✩
Temperature and solubility
Background knowledge
It is easier to dissolve soluble substances in warm water than in cold water.
However, heat increases the solubility of some substances more than of others.
Science activity
Make a line graph to plot the data from the table. Be sure to connect all the
points after they are plotted. The data shows the solubility of table salt and
of Epsom salts as temperature increases.
20
30
40
50
60
Amount dissolved
per jug (in grams)
Salt Epsom salts
10
20
12
30
14
40
16
50
18
55
Solubility (g/jug)
Temperature
(˚C)
55
50
45
40
35
30
25
20
15
10
5
0
10
20
30
40
50
60
Temperature (˚C)
1 Do you see a relationship between temperature and the solubility of table
salt? Explain.
2
Is this relationship the same for Epsom salts? Explain.
3 Describe any differences temperature has on the solubility of Epsom salts
as compared to table salt.
Science investigation
Take extra care - ask an adult to supervise you.
You can make rock candy by dissolving a lot of sugar (2 cups) in a cup of boiling
water. Let the solution cool and pour it into plastic cups, filling each half way. Tie
12 cm of plain dental floss in the center of a pencil. Place the pencil over a cup
and let the floss drop into the solution. Repeat for the other cups. Observe what
happens over two weeks. Draw diagrams and explain your observations.
63
© Dorling Kindersley Limited [2010]
63
✩
Temperature and solubility
Background knowledge
It is easier to dissolve soluble substances in warm water than in cold water.
However, heat increases the solubility of some substances more than of others.
Science activity
20
30
40
50
60
0
sa
lts
50
45
40
35
30
25
20
15
10
5
om
Amount dissolved
per jug (in grams)
Salt Epsom salts
10
20
12
30
14
40
16
50
18
55
Ep
s
Temperature
(˚C)
Solubility (g/jug)
Use a line graph to plot the data on the graph. Make sure to connect all the
points after they are plotted. The data shows the solubility of table salt and
of Epsom salts as temperature increases.
55
Salt
10
20
30
40
Temperature (˚C)
50
60
1 Do you see a relationship between temperature and the solubility of table
salt? Explain.
Yes, as the temperature increases, the salt becomes more soluble.
2
Is this relationship the same for Epsom salts? Explain.
Yes, the relationship is the same for Epsom salts.
3 Describe any differences temperature has on the solubility of Epsom salts
as compared to table salt.
The solubility of Epsom salt is more greatly affected by
temperature.
Science investigation
Rock candy is made from a supersaturated sugar solution. Document
candy formation in daily observations and diagrams. Food coloring can be
used to color the candy. Some heat packs are supersaturated solutions
that release heat when crystallizing.
Rock candy is made from a supersaturated sugar
© Dorling
Kindersley
Limited [2010] in daily
solution. Document
candy
formation
observations and diagrams. Food coloring can be used