Réalisation - Spirometer

Etape 1

Cut the top end of the bottle to form a funnel.

With the punch, drills a hole in the center of the cap.

Etape 2

Insert the top of a straw through the cap.

Cut the straw to leave approx. 10 cm outside.

Etape 3

tape another straw on the side of the funnel.

Etape 4

Cut a peace of 20 cm from the third straw.

Fold it in half and surround the vertical straw.

With adhesive tape, fix the two folded ends together .

Etape 5

Using aluminium foil, form a very light ball (not very compact).

The ball has to be the size of a large nut and well rounded.

Place it in the funnel.