Pipette Dropping Glass - Single 125mm Glass Pipette with Rubber Teat

This single 125mm glass dropping pipette with a rubber teat is a standard lab tool for transferring liquids drop by drop. It's a narrow glass tube tapered to a fine tip, with a replaceable rubber teat (bulb) on top.

Key Features

• Size: The 125mm length (about 5 inches) is a handy short size for drawing liquid from standard reagent bottles or test tubes.
• Material: The body is borosilicate or soda-lime glass, resistant to most chemicals and easy to sterilise.
• Rubber teat: A flexible bulb that creates the suction to draw up liquid. It can be removed for cleaning.
• Controlled delivery: The tapered tip gives even drops, which matters for qualitative analysis and indicator tests.

Common School Applications

• Adding indicator: Adding drops of phenolphthalein or litmus solution during titrations.
• Micro-chemistry: Mixing small volumes of reactants on a spotting tile.
• Microscopy: Placing a single drop of water or stain on a slide before adding a coverslip.
• Staining: Applying methylene blue or iodine to specimens like onion skin cells.

Care and Maintenance

• Cleaning: To prevent cross-contamination, separate the glass tube and rubber teat and wash both thoroughly after each use.
• Storage: Don't store the pipette with liquid in the teat, as chemicals can break down the rubber over time.
• Safety: Check the glass tip for chips or cracks before use, to avoid injury or uneven drops.

Specifications

• Material: Clear glass and rubber
• Size: 125mm
• Volume: About 1.5ml to 2.0ml
• Teat: Rubber
• Printing: None
• Product of China

How many drops per ml? A standard 125mm glass dropping pipette gives about 20 drops per millilitre. That's a common rule of thumb in science labs, but the exact number depends on:

• Viscosity: Thicker liquids (like oils or glycerine) form bigger, fewer drops.
• Surface tension: Soapy water or alcohol form much smaller, more frequent drops than pure water.
• Tip diameter: A chipped or wider tip gives bigger drops, so fewer per ml.

Tip: If you need precision, a good introductory exercise is to have students calibrate their own pipettes by counting how many drops of water it takes to reach the 1ml or 5ml mark in a measuring cylinder.