines Gaschromatographen können Trennungen leicht flüchtiger Substanzen bis 100 °C durchgeführt werden. Hierfür eignet sich z. B. ein Butan Gemisch.
Alle Bestandteile des offenen Systems wie Trägergasversorgung, Durchflussmessung, Trennsäule mit stationärer Phase, Temperiereinrichtung, Wärmeleitfähigkeitsdetektor und Schreiber sind deutlich zu erkennen, so dass eine anschauliche Erläuterung des Funktionsprinzips möglich ist.
In countercurrent distillation (rectification) using a column, the rising vapour can enter into interactions with the condensate. In this manner, a fractional distillation, i.e. a distillation in several steps for the separation of substances with similar boiling points, can be performed in a single apparatus. If bubble tray columns are used condensate can be removed from the individual bubble trays.
Bei der Gegenstromdestillation (Rektifikation) mittels einer Kolonne kann der aufsteigende Dampf mit dem Kondensat in Wechselwirkung treten. Auf diese Weise kann eine fraktionierte Destillation, d.h. eine Destillation in mehreren Schritten zur Auftrennung von Substanzen mit ähnlichen Siedepunkten, in einer einzigen Apparatur erfolgen. Werden Glockenbodenkolonnen verwendet, so kann von den einzelnen Glockenböden Kondensat entnommen werden.
Step 4
First drying. After the filters had some time to soak, I carefully lifted them out. Let excess juice drain back into the bowl. Place the whole stack on a cookie rack.
It is an exercise in frustration to separate wet coffee filters. Wait until they are mostly dry before trying. I got impatient and used a hairdryer to speed things up (while the pigment does not seem to stain badly, you still want to watch to make sure you don't blow a stack of purple-soaked filters onto the couch, a pet or your spouse).
At this stage, you can go do another round of extraction. Add more water to the cabbage bits (again, just enough to barely cover), heat again, and repeat with a new stack of filters. If this is just for fun at home, a single stack will last you for the next few years. For a big science fair, you'll probably want to do more.
In 1811, based on the similar behaviour of (ideal) gases when subjected to temperature and pressure increases (see gas laws) and on Gay-Lussac's law of volumes, Avogadro formulated the hypothesis that under the same pressure and temperature conditions, identical volumes must contain the same number of gas particles (molecules, atoms).
Avogadro stellte 1811 aufgrund des Gleichverhaltens der (idealen) Gase bei Temperatur- und Druckerhöhungen (siehe Gasgesetze), sowie des Volumengesetzes von Gay-Lussac die Hypothese auf, dass sich unter gleichen Bedingungen von Druck und Temperatur im gleichen Volumen die gleiche Anzahl von Gasteilchen (Molekülen, Atomen) befinden müssen.
TESS Chemistry Set 2 contains basic experiment material, e.g. support material. In combination with further sets, numerous experiments on General, Inorganic and Organic Chemistry as well as Food Chemistry and Chemistry of Polymers can be performed.
TESS Chemie Set 2 beinhaltet Grundgeräte, wie z.B. Stativmaterial. Mit Set 2 alleine sind keine Experimente durchführbar. In Kombination mit weiteren Sets können Experimente zur allgemeinen, anorganischen und organischen Chemie sowie zur Lebensmittel- und Polymerchemie durchgeführt werden.
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Durch erhöhte Energiezufuhr, wie etwa im Lichtbogen, können die beiden atmosphärischen Gase Stickstoff und Sauerstoff zur Reaktion gebracht werden. Dabei bilden sich Stickoxide, die mit Wasser zu Salpetersäure reagieren.
Complete device compilation for a comfortable way to derive the ideal gas laws experimentally with help of the Cobra4 Senor-Unit Thermodynamics and the glass jacket system.
Vollständige Gerätezusammenstellung um komfortabel mit der Cobra4 Sensor-Unit Thermodynamics und dem Glasmantelsystem die Gasgesetze experimentell zu erarbeiten.
If a sub-layer of copper (II) sulphate and potassium hexacyanoferrate (III) is introduced into a solution of ammonium hydroxide and ammonium sulphate in a U-tube with the help of a suspended level bulb (dry vessel) and a DC voltage is applied, it can be seen that yellowish hexacyanoferrate ions migrate towards the anode and the blue-coloured copper ions move towards the cathode.
Unterschichtet man eine Lösung aus Ammoniak und Ammoniumsulfat im U-Rohr mit Hilfe des Niveaugefäßes (Trockenrohr) mit einer Lösung aus Kupfer(II)sulfat und Kaliumhexacyanoferrat(III), so beobachtet man nach Anlegen einer Gleichspannung, wie die gelblich gefärbten Hexacyanoferrat-Ionen zur Anode und die blau gefärbten Kupfer-Ionen zur Kathode wandern.
The reaction of sebacoyl chloride with hexamethylenediamine forms Nylon 610°C. The two components are dissolved in two solvents of different density which do not mix with one another.
Durch die Reaktion von Sebacinsäuredichlorid mit Hexamethylendiammin bildet sich Nylon 610°C.
Eudiometer Plastic tube with valve andgraduation, length 500 mm,diam. 20 mm.
Zur Untersuchung der Volumenverhältnisse bei Reaktionen von Sauerstoff und Wasserstoff.
The TESS Chemistry set 1/2 consists of two equipment sets which belong together. Both are needed to perform the experiments. In total 111 student experiments can be carried.
