Download Contents Required - Harrowbarrow School

By Jennifer Francey
Contents Required
1 x Large deep round bowl
1 x Small Square bowl
3 x Coins
Table Salt
Food Colouring
Tray of ice
Cling film
Scissors
Hot water
Kitchen roll for cleaning up
Step 1
The first step of the experiment was to
fill the bottom of a large mixing bowl
with hot water. The water is used as a
representation of the sea as we have
here on earth.
Sea water in Tahiti
Step 2
The next step was to add some food
colouring to the water to make it look
even more like sea water. This would
also help with the experiment to show
the difference between our sea water
and the rain water collected should
the experiment be successful.
The food colouring used, belonged to
my Nannies father, my Great Granddad
who unfortunately I never met, but it
means the colouring may be 50+ years
old at least.
Step 3
Again the addition of some table salt
ensures the sea waters authenticity as
well as providing us with a difference
between the sea and rain water.
Harvesting sea salt
Step 4
Next, I placed a square bowl in the
centre of my larger bowl. This was to
be used as my collection bowl for the
rain water that fell.
Step 5
Using cling film and stretching it tightly
across the top of my bowl, I created a
tight seal ensuring that none of the
warm air rising could escape.
Planet earth has an atmosphere and
an ozone layer. Like the cling film used
here, earths atmosphere creates a
barrier from solar flairs and acts as a
ceiling containing our clouds which are
formed when warm air rising meets
the colder upper atmosphere.
Step 6
Using plenty of ice and placing it on
top of the cling film, we created the
colder upper atmosphere. By doing
this, it gives a visible contact area
between the warm and cold layers and
we can then see the water forming on
the underside of the cling film.
In the natural world this can‘t usually
be seen as it happens up in the clouds.
Clouds are formed when warm air
coming off the land or sea rises and
meets the cooler air from either of the
two poles or the cold upper air in our
atmosphere.
Step 7
The melt down!! From the close up
photograph we can clearly see how
water (rain) droplets have started to
form to the underside of the cling film.
Step 8
After some 45 minutes we have totally
melted the ice and again water (rain)
droplets can be seen on the underside
of the cling film. The coins help to
centralise the rain droplets into our
smaller bowl. This is pretty much what
happens in the clouds above us!! The
water droplets slowly get larger and
larger until the cloud can no longer
support their weight and this is when
the water starts to fall from the cloud
which we call rain.
Step 9
It’s raining…..
Not the clearest of pictures, but we
can see a drop of rain water just about
to fall as it gets too heavy to be
supported.
Step 10
The results are in!!!
After carefully removing all the melted
ice from on top of the cling film along
with the coins, I then took off the cling
film to see how much rain water had
been collected. In total I left the
experiment for 45 minutes to an hour
until all my ice had melted , this gave
more reaction time between the hot
and cold temperatures and gave me
more rain fall the results of which can
be seen in the corner of my yellow
bowl.