Spread the Smell
Steps:
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 you participants.
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 on.
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 moving them. Smells move around a room and some end
up in our nose where we have smell detectors (our sense of smell).
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 faster.
Diffusion happens in liquids as well but it takes
a bit longer for diffusion to occur in liquids.