Salt (sodium chloride or table salt) produces big crystals and you can colour them to make them easier to see.
\nTry phenyl salicylate also known as Salol. This solid melts at 41 to 43 degrees C so if some is placed in a test tube and then placed in hot water it becomes a liquid. Students can then drip some onto a slide and the crystals form almost instantly. It is available from Crown Scientific and Perth Scientific Equipment.
\nAlso try ammonium chloride, magnesium sulfate and sodium thiosulphate.
\nSpecific experiments:
\nFAST AND SLOW COOLING
\nMaterials:
\nConical flask 150 ml
\n25gm copper sulfate
\n50mL water
\nFew drops of concentrated sulfuric acid
\n1.Supply 2 flasks containing 25 grams of copper sulphate and 50 mL of water.
\n2. Heat and dissolve the copper sulphate, forming a saturated solution.
\n3. Cool one flask quickly by placing in a bucket of ice.
\n4. Cool the other slowly by wrapping the flask in cotton wool, then alfoil.
\n5. Leave both flasks overnight.
\n6. Examine the crystal formations.<\/p>\n
DEMONSTRATIONS OF CRYSTAL FORMATION
\nThe formation of crystals can be demonstrated on an overhead projector or with a video-flex.
\nCopper sulfate, potassium nitrate and alum (aluminium potassium sulfate) produce the best crystals.
\nMaterials:
\nSaturated solution
\nGlass petri dish
\nHot plate or Bunsen burner
\nJar of the solid chemical
\nMethod:
\nBoil 50 mls of the saturated solution.(For saturated solutions,look up solubility table. At 20 degrees Celsius: copper sulfate 20.5 gm per 100ml water; potassium nitrate 31.6gm per 100ml Alum 6.3 g per 100ml)
\nAdd more solid until no more dissolves.
\nWhile still hot, pour a thin layer into a petri dish.
\nView on an OHP or through a video flex.
\nResults:
\nCopper sulfate:
\nCrystals start to form within 10 minutes. If left overnight, the whole dish is covered in the familiar shaped crystals.
\nPotassium nitrate:
\nIn test tube, does not form immediately. Overnight, structures of tall crystals form.
\nOn petri dish, crystals start to form after 5 minutes. Particularly spectacular if left overnight.
\nAlum which is Aluminium potassium sulfate:
\nPetri dish- forms small crystals within a few minutes. These grow fairly rapidly into beautiful shapes.
\nTest tube-not very interesting.
\nPotassium chlorate:
\nProduces the best crystals in a test tube, the crystals falling out of solution as you watch.
\nSodium nitrate:
\nCrystals are not very interesting, with a fuzzy mass forming in the petri dish.<\/p>\n
If you want to investigate other ideas, type in crystal growing or crystal recipes in a web search.<\/p>\n","protected":false},"excerpt":{"rendered":"
Salt (sodium chloride or table salt) produces big crystals and you can colour them to make them easier to see. Try phenyl salicylate also known as Salol. This solid melts at 41 to 43 degrees C so if some is placed in a test tube and then placed in hot water it becomes a liquid. […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4],"tags":[],"class_list":["post-227","post","type-post","status-publish","format-standard","hentry","category-experiments"],"_links":{"self":[{"href":"https:\/\/ciderhousetest.com\/labnetwest26\/wp-json\/wp\/v2\/posts\/227","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ciderhousetest.com\/labnetwest26\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ciderhousetest.com\/labnetwest26\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ciderhousetest.com\/labnetwest26\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/ciderhousetest.com\/labnetwest26\/wp-json\/wp\/v2\/comments?post=227"}],"version-history":[{"count":0,"href":"https:\/\/ciderhousetest.com\/labnetwest26\/wp-json\/wp\/v2\/posts\/227\/revisions"}],"wp:attachment":[{"href":"https:\/\/ciderhousetest.com\/labnetwest26\/wp-json\/wp\/v2\/media?parent=227"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ciderhousetest.com\/labnetwest26\/wp-json\/wp\/v2\/categories?post=227"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ciderhousetest.com\/labnetwest26\/wp-json\/wp\/v2\/tags?post=227"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}