I will share what I did, but for more detailed instructions see DK's 101 Great Science Experiments, A step by step guide.
Build a Banjo!
I attached a length of wood (that I let Malachi paint) to a plastic container by cutting two "I" shapes under the rim of the tub opposite each other. I bent the flaps of the "I" shapes out and pushed the end of the wood through the holes. I then used colored tape to decorate the tub and make the lines on the wood. Originally, I stretched a balloon over the tub and taped it to the sides, but the balloon broke. So I took the lid to the tub and cut it to fit inside and taped it to the wood. Then I took eyelet screws and partly screwed them into the wood - four at each end. Then I made two triangular bridges of card stock. I made four strings from fishing line and tied them to the two sets of eyelet screws. I inserted the bridges under the strings and turned the eyelet screws to tighten the strings. I added colorful ribbon and stars to decorate it. I taught the little ones how to hold a string down to change its note and that the lines are where you press the strings.
Strike a Tune!
For the xylophone, I cut out 2 zig zag patterns out of cardboard 8.5 inches long, and 2 flat ends, one 6 inches long and one 4.5 inches long and fitted the pieces together. I had Malachi paint it and then glued felt to the top once it was dry. Finally, we glued colored pencils, sharpened to size, to the frame. (They made a prettier sound when they were just rested on the frame, but I knew we would lose them.) I made beaters from wooden skewers and beads.
Blow a Horn!
For the horn, I pushed a funnel into 30 inches of plastic tubing. I put tape around the end for a mouthpiece, and looped the hose and added strips of tape to hold and decorate it. I added a cord with tassels for decoration.
Beat Some Drums!
For the drum, I decorated a cookie tin with colored tape, stretched a giant balloon (I used a punch ball) over the tin and taped it. I taped a thick cord with tassels on the opposite sides of the tin for decoration.
For the tom-tom, I took two plastic containers (I used bowls because I could not find plastic flowerpots) and using one, I drew two circles on a piece of muslin. Then I drew two larger circles around each one. I taped the pots together with colored tape. Then I cut out the circles of muslin and cut slits in each edge, as far as the second circle. I folded in and glued the flaps of both circles. Then with a hole punch, I made evenly spaced holes around the edges. I then thread thin cord through the holes and placed a circle over each pot. I then pulled the cord tight and tied it. I zigzagged more cord through the cords at the edges of the circles, pulled it tight and tied it. Then, I was supposed to spread glue over each circle, but I forgot this part! When the glue is dry, the tom-tom is ready! Tightening the cord stretches the muslin and gives the tom-tom a higher note.
These were fun to build and the kids love them! I am hoping to make a song notebook like the one that Carisa has here. Check out her Tools for Tots posts for more Tot Tool ideas!