A CIESE Collaborative Project

Fall 1998 Student Reports

Edison Intermediate School

Westfield, New Jersey, USA

The problem being investigated was Does elevation, volume of water, temperature of room, or the heating device effect the boiling point of distilled water? Different groups in our classes had different hypotheses. Some groups hypothesized as elevation rises, the lower the boiling point will be because the higher the elevation the thinner the air. Some groups hypothesized that as the room temperature rises, the boiling point of the distilled water will also rise. And other groups hypothesized as the volume of water increases, the boiling point of distilled water will increase. We ran this experiment for three days to account for any differences in the atmospheric conditions. We learned that the relationship between air pressure and boiling point of water is that when you boil water the pressure outside will squash those bubbles. When the water starts to boil there are tiny bubbles that don't have enough pressure inside them to stand up to the outside air pressure. The outside air pressure pops the bubbles. Soon there is enough heat and as more energy goes into the bubbles, they will get bigger and be able to stand up the outside air pressure.

When we analyzed the data, we noticed that there was a strong relationship between the boiling point of water vs. elevation. This graph showed a negative correlation that indicates that the higher the elevation the lower the boiling point. For example, data submitted from schools at a lower elevation than ours they had a higher boiling point and at a higher elevation had a lower boiling point.

As a group we learned that elevation is the variable that most changes the boiling point of the water. There are a number of schools that share this data such as 1,200 ft. elevation : 98.7 C boiling point; 1,000 ft. : 99 C boiling point; 126 ft. elevation : 101.7 C. and the boiling point vs. elevation scatter plot graph showed a negative correlation which supports our conclusion. In conclusion, we have determined that as the elevation increases, the boiling point of the water decreases. We learned a lot from this project and enjoyed participating in this activity.

Combined efforts from Miss Leparulo's and Mrs. Squillace's 6th grade science classes Tara O., Lindsay D., Cameron W., Josh N., Amanda D.,Camille H., Rachel I., Dan J. Dina R. Gavin T. Brett P. Kayli S., Lisa Z. Brad, Elsa P., Judy,

Moscow School 1636

Albina, Russia

First we took the water we usually use at home and boiled it. And you see - it boiled At 102 C ! We asked our teacher, why wasn't it boiling at 100 C as we learned, and she told us a lot of interesting things about the salts dissolved in water. We found out that the more salts contains the water the higher is its boiling temperature.

Then we boiled water at the low pressure. First we made the pressure as low as it was possible and then made it higher and higher until it became normal atmosphere (that day it was 750 mm).

Here are our results:

 Pressure (mm) 100 150 250 500 750 Temperature (C) 53 61 73 90 102

We were very glad to take part in the project. Thank you for your kind attention. We hope it is not the last time we contact.

With best wishes also for coming Christmas

Pupils of Moscow school 1636, Albina .Russia.

Eastlake High School

Redmond, Washington, USA

As students of chemistry, we know that the boiling point of a liquid is the temperature at which the vapor pressure of a liquid equals the atmospheric pressure. While we were gathering our data for this project we were studying the behavior of gases, and more specifically gas pressure. In our lab experiments we used the current barometric pressure readings. The atmospheric pressure was one data item that was not reported. Since we live in a rainy area, and we know that low pressure accompanies stormy weather, we wonder if that had some effect on our results. We would have liked to be able to compare boiling point to atmospheric pressure at the time the data was gathered.

We know that the more air there is, the more force it can exert on the surface of the earth, and hence the greater the atmospheric pressure. As the elevation increases, the amount of air decreases. We would expect that at higher elevations, the atmospheric pressure would be less. If the atmospheric pressure is less, then the vapor pressure of the water required for it to boil would be less. Looking at the results, it appears that at much higher elevation..5000+ feet, the boiling point is substantially lower than the result close to sea level. Closer to sea level however, there seemed to be much variation in the results that could not be explained quantitatively by elevation. Checking the values of vapor pressure of water for various temperatures, at 70.1 kPa, water boils at 90 degrees Celsius and at 101.3 kPa water boils at 100 degrees Celsius. The difference in pressure required to observe a substantial change in boiling point is quite large. This provides an explanation for why only the very high altitudes gave a clearly lower temperature.

We found that even in our own classroom, values varied from 99 to 101.5 Celsius. As we looked at the different sources of heat and results from different grade levels, we concluded that lab technique was a major factor. The flame of the bunsen burner is extremely hot and if the thermometer was resting on the bottom of the beaker, it could heat the mercury directly and the temperature of the boiling water would be artificially high. Depending on where the flame was in contact with the beaker and location of the thermometer, results could vary. We also did not calibrate the thermometers. We discussed the importance of standardized instruments when sharing results with the scientific community.

Overall we enjoyed participating in this project. We discovered that even though it seemed trivial to "just boil water" we learned some things about pressure, lab technique and collaboration.

Mrs. Clayton's Chemsitry Classes

Hamilton High School

Anza, California, USA

Our original hypothesis was that the boiling point would be directly proportional to the amount of water used. After looking over the submitted data we noticed a relationship between the boiling point and elevation. The lower the elevation the higher(or closer to 100) the boiling point. We are at 4000 ft (relatively high) and our results were 94.5 degrees, relatively low. In conclusion, of the variables given, the variable most affecting the boiling point is elevation.

Notre Dame High School for Girls

Chicago, Illinois, USA

Questions

1) Boiling point differs from location to location because of factors such as elevation, latitude, and longitude.

2) We will submit the average value because each lab pair got different results and in some way we need to come to a class result which would be the average value. Accuracy is very important because we want to be as close to the answer as possible so we are aware if we're doing the experiment the correct way.

3) The class average was below the expected value (the boiling point = 100 degrees Celcius). Our class average was 96.37 degress Celcius which was a discrepancy because it's not accurate.

4) The boiling point at the Rocky Mountains would be higher because the air is thinner and the elevation is higher. The higher the elevation, the longer it takes for a liquid to boil.

Submitted by: Mary Orosa and Sr. Maureen Fallon
Notre Dame High School for Girls
Chicago, Illinois

St. Paul Elementary School

Our class found that the elevation had the greatest effect on the boiling point. The highest elevation had the lowest boiling point. We decided that accuracy was essential to make this project work. Some of the things you had to be accurate with were the amount of water (had to be measured the same for each group), the temperature could have been taken at more accurate intervals and the room temperature should stay the same. We decided that the next time we did the experiment we would use the correct water. We used mineral water instead of distilled water which through our boiling point off. That's about it from Stoney Creek Ontario.

Plovdiv, Bulgaria

To 13-18 years-old students from The Mathematical Secondary School "Academician Kiril Popov" in Plovdiv conducted the experiment . In the course of three days the students measured the temperature of the Boiling Point .The measurements are showed in charts and tables . There were three groups of student who worked individually and they gathered their results.

We reached these conclusions :

1. The elevation is the factor which shows the strongest correlation to boiling point.

2. Other factors like : room temperature , volume and heating devices do not show much correlation to boiling point.

3. When the water boils there are bubbles which are rising from the bottom of the pot . The pressure is the most important factor which has influence on the bubbles and because of the close bond between the elevation and the pressure the elevation is the most important factor of boiling point.

4. If we pick a location where the elevation is higher than our location we will predict the pressure will be lower and because of that the boiling point will be lower.