General Laboratory your Fahnestock clips Equipment to the ... · General Laboratory Equipment Science Laboratory Workbench Purpose: This is a simple science all-purpose worktable

1 “Oilcloth” means linoleum in this context. Vinyl flooring is a good substitute.

2 See Appendix A for a list of material sources.

3 Electrical connectors used on the power supply.

General LaboratoryEquipment

Science LaboratoryWorkbench

Purpose: This is a simple science all-purposeworktable that can be easily built in any homeor schoolroom. The laboratory contains a pow-er supply, sink, and water source.

Material: Old table (or you may build one), 1”× 12” boards for shelves, two gallon jugs orlarge oil cans, glass tubing, rubber tubing, abucket, and a funnel.

What to Do: Any old table can be convertedinto a science workbench. Cover the table withoilcloth1 (tack or glue down) or a piece of ⅛”masonite (cost about $5.00). Cut a hole just alittle smaller than the diameter of a gallon jugin the top of the table as shown. This is for yoursink. Cut the bottom 3” off the jug with yourbottle cutter. Smooth the edges with a file oremery paper (see “Bottle Cutter” on page 18). In-sert a #6½ one-hole stopper2 into the neck ofthe bottle. Connect a rubber hose to the stop-per with a short piece of glass tubing. This is

your drain hose, and it should run into abucket.

The wash bottle serves as a supply of water.The supply of water is controlled by a clothes-pin that serves as a stopcock, as shown on thenext page.

Make your shelves and place them on top ofthe table. Nail them to the table through theside strips at the bottom. The shelves shouldhave a plywood or masonite backing. Theshelves should be spaced to store your scienceequipment, so plan the sizes with this in mind.You can store your chemicals and glass tubingin the drawer if your table has one. If not, planyour shelves so you don’t waste space and yetcan store materials safely.

Mount your power supply (see “AC or DC Pow-er Supply” on page 126) under the table with thewires coming through holes in the table. Attachyour Fahnestock clips3 to the top of the table.From here you can tap off either direct or alter-nating current.

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Figure 1-1 Shelving: Above is a possible arrangement of

shelves for your worktable. You can build the shelves

with 1” × 12” pine boards as shown in the drawing.

Modern Safety Practice

Never “prime” (start) a siphon by mouth on any-thing that you do not actually intend to drink.You can easily end up with a mouthful! See“Modern Safety Practice” on page 10 for moreabout the hazards of using your mouth in the lab-oratory and “Wash Bottle” on page 28 for a solu-tion that doesn’t require you to blow into thefunnel.

Your worktable should be placed so you canplug your power supply into a regular outletplug.

Gravity Wash Bottle

Purpose: This provides a steady supply of wa-ter, and the container can be easily refilled.

Material: Gallon jug, #6½ stopper (two-hole),glass tubing, plastic funnel, rubber tubing, anda clothespin.

What to Do: Insert your funnel and glass tub-ing through one hole in the stopper (see “This-tle Tube” on page 33). Bend the other piece oftubing in your alcohol burner. Insert the longend through the rubber stopper. Slip a piece ofrubber tubing over the glass tubing and use aclothespin to stop the flow of water.

Operation of Equipment: Place the bottle inposition. Fill the bottle through the funnel.Suck on the end of the rubber tubing to startthe water flowing (siphon) and then clamp thetubing with a clothespin. You can also start the

4 Make: The Annotated Build-It-Yourself Science Laboratory

Gravity Wash Bottle

4 Incandescent light bulb, not fluorescent or LED.

Safety Tips

1. Be careful the black material in the neckof the bulb does not fly out.

2. Be careful not to work so fast that youbreak the bulb. Don’t shove the filethrough the bottom of the bulb.

3. Do not try to use a fluorescent bulb. Thematerial inside is harmful.

Modern Safety Practice

See Note 2 in Appendix E for safety guidelineswhen working with glass. Chiefly, wear safetyglasses and take care to avoid cutting yourselfwith pieces of glass that may break.

water to flow by blowing into the funnel. Thebottle should be placed so the hose is directlyover the gallon jug sink.

Light Bulb Chemistry Flask

Purpose: To make a glass flask that can beheated and can be used with stoppers.

Material: Burned-out light bulb4 of any size orshape.

Helpful Hints for Building: Bend back thesoft metal tip on the end of the bulb with a pairof pliers or your fingernail. Twist the metalpiece so that it breaks off. You will see a hole inthe top of the bulb. Use a pointed file or a smallscrewdriver to break the black material aroundthe hole. A pair of diagonal pliers can be usedto break the black substance away. After theblack material is broken into pieces, turn thebulb over and shake it. Stick a file through thehole and break the wire holding the filament orcenter part in the bulb. Shake this out. If youhave bent the edge of the top of your flask, youcan make it round again by turning it on theend of any piece of round wood such as abroom handle.

