Bubble Trouble by Tom Percival
Rueben and Felix are best friends, and what they like doing best . . . is blowing bubbles - the bigger, the better! It all starts to go wrong when Rueben challenges Felix to a bubble-blowing competition. When they sabotage each other's bubble machines, the results are disastrous. It's time to stop fighting against each other and pull together! A charming story about friendship, fights, and making up.