Introduction: Do It Yourself Lab Ware
This DIY lab ware Instructable was written for Tekla Labs, whose "mission is to empower scientists all over the world to build their own research infrastructure." These DIY lab ware are from a series of articles I've written for my column The Square Root of Not (http://www.science20.com/square_root_not) at Science 2.0 (http://www.science20.com). I wrote the articles to promote the Science Play and Research Kit Competition (SPARK) and to inspire readers to design their own kits for the SPARK Competition (http://www.reimaginechemset.org/). Here's part of the press release for SPARK:
October 15, 2013 (Palo Alto, Calif.) – The Gordon and Betty Moore Foundation, in collaboration with Society for Science&the Public (SSP) today announced the launch of a new competition focused on creating the equivalent of the chemistry set for the 21st Century. The Science, Play and Research Kit (SPARK) Competition challenges participants to generate a new set of experiences and activities that encourage imagination and interest in science, bringing the spirit of the classic chemistry set to today’s children.
“Renowned inventors, researchers and innovators – including our co-founder, Gordon Moore –often attribute their early fascination with science to their childhood chemistry sets. More than just toys, these sets often fueled an interest in, a lifelong appreciation for, and a dedication to various fields of science and engineering,” said Steve McCormick, president of the Moore Foundation. “Gordon’s childhood chemistry set ultimately ignited a technology revolution, and new versions of these experiences should kindle the next generation of excited, motivated and science-captivated researchers, explorers and fans.”
The SPARK competition seeks creative ideas for modern science exploratory experiences that are accessible and spark a child’s imagination. The Moore Foundation and SSP believe the contest will result in ideas that will ignite a new generation of great scientific minds and science enthusiasts.
The competition is searching for entrants from all walks of life, from elementary school teachers to tenured professors and digital developers to graduate students. The contest focuses on science beyond chemistry, seeking ideas for new tools that tap into the spirit of the classic chemistry set and encourage children to wonder how and why the world works.
The deadline for the Tekla Labs Build My Lab Contest is 16 December 2013 and I've attempted to include as much DIY lab ware as time permitted. For any lab ware that I didn't have time to document here, you can go to www.science20.com and in the search box on the upper right type "science play and research kit" and click the go button. I have written several other DIY articles, so feel free to browse my column: http://www.science20.com/square_root_not.
Step 1: DIY Titration Lab Ware
You often see demonstrations of titration using an expensive glass burette, but you can build titration lab ware using a disposable serological pipette, a solder sucker bulb, and a ring stand or support stand. For this build I’m using my erector set support stand (I sometimes call it my Bunsen burner stand). Titration is the process of determining the unknown concentration of a solution by adding a known amount of a solution with a known concentration. For example, in an acid-base titration, you can determine the unknown concentration of an acid in a solution by adding a base solution of known concentration. If you are designing your own Science Play and Research Kit, you could provide a bottle of NaOH (sodium hydroxide, or lye) at 0.1 M to 0.4 M solution and phenolphthalein solution for your indicator. There are a number of web pages that demonstrate this process that you can reference. To demonstrate how phenolphthalein solution reacts to acids and bases, you can use ordinary household ammonia and white vinegar.
Goggles (to protect your eyes from splashes)
Disposable gloves (vinyl, latex, or nitrile)
Protective clothing (lab coat, or clothes that you would wear when using ammonia for cleaning)
Ring stand (I used my Erector set ring stand)
Burette clamp (I used a magnetic chip clip modified with an Erector set two hole right angle—it is attached to the stand with a computer case thumbscrew and Erector set lock nut)
Serological pipette (5 ml or 25 ml)
Solder sucker bulb (if you prefer, you can use a pipette pump or pipette bulb)
4 250 ml beakers
Distilled or deionized water (or you can use tap water since all that is being demonstrated is the phenolphthalein color change)
Wear protective clothing, goggles, and gloves. Pour 150 ml of water (for this experiment, ordinary tap water will do) in the beaker. Use the eye dropper to add four drops of phenolphthalein solution to the beaker. Add 50 ml of ammonia to the second beaker and 50 ml of vinegar to a third beaker. The fourth beaker contains distilled or deionized water to rinse the Mohr pipette.
