Aspirator Bottle

Quick Answer: The Aspirator Bottle is a laboratory bottle with an outlet near its base, so liquid can be drawn off from the bottom by gravity. It serves as a reservoir for distilled water or solutions and, in biology, as the suction source that pulls air through respiration experiments.

How an Aspirator Bottle Works

Because the outlet is at the bottom, the bottle empties under gravity whenever the outlet is opened, so a tap or clipped tube delivers liquid without pouring or pumping. Filled from the top and set on a shelf above the bench, it acts as a small reservoir for distilled water, buffer or staining solution, and the liquid level can be topped up without moving the bottle.

The name comes from its second use. When a bottle full of water is allowed to empty, air must enter through the top to replace the water, and if the top is connected by tubing to other apparatus, that air is drawn through it. Biology teachers use this in the classic demonstration that living things give off carbon dioxide: air passes first through soda lime or potassium hydroxide solution to remove carbon dioxide, then through lime water to show it is clear, over germinating seeds or small animals, and finally through a second lime water flask that turns milky before reaching the aspirator. The rate of water flow sets the rate of air flow.

The listing does not state capacity, glass type or the outlet fitting. A version with a screw cap and tubulation is listed too, and other variants are described on their own pages.

Uses in the Biology Lab

• Drawing air through the lime water apparatus in respiration experiments with seeds or small animals
• Holding distilled water at the staining bench for rinsing slides
• Supplying a steady flow of water to simple flow-through apparatus
• Displacing water to measure the volume of gas collected in simple experiments

Specifications

Care & Handling

• Stand the bottle on a firm, level shelf or support; it is heavy when full and the outlet makes it easy to knock over on a sloping surface.
• Rinse and drain it regularly so stored distilled water does not grow algae or biofilm.
• Loosen the stopper or cap slightly while dispensing so air can enter and the flow does not stop.
• Do not heat it; thick-walled reservoir bottles are not made for direct heating.

Why Choose LabEquip

School and college biology labs buy an aspirator bottle both for everyday distilled water supply and for respiration practicals, so one bottle often serves two jobs. LabEquip lists it in Biology Lab Products; give the capacity you need through the contact page.

Frequently Asked Questions

What is the outlet at the bottom for?

It lets liquid run out under gravity through a tap or clipped tubing, so the bottle can be used as a reservoir. As liquid leaves, air is drawn in at the top, which also makes it a gentle suction source for apparatus.

How does the bottle pull air through a respiration experiment?

As water runs out of the lower outlet, air must enter at the top to take its place. If the top is connected to a chain of flasks, air is drawn through them at a rate set by the water flow.

Why does lime water turn milky in the experiment?

Carbon dioxide from the living material reacts with calcium hydroxide in the lime water to form insoluble calcium carbonate, which clouds the solution.

Why has the flow from my bottle stopped?

If the top is sealed, a partial vacuum forms as liquid leaves and the flow stops. Loosen the cap or stopper, or fit a vent tube, so air can replace the liquid.

Can the bottle store reagents other than water?

Yes, most aqueous solutions, provided the outlet fitting and any tubing resist the chemical. Label the contents clearly and clean the bottle before changing to a different solution.

What capacity and outlet fitting does it have?

Bottles of this type are made in a range of sizes with either a stopcock or a tubulation for rubber tubing. The listing does not give these details, so confirm them when you enquire.

Last Updated: September 2026