Did you ever want to play a musical instrument but just couldn't afford one ?
Worry not because we are going to show you how to make a 'double bass' out of old bits of junk.
One of the problems of being a grandpa is that things change quite a bit so I don't know if you can still buy old Tea Chests.
Just in case you can't I have designed my Tea Chest Bass on a styrene fruit or fish box. Those I know you can get.
You will need a box, a piece of dowel about one and a half metres or more long (depending on just how big you are) and some chord or rope.
On the base of the box, with the open bit on the floor and dig out a little grove that your dowel can sit in so that it does not slip.

This should be in the centre of the narrow bit and near the end lengthwise.
At the centre, about three quarters of the way along the box, make a hole for your rope to go through. Pull the rope through a little and tie it to a stick on the inside of the box and fasten the other end to the dowel near the top and long enough that the dowel almost stands up straight when it sits in its special groove.
Now, put your foot on the box to hold it steady, pull the dowel back so that it is just tight and pluck the string. Pull a bit more and pluck the rope and you will notice that the sound has changed.
With a bit of practice you will be able to make a whole range of sounds that you can turn into music just like the real thing.