Glass Plates

Quick Answer: Laboratory glass plates are flat, square sheets of glass used as covers, work surfaces and simple apparatus in school science. The listing photograph shows plates of more than one size, used for covering gas jars and dishes, mineral hardness tests, capillarity demonstrations and germinating seeds between two sheets.

Common Practical Uses

• Covering gas jars, beakers and evaporating dishes to keep gases in or dust out
• The scratch step of mineral identification, testing whether a specimen is harder than glass
• Showing capillary rise between two plates held at a narrow angle in coloured water
• Germinating seeds on moist blotting paper held between two plates, so root growth can be watched
• A flat, easily cleaned surface for mixing small amounts of stain or modelling clay

Plain Glass, Many Jobs

A flat glass plate is one of the simplest items in a science store, but it turns up in chemistry, biology and earth science. Smeared lightly with petroleum jelly, it seals the ground rim of a gas jar. Laid over a beaker of pond water or an evaporating dish, it keeps dust out while letting students see inside. Because glass is harder than many common minerals and softer than others, it also serves as a reference surface when students test whether a mineral can scratch it.

In biology, two laboratory glass plates held together with rubber bands around a sheet of wet blotting paper make a germination chamber. Seeds tucked between paper and glass grow in view, so students can follow roots turning downwards and root hairs forming, and can rotate the plates to study gravitropism. Two plates touching along one edge and slightly open along the other also show capillary action: coloured water climbs highest where the gap is narrowest.

The listing photograph shows square plates in at least two sizes, with the slight green tint at the edges that ordinary sheet glass often has. The title does not give sizes, thickness, glass type or whether the edges are ground smooth, so confirm these before ordering. The smaller glass streak plates in this range suit bench kits.

Care & Handling

• Handle plates by the faces with dry hands until you know the edges are ground; cut glass edges can be sharp.
• Store plates on edge in a rack or flat with paper between them, never loose in a drawer where they scratch and chip.
• Remove grease with warm water and detergent, then rinse; a scratched or chipped plate should be taken out of use.

Specifications

Why Choose LabEquip

Science stores buy glass plates in quantity because many departments share them. LabEquip lists them in Biology Lab Products, and earth-science teachers often add a Mineral Test Kit for hardness practicals. Use the LabEquip contact page to confirm size, thickness and edge finish.

Frequently Asked Questions

Are the edges of the glass plates smoothed?

The title does not say whether the edges are ground or left as cut. Until this is confirmed at enquiry, handle the plates by their faces and store them so the edges are protected.

Can the glass plates be heated?

They are not meant for direct heating. Ordinary sheet glass expands unevenly when heated in one spot and can crack. Use borosilicate apparatus or a heat-resistant mat when something hot has to be covered or supported.

How are glass plates used in a mineral hardness test?

Press a sharp edge of the mineral firmly across the glass and then wipe the mark. A true scratch means the mineral is harder than glass; a powder line that rubs off means it is softer.

How do two glass plates show capillary action?

Hold two clean plates together along one vertical edge with a thin spacer at the other, and stand them in coloured water. The water rises between them in a curve, highest where the gap is narrowest.

How do I set up seeds to germinate between glass plates?

Line one plate with wet blotting paper, place seeds between paper and glass, cover with the second plate and hold the pair with rubber bands. Stand it upright in a shallow tray of water and keep it out of direct sun.

How should greasy plates be cleaned?

Wipe off most of the petroleum jelly with a paper towel first. Then wash in warm water with detergent, rinse well and dry the plates standing on edge.

Last Updated: September 2026