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SCIPAD - BIG IDEAS - BOOK 1
THE NATURE OF MATTER
Observing Diffusion
Aim: To observe diffusion in a liquid.
Equipment: A petri dish, water, tweezers, 2 crystals of potassium permanganate.
Method: 1. Half fill your petri dish with cold tap water.
2. Place the petri dish on your work bench and allow the water
to become settled.
3. Using the tweezers, place a single crystal of
potassium permanganate in the centre of the
petri dish.
4. Observe for 5 minutes.
5. Repeat the experiment using hot
water.
Observations:
In cold water:
In hot water:
Explanation:
Potassium
permanganate
is poisonous
Behaviour of Matter - Diffusion
When gas particles, such as those in a can of deodorant, are released, they are free to move in
every direction. Eventually, they will spread throughout the entire room.
Scientists call this process ‘diffusion’. Diffusion is defined as the movement of particles from an area
of high concentration to an area of low concentration, until the concentration is equal everywhere.
T
I
M
E
T
I
M
E
Gas particles are
released into a container.
There is a high
concentration of particles
where they were released.
Because the particles are free
to move, the concentration
eventually becomes equal.
Area of low
concentration
Area of high
concentration
1 2 3
Equal
concentration
everywhere
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