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Salt in Boiling Water. By John-Paul Evans. Purpose. What does ice do to hot boiling salt water and why does it do it?. Hypothesis . Ice in measuring cups causes salt water to cool slower than ice in measuring cups without salt. . Interesting Facts. - PowerPoint PPT Presentation
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Salt in Boiling Water
By John-Paul Evans
Purpose
What does ice do to hot boiling salt water and why does it do it?
Hypothesis Ice in measuring cups causes salt water to cool slower than ice in measuring cups without salt.
Interesting FactsFirst, heat does not flow from hot to cold.Second, salt water freezes 30 to 40 degreesThird, hot water freezes faster than cold water.Fourth, boiling water and adding salt takes longer to boil.Fifth, adding salt to water raises its boiling point.
Experiment
MaterialsPot of water
Hot Plate
Salt
Several Ice Cubes
Watch with Minute Hand
Pencil and Paper
Two Thermometers
Two Glass Measuring Cups
Tablespoon
Graph Paper
ProcedureSet pot of water on hot plate and turn on hot plate until water boils. Ask mom or dad to help with this step.
Put two ice cubes in each measuring cup.
Put a thermometer in each cup.
Put two tablespoons of salt in one measuring cup.
Once water comes to a steady boil pure one half a cup of water in each cup.
Observe what happens to the boiling water.
Take temperature reading from the thermometer every ten seconds. Have mom or dad help time the ten second intervals.
Record temperature change each ten seconds in each cup.
Plot a table of temperatures of each cup using one axes and time of the other.
DataTime Temp of water w/o
saltTemp of water with salt
10 seconds 50 C 51 C
20 seconds 50 C 50 C
30 seconds 49 C 50 C
40 seconds 48 C 50 C
50 seconds 48 C 50 C
60 seconds 50 C 50 C
70 seconds 50 C 49 C
80 seconds 49 C 49 C
90 seconds 48 C 49 C
100 seconds 49 C 49 C
110 seconds 48 C 47 C
Analysis of Data and Observations
The data seems to show
water with salt cools
more slowly than water
without salt.
AnalysisBoiling water stopped and start cooling immediately.
Temperatures and times show water cooling at different rates in each cup.
Salt water cooled slower in ice than water without salt in ice.
Did the experiment test your hypothesis? Yes
How do you know? Because the data tells me so.
ConclusionWas your hypothesis correct? Yes What would you change in the experiment and why? I would add more salt to see if I could slow cooling.What are some new questions you have?
New Questions to Research
Can more salt slow water cooling?
Can more ice change the cooling of salt water?
