1.) Place your items
of on a table at the front of the
room. If you are going to use a fan
place it at the front of the room
with you so that the air blows towards
2.) Have your helpers
form a line at the front of the room.
Then ask each volunteer to (excluding
the first person in the line) take
one step backwards to form a bit of
a gap between each of them.
3.) Ask your helpers
to place their blind fold on or ask
them to keep their eyes closed.
4.) Leave the fan
switched off. Ask your helpers to
raise their hand if/when they smell
something different in the air.
5.) Open the lid or
spray one of your items and see how
long it takes for the aroma to reach
each of your helpers. You could record
your results by using a stop clock
to see how long it takes for each
smell to reach each person. One test
could be with the fan off and the
other could be with the switched fan
If you choose to use a basil
plant in your experiment it is probably
best if you hold the plant and walk
past each person in the line.
As you get close to each
person place one hand on the top leaves
of the plant and just fan them slightly
with your hand to help the aroma to
move through the air. It is amazing
how powerful a basil plant can smell.
This experiment is about
diffusion. What is diffusion?
Diffusion happens when particles
mix with each other without anything
Smells move around a room
and some end up in our nose where
we have smell detectors (our sense
Gas particles move on their
own in the air and therefore the smells
mix and spread. With the use of a
fan the smells move through the air
Diffusion happens in liquids
as well but it takes a bit longer
for diffusion to occur in liquids.