3. WHAT TO DO
Get the empty bottle
Fill it with vegetable oil
about three quarters full
Fill the rest of the bottle
with water
Add about ten drops of
food colouring
Break the tablet into four
pieces
Add the tablets to the
bottle one by one and
watch what happens
When you have added all
the tablets, put the lid on
the bottle and tilt it from
one side to the other.
4. WHY
Oil and water do not mix, the oil
sits on top of the water.
When you add the Alka Selzer to
the water it starts to make
carbon dioxide, which makes
bubbles.
Because we have added food
colouring, the gas attaches itself
to the colour and makes it move.
When the bubbles reach the top
of the bottle they pop and fall
back down making the colour go
all around the bottle.
