Interactive music websites suited to primary age.
There's all sorts of fun to be had on interactive music websites which can turn your PC keyboard or mouse into a musical instrument. Some work on a phone/tablet, but some need a computer keyboard. These can be used as part of home-education, or for constructive fun and entertainment! If any of these don't work on your browser, try Chrome instead.
Patatap - very simple, but visually and sonically appealing! Use the keyboard keys to trigger sounds.
Incredibox Beatbox Looper - Animated beatboxers perform whichever samples you choose. Several different soundbanks to choose from, and you can mix by muting some tracks. Great fun!
Launchpad - a version of the iPad app that you can use in a browser. You can also plug in your hardware launchpad if you have one. Top-notch quality and with some practice you can perform like the pro's.
Sampulator - trigger samples with your computer keyboard to create your own performance. You can record your tracks using the built-in sequencer, and save them. Lots of fun, and a great introduction to music production!
Chrome Experiments - Music Lab
(Requires Chrome browser). There are many wild and wacky experiments to choose from. Useful for play and learning.