Operation of Equipment: If the light bulb isround on the bottom, use a coffee can tripod(see “Tripod and Adjustable Rings” on page 14)to support the bulb. The heated flask may behandled by a pair of tongs (see “Ring Supportfor Support Stand and Test Tube Holder” on

page 16). The stoppers may be purchased fromany scientific supply house or can be made bydrilling corks (see “X Connector” on page 37).

Can You Work Like a Scientist?

1. What is the black material? Can youtest it to see if it is an electrical conduc-tor?

2. Is the metal tip at the top of the bulbmade out of iron? How can you testthis?

3. What is the difference between a bulbthat is burned out and one that is not?Try both types and see.

4. What does a fluorescent bulb have in itthat makes it different from a regularbulb? Do not try to open a fluorescentbulb.

5. Is there a type of bulb that has a wideneck? Look at floor lamp bulbs and

5Chapter 1: General Laboratory Equipment

Light Bulb Chemistry Flask

5 Careful! It is not cool enough to touch after 10 seconds!

Modern Safety Practice

See Note 2 in Appendix E for safety guidelineswhen working with glass.

large bulbs that are used to light class-rooms and gymnasiums.

6. Could you use a soda straw as glasstubing for your flask? If you didn’t havea stopper, how would you seal theopening in the flask?

Cutting Glass Tubing

Purpose: Glass tubing comes in lengths of fourfeet from scientific supply houses or in longerlengths from neon sign companies. Ordinaryglass tubing costs about $1 - $2 a foot. It is veryhelpful to be able to cut tubing to the exactlength needed.

Materials: Glass tubing (any length) and a file.

What to Do: Place the piece of glass tubing ona smooth surface. Draw the sharp edge of thefile across the tubing at the place you want bro-ken. Just one firm stroke in one direction willdo. Then place your thumb on the oppositeside of the tubing from the mark. Press withyour thumbs, and the tubing should snapeasily.

Operation of Equipment: Dip the tubing insoapy water before trying to insert it into atight hole in a rubber stopper. If you have dril-led holes in a cork for your rubber stopper, sealthe holes around the tubing with wax (eitherfrom a candle or paraffin).

Bending Glass Tubing

Purpose: Many experiments call for glass tub-ing bent in different shapes. To buy such benttubing is very expensive. Tubing can be bentwith any good source of heat such as a bunsenburner, propane torch, or alcohol lamp.

Materials: Glass tubing, source of heat (alco-hol lamp, propane torch, or bunsen burner).Most alcohol lamps take much longer to bendtubing than do the other two heat sources. Apropane torch is not expensive and is of greathelp in a science laboratory.

What to Do: Turn the heat up quite high onyour torch or burner. Turn the piece of glasstubing in the flame. Slowly bring the tubingnearer the tip of the flame. As the glass heats, itbends easily. Bend the tubing to the shape youwant, and then hold it in position away fromthe flame until the glass cools enough to set(about 10 seconds5). In order to bend perfectcurves, it is necessary to put an attachment onthe burner so that the flame will reach two orthree inches of the tubing at the same time.

6 Make: The Annotated Build-It-Yourself Science Laboratory

Cutting Glass Tubing

6 Originally “graduate” here. This terminology has fallen out of favor. Use the term “graduated cylinder” for clarity.

7 See Note 5 in Appendix E about baby bottles.

Safety Tips

1. Be very careful of the open flame. Makesure the torch is firmly supported.

2. Don’t touch the part of the tubing thatwas heated. Glass will retain heat formany minutes.

Modern Safety Practice

In addition to working with room temperatureglass (Note 2 in Appendix E), this project also in-volves open flames and hot glass.

See Note 3 in Appendix E for basic safety practicewhen working with open flames.

See Note 4 in Appendix E for basic safety practicewhen working with hot glass.

Graduated Cylinder andChemistry Flask

Purpose: A graduated cylinder6 is used tomeasure accurately amounts of a liquid. It hasmany purposes in chemistry, such as measuringamounts of chemicals and figuring volumes ofsolids, such as rocks.

Materials: Baby bottle7 or other straight-sidedbottle, medicine dropper with measuringmarks.

What to Do: The baby bottle is a wonderfulsource of science equipment. It is calibrated incubic centimeters and also in ounces. The stan-dard size is 240 cc. It can be heated with the al-cohol burner, and when used with a size #6½stopper, it makes an excellent flask. Also, be-cause of its shape, it makes a very good testtube.

You can make your own graduated cylinder byusing a narrow straight-sided bottle and a med-icine dropper. Place a piece of tape down oneside of the bottle. The medicine dropper is fig-ured in cubic centimeters. Fill your bottle withwater by using the medicine dropper. Add upthe number of cc’s as you go along and markthese on the piece of tape you are using for ascale.

Can You Work Like a Scientist?

1. Fill your graduated cylinder half full.Note the reading on your scale. Nowdrop a small rock into the bottle. Is thelevel of water higher or lower? Whatdid you add to the water besides therock?

2. If all you did was add the rock to thewater, could you find the volume (howmuch space it fills) of the rock from theheight of the water in the graduatedcylinder?

7Chapter 1: General Laboratory Equipment

Graduated Cylinder and Chemistry Flask