Our second science experiment involved a balloon. We blew it up and tied a  knot at the top.

 Will it pop?

 Mrs Buckley pushed a skewer into the top of the balloon.

Will it pop?

 Oh the suspense!

 Now the skewer is pushed through the other end of the ballon. The thick part.

 Hey Presto! Why didn't the balloon pop?

 Mrs Mills poured some coloured water into a plastic bag.

 Then she pushed a skewer through the plastic.

 Why didn't the water come out?