Blow round the glass - You can demonstrate that air streams do not always travel in straight lines, but will follow round the shape of obstacles. You may have seen wind flow patterns of smoke around prototype cars in wind tunnels. These show designers how good the streamlining is.

Figure 8 - Blowing round the glass

Ask your pupils if it is possible to blow out a candle when there is an obstacle in the way? This is a quick and easy activity to show your breath must travel round the sides of the glass (or tin of soup etc). Just blow straight ahead and the candle will go out.

  Bubble & fizz