TESS Chemie Set 1/2 besteht aus zwei zusammenhängenden Gerätesets, die beide zur Durchführung der Versuche benötigt werden. Insgesamt können 111 Schülerversuche durchgeführt werden.
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Elektrofilter werden in der Industrie z. B. zur Abgasreinigung in Kraftwerken und Heizungsanlagen, zur Reinigung von Gichtgasen, Generatorengas u.v.a.m. eingesetzt. Um im Schulversuch den Aufbau einfach zu halten, wird das Prinzip eines Elektrofilters mit Hilfe von Zigarettenrauch demonstriert. In einem Hochspannungsfeld werden die Schwebepartikel des Rauches elektrisch aufgeladen und schlagen sich dann auf der Anode bzw. Kathode als Belag nieder. Das Gas, das die Entstaubungskammer anschließend verlässt, ist nahezu völlig von Stäuben u.ä. befreit.
No. 9 Coal Mine & Museum in Lansford, PA - this is inside the museum building, which was small but had some interesting artefacts on display.
Winter vacation to The Poconos, Feb 2009.
Step 5
When they are mostly dry, you can take a crack at peeling them apart. Little fingers help here, so recruit the kids. At this stage you probably don't have to get them individual; if only two are stuck together I think they will still dry fine. Arrange them on towels and let dry overnight (or as long as it takes to dry out).
As mentioned, the color seems to wash out ok, but you probably still don't want to use the "good towels" for this.
I was disapointed at first because while they were drying many filters looked very pale. However, they darkened nicely after drying, and still produced vibrant colors when used.
The molar mass of a liquid is determined by injecting a small amount of it into a heated gas syringe. The liquid evaporates and the gas generated drives the plunger out of the syringe.
Die molare Masse einer Flüssigkeit wird bestimmt, indem eine kleine Menge davon in die aufgeheizte Gasspritze injiziert wird. Die Flüssigkeit verdampft und das entstehende Gas treibt den Kolben der Gasspritze aus dem Spritzenkörper hinaus.
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Um Gips (CaSO4 · 2 H2O) als Baustoff nutzen zu können muss er zuvor aufbereitet werden. Dies geschieht durch den sogenannten Gipsbrand, bei dem ein Teil des Kristallwassers durch starkes Erhitzen aus dem Gips herausgetrieben wird. Mit Wasser verrührter gebrannter Gips bindet innerhalb kurzer Zeit ab und erstarrt dabei zu einer harten festen Masse.
Step 3
Now we need to saturate some coffee filters. Use white ones so the colors show clearly. I took a stack of about a dozen and flattened them into a shallow dish.
Carefully pour the (hot!) juice onto the filters. The ground-up cabbage is sneaky and will try, milkshake-like, to suddenly lunge out of the bowl and onto the filters. Pour slowly, and do not worry about getting the very last bit. I used a strainer to catch stray pieces, and to gently press around the edges of the filter paper. You want the liquid to go over the edges so it has a chance to flow into the pieces in the middle of the stack.
I let the stack sit for 15-20 minutes. Because the juice is hot it helped to evaporate the water.
Apparatus for demonstrating fractional distillation of petroleum.
Apparatur zur Demonstration einer fraktionierten Erdöldestillation.
No. 9 Coal Mine & Museum in Lansford, PA - this is inside the museum building, which was small but had some interesting artefacts on display.
Winter vacation to The Poconos, Feb 2009.
Across the globe PHYWE is one of the preferred suppliers for all products and services needed for the teaching of pure science and its technical applications in schools, colleges and universities.
PHYWE ist einer der weltweit bevorzugten Systemlieferanten für alle Produkte und Dienstleistungen zu naturwissenschaftlicher Aus-und Weiterbildung und deren technische Anwendungen und Applikationen an Schulen und Hochschulen.
This set allows the computer-assisted measuring and evaluation of temperatureand pressure in a comfortable way for experiments with the "Set gas laws withglass jacket".
Bei Experimenten zu den Gasgesetzen erlaubt dieses Set das computerunterstützte Erfassen und Auswerten von Temperatur und Druck auf komfortable und einfache Art und Weise mittels des Messwerterfassungssystems Cobra3.
Passing an electric current through a solution can cause chemical reactions. Here the current is the driving force of the redox reactions that occur.
eitet man elektrischen Strom durch eine Lösung, so kann es dabei zu Stoffumwandlungen kommen. Der Strom ist dabei die treibende Kraft der ablaufenden Redoxreaktionen.
In order to determine the heating capacities of commercially available solid fuels (coal, coke, lignite, peat, etc), pieces weighing 0.5 to 1 g are used. Wood and peat have to be air-dried, and coal and lignite have to be stored under dry conditions.
Zur Bestimmung der Heizwerte fester Brennstoffe (Steinkohle, Koks, Braunkohle, Torf, Holz, etc.) verwendet man 0,5 bis 1 g schwere Stücke der handelsüblichen Ware. Holz und Torf müssen luftgetrocknet, Steinkohle und Braunkohle trocken gelagert sein.
Material to equip school groups for deriving electrochemical fundamentals in an 8-10 hour practical session. All the equipment is contained on a tray with clearly organised compartments.
Schülergruppenausrüstung zur Erarbeitung der elektrochemischen Grundlagen in einem 8- bis 10-stündigem Praktikum. Alle Geräte auf einem Tablett mit Fächern übersichtlich angeordnet.