Bubbles

Bubbles (sometimes referred to as overhead items) are sprites shown above players' heads when performing many different actions in RuneScape Classic. Creating complex animations requires memory and time, especially for 2-dimensional sprites such as those used for players, which need to be painstakingly redrawn for each frame. Thus, role-playing aids such as text in the chat box and bubbles are used instead. Generally speaking a bubble will appear for gathering skills when using the appropriate tool with the resource scenery (fishing spot, mining rock, or tree), for production skills when interacting with the helper resource scenery (furnance, anvil, range, potter's wheel, pottery oven, spinning wheel), when attempting to get something from scenery such as water, sand, wool, rock samples, and when opening 'special' doors or after doing intermediate steps.

They are always the same as an item's icon.

Bubbles appear for the following actions:
 * Skilling
 * Cooking - the food appears after it is used on a range or fire
 * Crafting - a gold bar appears and a silver bar appears when crafting with gold or silver
 * Firemaking - a tinderbox, when it is used with logs lying on the ground
 * Fishing - a fishing rod or other fishing equipment, when fishing at a fishing spot
 * Mining - a pickaxe, after clicking on a rock
 * Smelthing - ore, when it is used with a furnace
 * Smithing - a bar, when it is used with an anvil
 * Woodcutting - an axe, after clicking on a tree or machette after clicking on Jungle
 * Skill-related
 * Cooking:
 * Using grain on a hopper - a grain, after adding it to the hopper
 * Getting milk - an empty bucket appears after it is used on the cow
 * Creating Onion Mixture - an onion after adding it to a bowl
 * Creating Tomato Mixture - a tomato after adding it to a bowl
 * Creating Onion and Tomato Mixture - an onion or tomato depending on which you add to complete
 * Creating Onion and Tomato and Ugthanki Mix - a cooked ugthanki meat after adding it to the Onion and Tomato Mixture
 * Baking Pitta Bread - an Uncooked Pitta Bread when it is used on a range
 * Cooking Tasty Ugthanki Kebab - A Pitta Bread when it is used on a Onion and Tomato and Ugthanki Mix or vice versa
 * Baking bread - a bread dough when it is used on a range
 * Baking pizza - an Uncooked Pizza when it is used on a range
 * Baking pie - an uncooked pie when it is used on a range
 * Crafting:
 * Moulding soft clay - soft clay when used on a Potter's wheel
 * Firing bowl - an unfired bowl after firing it at a Pottery oven
 * Firing pie dish - an unfired pie dish after firing it at a Pottery oven
 * Firing pot - an unfired pot after firing it at a Pottery oven
 * Using shears on sheep - shears, even if wool is not obtained
 * Spinning flax - flax, when it is used with a spinning wheel
 * Spinning wool - wool, when it is used with a spinning wheel
 * Cooking seaweed on range - a seaweed, producing soda ash
 * Using either sand or soda ash on a furnace, whilst having both in inventory - a bucket of sand or soda ash, depending which one was used
 * Herblaw:
 * Grinding bat bones or a lump of charcoal - shows pestle and mortar
 * Using Jangerberries on unfinished guam potion - shows the jangerberries to get unfinished ogre potion
 * Adding ground bat bones to unfinished ogre potion - shows the ground bat bones
 * Using Ammonium Nitrate on nitroglycerin - shows the Ammonium Nitrate to produce mixed chemicals (2 chemicals)
 * Using ground charcoal on mixed chemicals (2 chemicals) - shows the ground charcoal to produce mixed chemicals (3 chemicals)
 * Using arcenia root on mixed chemicals (3 chemicals) - shows the arcenia root to produce explosive compound
 * Mining:
 * a panning tray, when panning at the Digsite
 * a trowel or Rock pick, when excavating the Digsite with the trowl or rock pick, respectively
 * Miscellaneous
 * Drinking - Dwarven Stout, Wine or Tea
 * Using water sources - an empty vial, bucket, or jug appears after it is used on the water source
 * Getting sand - an empty bucket appears after it is used on the Sand pit
 * Opening doors:
 * Using Jail keys on a door in the Taverley dungeon jail
 * Using Brass key on the door to access the shortcut to the Edgeville dungeon
 * Using Dusty Key on the door to access or leave the Blue Dragon area in Taverley dungeon
 * Using Closet Key on the closet door at Draynor Manor, during Ernest the Chicken quest
 * Pulling a Christmas cracker
 * Repairing a cannon during Dwarf Cannon using the toolkit.
 * Getting tackled, or tackling during Gnome Ball (minigame) by a Gnome Baller

(This list is incomplete, you can help by [ expanding it].) 

Trivia

 * Mining Blurite ore does not produce the mining bubble.
 * Fishing Giant Carp does not produce the fishing bubble.
 * Using a Rock pick at the incorrect digging site will not give a bubble.
 * When moulding soft clay, the bubble appears before the player selects what to make.
 * The only bubbles that appear for Herblaw are for quest related items.
 * Actions that require distinct elements in the player's inventory will show the bubble of the first item used, for instance if making steel bars and using first iron ore on furnance, the iron bubble will be shown. If making molten glass and soda ash is first used then that will be shown.
 * As opposed to woodcutting showing the axe that was used, when mining only one pickaxe bubble is shown, not depending on the pickaxe used. This was since variations of pickaxes came after bubbles were implemented.
 * RuneScape 3 features a discontinued piece of content which is a reference to the skilling bubbles in Classic