This document summarizes a series of experiments conducted by students to learn about the properties of water. The experiments demonstrated that: 1) Water vapor condenses from the air onto cold surfaces; 2) Some materials are absorbent while others are waterproof; 3) Liquid water evaporates into water vapor; 4) Salt lowers the freezing point of water; 5) Hot water is less dense and floats above cold water; 6) Salty water is denser than fresh water; and 7) Adding soap decreases the surface tension of water, allowing for giant bubbles to form. The students found water to be an amazing substance and look forward to continuing their investigation with partners from other schools.

1. CEIP NARCISO ALONSO CORTÉS
VALLADOLID (SPAIN)

2. One of the most
important
substances for all
living things:

3. AFTER A SERIES
OF EXPERIMENTS
WITH WATER WE
HAVE LEARNT
THAT:

4. 1.There are molecules of water in the air
Experiment: Condensation
We put a dry can
in the freezer and,
after 15 minutes,
we took it out and
saw that tiny
drops of water
had appeared on
the surface of
the can.
WHERE DID THE WATER COME FROM?
FROM THE AIR

5. How it works: The
gaseous water molecules
in the air stick to the
cold surface of the can
and they condensate.

6. 2. There are absorbent materials
and waterproof materials
Experiment: Floating flowers
We made water
lily buds out of
paper, then we
put them on
water and little
by little they
bloomed.

7. How it works: When
the paper absorbs
water, it swells and the
molecules of water
push the paper
outwards, so the petals
open.

8. Experiment: Magic Toothpicks
We laid six
toothpicks on
water and
we put a
sugar lump in
the middle,
then the
toothpicks
moved
towards the
sugar lump.

9. How it works: When we put the sugar lump in the middle of
the plate , it absorbs some of the water. A small current of
water flows towards the sugar and pulls the toothpicks with
it.

10. 3. Liquid water can change into
gaseous water
Experiment: Investigating Evaporation
We filled two jars to
the same level of water,
then we covered one of
the jars with a foil
cover.
We left both jars in a
warm place and after
several days , the
uncovered jar had a
lower level of water.

11. How it works: The heat
makes the water
evaporate in both jars,
but the foil cover
stops the molecules of
water escaping into
the air, so the level of
water remains higher
in this jar.
Escaneos
de dibujos

12. 4. Salt lowers the freezing point
of water
Experiment: Lift an ice cube with a toothpick
We lifted an ice cube
with a toothpick by
sprinkling a little salt on
it.

13. How it works: When
you sprinkle salt onto
the ice cube, it makes
the ice around the
toothpick melt. But no
salt falls under the
toothpick and it
becomes frozen into
ice again.

14. 5. Hot water is less dense than
cold water
Experiment: Water Volcano
We lowered a little
bottle full of hot
coloured water into
a big jar full of cold
water, then the
coloured water rose
upwards like a
volcano.

15. How it works:The hot
water is lighter than
the cold water so it
rises and floats to the
top of the jar.

16. 6. Salty water is denser than
fresh water
Experiment: Floating and sinking egg
We put two fresh
eggs into two jars,
one of them full
of fresh water
and the other one
full of salty water
and we saw that
the egg inside
the salty water
floated and the
egg in the fresh
water sunk.

17. How it works: Salty
water is denser than
fresh water, so the
buoyancy on the egg
in salty water is
higher than in fresh
water.

18. 7. We can change water surface
tension
Experiment: Gigantic bubbles
We made
gigantic
bubbles by
adding some
washing-up
liquid to a
little water.
How it works:
The washing up
liquid decreases
the water
surface tension.

19. We think water is an
amazing substance
and we will continue
investigating with
the help of our
Comenius partners.