Remove the tip from the solder sucker bulb and attach the bulb to the top of the pipette (the cylinder with the cotton plug). Attach the pipette to the ring stand.
I find it easier to use the 25 ml pipette. With the 5 ml pipette, you have to be careful not to squeeze the bulb too hard and draw too much liquid into the pipette. You only need small amounts of ammonia or vinegar to demonstrate the phenolphthalein solution color change. Nonetheless, it’s an excellent opportunity to practice using the lab ware for titration experiments you may wish to design for your kit.
Draw a small amount of ammonia into the pipette then set the beaker of ammonia aside and slowly add the ammonia to the beaker with the 150 ml of water and phenolphthalein solution (swirl the liquid in the beaker if needed). With the 25 ml pipette I counted 13 drops per milliliter; you shouldn't have to use a full milliliter to turn the phenolphthalein magenta. Squeeze the remaining ammonia out of the pipette back into the beaker of ammonia. Rinse the pipette with the distilled water.
Next, draw a small amount of vinegar into the pipette. Then set the beaker of vinegar aside. Slowly add the vinegar to the beaker with the 150 ml of water, ammonia, and phenolphthalein solution, drop by drop, until the liquid becomes colorless again (swirl the liquid in the beaker if needed).
Rinse the pipette with distilled water. This is a simple demonstration of how to use the home made titration lab ware and how phenolphthalein solution reacts in the presence of acids and bases. Dispose of the vinegar, ammonia, and your experiment solution as you normally would dispose of household ammonia and vinegar according to the requirements of your local area.
Solder sucker picture source: http://monome.org/community/uploads/2008/11/solder_sucker.jpg
25 ml serological pipette picture source: http://www.genfollower.com/portfolio-item/25ml-serological-pipette/
Step 2: DIY Laser Interferometer
Parts needs from the Laser Tripwire set:
2 Adjustable mirrors
Cardboard backing from a 8 ½ X 11 notepad
Sheet of blank white printer paper 8 ½ X 11
Large binder clip
A magnifying lens (mine came from my telescope)
Something to prop the lens on (I used my copy of The Complete Works of Shakespeare)
If you don’t have the Spynet Laser Tripwire set you can replace the parts with a cat toy (laser pointer) and two makeup mirrors. Here’s an excellent video by Celtic Mad Scientist that demonstrates how to build the interferometer (sorry, couldn't embed the video, you'll have to click the following link):
Step 3: Demonstrate the Tyndall Effect…With Frickin’ Laser Beams
You can use a laser to demonstrate the Tyndall effect. A simple cat toy (laser pointer) will do but for this demonstration I’ll be using the laser from my DIY Laser Interferometer. “The Tyndall effect, also known as Tyndall scattering,” according to Wikipedia, “is light scattering by particles in a colloid or particles in a fine suspension.” You can use the laser to test three different mixtures: solutions, colloids, and suspensions (source: http://en.wikipedia.org/wiki/Tyndall_effect).
250 ml beaker
Table salt (NaCl)
Dirt from your garden
Stir 5 grams (1 teaspoon) of table salt (NaCl) into a beaker with 250 ml (about 8 ounces) of water. Stir until all the salt (solute) dissolves in the water (solvent). Shine the laser pointer thru the beaker containing the saline solution…and…nothing interesting happens. When the NaCl dissolves in water it separates into sodium (Na+) cations and chloride (Cl-) anions too small to be seen with the naked eye and will not scatter the light from the laser beam. Solutions are homogeneous mixtures, that is, the water molecules, sodium cations, and chloride anions are uniform throughout the mixture. The mixture is stable (the salt, once dissolved, won’t settle to the bottom of the beaker) and the salt cannot be filtered from the water.
You’ll need an eyedropper with a small amount of milk, a teaspoon, and a beaker with 250 ml of water. Squeeze a few drops of milk from the eyedropper into the beaker and stir. Shine the laser through the beaker and you should now be able to observe the Tyndall effect.
