384 1-800-452-1261
Pressure—Fluids, continued
Capillary Equilibrium Tube
Normally water in a series of commonly connected tubes at the same height would
all reach equilibrium due to equal air pressure on the columns. But in this demonstration
the diameter of some of the tubes is so small that the force of capillary action
pulling up on the water is greater than the air pressure above the water, thus pulling
the water even higher. Since the force of capillary action is essentially constant for
a particular liquid, the cross-sectional area of the tube is the determining factor for
the final height of the water. The four tubes and reservoir form a single all-glass unit
that is held upright in its enclosed stand. Detailed exploration of capillary force is
included.
Catalog No. Description Price/Each
AP4734 Capillary Equilibrium Tube $60.68
Capillary Equilibrium Tube
AP4734
Adhesion Disk
An impressive hands-on demonstration of adhesive surface tension. Hang the 7.5-cm
glass disk by its three precisely coordinated hanging cords over a container of liquid.
Then let the disk rest on the surface of the liquid. Students can feel the force required
to pull the disk free. For quantitative results, a spring scale can be used to measure
the actual force and compare it to the weight of the disk alone. Different liquids can
also be compared to determine their adhesive surface tension.
Catalog No. Description Price/Each
AP6027 Adhesion Disk $48.16
Adhesion Disk
AP6027
Viscosity Demonstration Tubes See page 177.
Useful Scientific Conversion Factors and Physical Constants
Some Conversion Factors
Length 1 in = 2.54 cm
1 cm = 0.394 in
1 km = 0.6214 mi
1 mi = 1.609 km = 5,280 ft
1 m = 39.37 in = 3.281 ft = 1.094 yd
1Å = 1 x 10–10 m = 0.1 nm
Area 1 m2 = 1 x 104 cm2 = 10.76 ft2 = 1,550 in2
1 ft2 = 0.0929 m2 = 144 in2
Volume 1 L = 1,000 cm3 = 61.02 in3 = 33.81 oz
1 gal = 4 qt = 8 pt = 128 fl oz = 3.786 L
1 fl oz = 29.58 mL
1 Tbsp = 3 tsp = 14.8 mL
1 cup = 237 mL
Mass 1 oz = 28.35 g = 0.0625 lb
1 kg = 2.20 lb
1 lb = 16 oz = 453.6 g = 0.4536 kg
Density 1 g/cm3 = 62.43 lb/ft3 = 0.03613 lb/in3
Pressure 1 torr = 1 mm Hg = 1.32 x 10–3 atm
1 atm = 760 torr = 1.01 x 105 Pa = 14.7 lb/in2
Energy 1 J = 107 erg = 0.239 cal
1 cal = 4.184 J
Time 1 year = 365.25 days = 8,766 hours
1 year = 5.26 x 105 min = 3.156 x 107 sec
Temperature °C = 5/9 (°F – 32)
°F = 9/5 (°C) + 32
K = °C + 273.15
Some Physical Constants
Atomic mass unit amu 1.6606 x 10–24 g
Avogadro’s number N 6.0221 x 1023/mol
Boltzman constant k 1.3807 x 10–23 J/K
3.3000 x 10–24 cal/K
Charge of an electron e 1.6022 x 10–19 C
Curie Ci 3.70 x 1010 dps
Electron volt eV 1.602 x 10–19 J
3.829 x 10–20 cal
Faraday constant F 96,485 C/mol e–
Gas constant R 8.315 J/mol • K
0.08206 (L •-atm)/(mol-•-K)
Mass of an electron me 9.1094 x 10–28 g
5.4858 x 10–4 amu
Mass of a neutron mn 1.6749 x 10–24 g
1.0087 amu
Mass of a proton mp 1.6726 x 10–24 g
1.0073 amu
Planck’s constant h 6.626 x 10–34 J • s
1.584 x 10–34 cal • s
Speed of light c 2.9979 x 108 m/s
(in vacuum)
Acceleration of gravity g 9.80665 m/s2
(standard value)
Speed of sound 331 m/s
(in air at STP)
Some Metric Prefixes
p n μ m c d k M G
pico nano micro milli centi deci kilo mega giga
10–12 10–9 10–6 10–3 10–2 10–1 103 106 109
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