An experiment to pop balloons using a laser pointer pen
Black Marker Pen
Laser Pointer Pen
Blow up a bunch of black and white balloons - at least 1 black one for each cub and a handful of white.
Use the Sellotape to attach a black and a white balloon to a table so that the balloons stay in place.
*For safety reasons: ensure that the table with the balloons attached is at one end of the room, and all the people are at the other end; make sure that the laser pointer is only directed at the end of the room where the balloons are, and never towards a persons face - for this reason I suggest only having 1 laser pen, with a leader in charge of it, and just passing it to a single fully supervised cub at a time; at any point when there is someone at the end of the room where the balloons are the laser pointer must be in a leaders possession to ensure it is not accidentally switched on.*
First aim the laser pointer at the Black Balloon - it may be best to rest the pointer on a table, perhaps with some blu-tack or similar to help aim and keep it steady.
The Black Balloon will pop when the laser is pointed at it.
Next aim the laser pointer at the White Balloon.
The White Balloon will not pop, despite having the laser pointed at it.
The Black Balloon pops because the black colour absorbs the heat from the laser, causing the balloon to 'burn' a hole into it.
The White Balloon does not pop as white is not a colour which absorbs heat as easily.
In order to demonstrate that this is the case, next draw a large black dot onto the white balloon, and aim the laser at this dot - the balloon will pop.
This is a good example of why many people from Desert regions wear light coloured clothing, as it reflects, rather than absorbs, the majority of the heat from the sun.
In addition you could use this as a challenge, to see who can pop a balloon with the smallest black dot on it, to test their marksmanship skills!