{"id":67676,"date":"2026-05-01T07:00:25","date_gmt":"2026-05-01T07:00:25","guid":{"rendered":"https:\/\/hygienewaste.co.za\/?post_type=product&#038;p=67676"},"modified":"2026-05-01T07:00:34","modified_gmt":"2026-05-01T07:00:34","slug":"watch-glasses-2","status":"publish","type":"product","link":"https:\/\/hygienewaste.co.za\/?product=watch-glasses-2","title":{"rendered":"Watch Glasses"},"content":{"rendered":"<p>Watch Glasses \ufffd\ufffd\ufffd A watch glass is a circular concave piece of glass used in chemistry as a surface to evaporate a liquid, to hold solids while being weighed, for heating a small amount of substance and as a cover for a beaker.<\/p>\n<p>Types of watch glasses<\/p>\n<ul>\n<li>Glass watch glasses \ufffd\ufffd\ufffd This can be reused after it is sterilized in an autoclave or a laboratory oven. The glasses made provide high resistance to thermal shock, chemical resistance and withstand mechanical durability.<\/li>\n<li>Plastic watch glasses \ufffd\ufffd\ufffd These are disposable watch-glass used in laboratory work to avoid any cross-contamination while preparing the samples. They are very good at implementing in low-temperatures and have an operating span of \ufffd\ufffd\ufffd57 to 135 \ufffd\ufffdC it can also resist UV light degradation. These plastic watch glasses are less expensive and light in weight<\/li>\n<\/ul>\n<p>Uses of watch glasses<\/p>\n<ul>\n<li>One of the generic uses of a watch glass as mentioned previously includes as a lid for beakers. In this case a watch glass is placed above the container, which makes it easier to control and alter vapour saturation conditions.<\/li>\n<li>A watch glass is often used to house solids being weighed on the scale. Prior to weighing desired amount of solid, a watch glass is placed on the scale, followed by taring or zeroing the scale so that only the weight of the sample substance is obtained.<\/li>\n<li>Watch glass can also be used for drying solids. When further drying is required, a watch glass is often used in cases where a particular type of solid needs to be separated from its comparatively volatile solvent. The solid is spread on a watch glass and, often time, a folded filter paper is placed above to keep out airborne particles from contaminating the product. <\/li>\n<li>To maximize the drying rate, a watch glass can be placed inside a fume hood to provide good air circulation for an adequate amount of time. Another technique used in chemistry laboratories to increase the drying rate is passing a gentle stream of dry air or nitrogen gas over the watch glass from an inverted funnel clamped above it.<\/li>\n<\/ul>\n<p>Add to Wishlist<\/p>\n<p> Add to Wishlist<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Watch Glasses<\/p>\n","protected":false},"featured_media":61346,"template":"","meta":{"content-type":""},"product_brand":[],"product_cat":[18441],"product_tag":[26051],"class_list":{"0":"post-67676","1":"product","2":"type-product","3":"status-publish","4":"has-post-thumbnail","6":"product_cat-lab-glassware","7":"product_tag-watch-glasses","9":"first","10":"instock","11":"shipping-taxable","12":"purchasable","13":"product-type-simple"},"jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/hygienewaste.co.za\/index.php?rest_route=\/wp\/v2\/product\/67676","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/hygienewaste.co.za\/index.php?rest_route=\/wp\/v2\/product"}],"about":[{"href":"https:\/\/hygienewaste.co.za\/index.php?rest_route=\/wp\/v2\/types\/product"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/hygienewaste.co.za\/index.php?rest_route=\/wp\/v2\/media\/61346"}],"wp:attachment":[{"href":"https:\/\/hygienewaste.co.za\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=67676"}],"wp:term":[{"taxonomy":"product_brand","embeddable":true,"href":"https:\/\/hygienewaste.co.za\/index.php?rest_route=%2Fwp%2Fv2%2Fproduct_brand&post=67676"},{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/hygienewaste.co.za\/index.php?rest_route=%2Fwp%2Fv2%2Fproduct_cat&post=67676"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/hygienewaste.co.za\/index.php?rest_route=%2Fwp%2Fv2%2Fproduct_tag&post=67676"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}