You’ll notice that you can’t see the laser beam piercing through the air, but you can see the beam in the diluted milk and water mixture. A glass of milk is an example of a colloid and the Tyndall effect is what gives it its translucent appearance. Milk is mostly an emulsion of milk fat and water. An emulsion is “a suspension of small globules of one liquid in a second liquid with which the first will not mix” (source). Oil and vinegar do not mix, but vinaigrette is an emulsion of oil and vinegar. “Emulsion” is used to describe a colloid of two or more liquids (in the case of milk, milk fat droplets dispersed in water) as opposed to, say, an aerosol colloid like fog (water droplets dispersed in air). The milk fat globules are too small to be seen with the naked eye or even through an optical microscope, but (unlike a solution) are large enough to scatter light and create the Tyndall effect. Colloids are visually homogenous (uniform throughout), but microscopically heterogeneous (lumpy/grainy--in this case, the globules of milk fat remain separate from the water). Generally, colloids cannot easily be filtered nor settle at the bottom of the beaker.
Stir 5 grams (1 teaspoon) of dirt from your garden into a beaker with 250 ml (about 8 ounces) of water. Before the dirt settles, shine the laser pointer thru the beaker. You should be able to observe the Tyndall effect before the particulate (the particles of dirt suspended in the water) settles to the bottom of the beaker. Suspensions are heterogeneous (lumpy/grainy—the grains of dirt suspended in the water). Particles in a suspension are usually large enough to see with the naked eye or be viewed through an optical microscope. They are often large enough to be filtered from the water, and, of course, will eventually settle to the bottom of the beaker.
Step 4: Fluorescence
Nowadays you can find inexpensive key chain lights that include a visible light LED flashlight, but also include a red laser LED and UV LED. The red laser can be used to demonstrate the Tyndall effect, and the UV LED can be used to demonstrate a lot of stuff that becomes visible under UV light. I found the above black light (UV) LED strobe light on clearance after Halloween for around $2.00.
The beaker filled with cloudy liquid is actually a few drops of milk in water that I used to demonstrate the Tyndall effect. The next two pictures show the beaker with the UV LEDs off and then the UV LEDs on.
There’s a lot of stuff that will fluoresce under UV light:
Milk (as demonstrated here)
Urine (that’s what those trippindicular black lights you can buy at Petco are for—but you can drag those old black light posters of Jimmy Hendrix out of the attic if you want).
Tonic water (the quinine flavoring in the tonic water)
The security strip on US currency
See this web page for more stuff that will fluoresce under UV light: http://chemistry.about.com/cs/howthingswork/f/blblacklight.htm
Also take a look at the black light photo gallery: http://chemistry.about.com/od/glowinthedarkprojects/ig/Black-Light-Photo-Gallery/
You can perform a simple demonstration of UV fluorescence using a Q-tip, some colorless liquid laundry detergent, and watercolor paper. Pour a small amount of colorless liquid laundry detergent into the cap of the bottle to use as an ink well. Dip one of the cotton swab ends of the Q-tip into the laundry detergent and use the Q-tip as a pen to write a message on the watercolor paper. Wait until the detergent dries and then shine the UV light on the message to make it visible.
I used watercolor paper since 8.5 X 11 in. 20# computer printer paper will itself fluoresce under UV light and possibly obscure the message. Watercolor paper is off-white making it easier to view the message (see photo of blank page above).
The next two pictures picture are a beaker with some laundry detergent dissolved in 250ml of water with the UV LEDs off and then the with the LEDs switched on.
The final picture is the message illuminated on the watercolor paper using the UV LEDs.
Step 5: K'nex Ball Mill
You may wish to include a mortar and pestle among your lab ware, but you might want to consider including a ball mill. Here’s one I built out of K’nex parts. I’m always looking for ways to re-purpose special event/trade show swag. I used the ball bearings form a Magnetix knock-off given out at trade shows. The ball mill was able to turn granulated sugar into powdered sugar in a few minutes.
Step 6: K’nex Test Tube Rack
I often see K’nex sets at second-hand stores like Goodwill or Salvation Army so I decided to see if K’nex can be co-opted for science. The this is a test tube rack that I built out of K’nex.
