An accordion is an instrument that is played by squeezing it to make air flow through it, so it is sometimes called a squeezebox. It has a keyboard on one side you can play a tune on, and buttons on the other side that you can play preset chords with.
Bagpipes are a musical instrument most people associate with Scotland, although various forms of bagpipes have been played in lots of different countries. Someone who plays bagpipes is called a piper.
Bagpipes, as the name suggests, are made from an airtight bag with several pipes attached to it. The pipes are a chanter that you use to play tunes, and one or more drones that make a continuous noise. The piper keeps the bag full of air by blowing into it, and squeezes air out of it with their arm. You can't stop bagpipes from making noise while there is air in the bag.
Banjos were originally made by African slaves in America to look like an instrument from their homeland. Banjos are today used in bluegrass and folk music, and have a distinctive sound. The body of a banjo is round and does not have a hole in it.
A bell is a metal object with a distinctive shape. They usually hang with the open end pointing downwards. Bells ring when the clapper inside hits the side of the bell when the bell is moved. Some bells don't have a clapper, and are rung by hitting them with a special hammer.
The bell in the picture is a big church bell, and there is an owl sitting just above it.
Castanets are small percussion instruments that you hold in your hand. They are shaped like a pair of cockle shells, with a slightly hollowed out center. You hold them in your hand and close them quickly to make a sharp clacking noise. Castanets are usually played in pairs, one in each hand.