Step 7: Snap Circuits Conductivity Tester
1 555 Timer IC
1 250 ml beaker
Snap Circuits Parts:
1 Base Grid (11” x 7.7”) # 6SC BG
1 Eight-Pin IC Socket # 6SC ?U8
0.02uF Capacitor # 6SC C1
1 Variable Resistor #6SC RV
1 Whistle Chip # 6SC WC
1 4.5 Volt Battery Holder # 6SC B3
1 Slide Switch # 6SC S1
Jumper Wire 18" (Black) # 6SC J1
Jumper Wire 18" (Red) # 6SC J2
1 Single Snap Conductor # 6SC 01
5 Conductor with 2-snaps # 6SC 02
2 Conductor with 3-snaps # 6SC 03
2 Conductor with 4-snaps # 6SC 04
1 Conductor with 5-snaps # 6SC 05
2 Conductor with 6-snaps # 6SC 05
Build the circuit shown in the first picture. You can design your own Snap Circuits by downloading the Snap Circuits Designer from this web page: http://www.snapcircuits.net/learning_center/designer
The next three pictures are the step by step build.
Once the circuit is built, use a clothespin to fasten the end of the red Jumper Wire (that’s not connected to the 555 circuit) to one side of the beaker. The snap should be reach all the way to the bottom of the beaker. Use the second clothespin to fasten the end of the black Jumper Wire (that’s not connected to the 555 circuit) to opposite side of the beaker with the snap against the side of the beaker and all the way to the bottom.
Now you can test the conductivity of various solutions. Switch the Slide Switch (S1) on. No sound will be heard on the piezoelectric speaker WC (Whistle Chip). Slowly pour your solution into the cup until the liquid level reaches the red and black snaps of the Jumper Wires inside the cup. This will close the circuit of the 555 test circuit and you will hear a tone on the speaker (WC). When you are finished rinse the beaker and the snaps with distilled water.
First test: precipitation
In this demonstration, I test the conductivity of precipitation. It’s actually melted snow that I collected in a clean bottle, but you can use rain water.
In this demonstration, I test the conductivity of ordinary tap water from the kitchen sink.
Click this link to watch the video: http://vimeo.com/71832949
Third test: distilled water
Funny story. I planned to demonstrate that distilled water does not conduct electricity. I went to a compounding pharmacy to ask if they sold distilled water in smaller volumes than 1 gallon (3.7854 L). They do not, so I asked if I they had distilled water in their lab and the pharmacy tech was kind enough to provide me with about 100 ml of distilled water. And without further ado, here’s the distilled water test:
Click this link to watch the video: http://vimeo.com/71831543
Well that should not have happened! Since distilled water does not conduct electricity, you should not hear anything on the piezoelectric speaker.
For this article, I wanted to demonstrate first that distilled water does not conduct electricity and then add few grams of table salt (NaCL). When salt is dissolved into water it separates into sodium (Na+) cations and chloride (Cl-) anions. Missing an electron, the sodium ion has a positive charge and the chloride ion having an extra electron, has a negative charge. Opposites attract. The sodium (NA+) cations are attracted to the black snap which is connected to the negative side of the battery. The chloride (Cl-) anions are attracted to the red snap which is connected to the positive side of the battery. This forms a conductive path between the two snaps. Electrons flow into the water from the negative side of the battery through the black snap and are attracted to the sodium ions. The sodium ions pass the electrons to the chloride ions which then flow to the red snap connected to the positive side of the battery. With the circuit closed, you hear a tone on the piezoelectric speaker.
There are a few reasons why the experiment with the distilled water failed. The beaker and snaps may not have been clean. There could have been contaminants in the cough syrup bottle. The pharmacy tech may have given me ordinary tap water by mistake. Anyway, I decided to build my own distillation lab ware and test it when I am able to to generate my own distilled water (see last picture)
You’ll probably recognize a few of the items in the picture such as the 250 ml beaker, the Erector set ring stand, and the alcohol lamp and stand from this Instructable: https://www.instructables.com/id/DIY-Alcohol-Lamp/
The pipette and chip clip (not part of the apparatus) are from the DIY Titration Lab Ware step above. The flask is a 250 ml flat bottom Florence flask. The cork is from a Champagne bottle (technically a sparkling wine bottle). The Y-shaped tubing connector courtesy http://dynalon.com/. The rubber tubing is from a stethoscope. The plastic cone is a conical plastic planter. The silver pebbles are courtesy Lab Armor (they are thermal beads to replace water in laboratory baths: http://www.labarmor.com/lab-armor-beads-for-lab-water-baths/).