A CIESE Collaborative Project

Fall 1999 Student Reports

Wahama High School

Wahama Jr./Sr. High School, West Virginia, USA

We are 8th graders from an integrated science class at Wahama Jr./Sr. High School in Mason County West
Virginia. The boiling point of water is the point at which water changes from a liquid to a gas.

We started this project to learn the variable that determines when water boils. We learned that elevation was the factor that determined the boiling point.

We did this project by putting 500 ML of ice water in a beaker and heating it on a hotplate. We measured the
temperature of the water with a thermometer.

Our hypothesis was that the higher the elevation the lower the boiling point. Our elevation is 600 ft. above sea
level, and our boiling point was 98 degrees Celsius. We learned that the higher up you are the lower the
pressure. Where there is low pressure the water bubbles rise faster causing it to boil at a lower temperature.

In conclusion we learned a lot of things about density, which is mass per unit of volume, and pressure, which is
force per unit of area. We also learned that elevation affects the boiling point, because the higher the elevation
the lower the pressure and therefor the lower the biling point.

Here are some examples that support our hypothesis:

elevation temperature

4,000 95.3

1,995 96.4

600 98

330 99.9

217 100

65 101

We really enjoy doing hands on projects that teach us concepts that we learn easier through touch and see
rather than reading it in a book.

 

Bettendorf Middle School

Bettendorf, Iowa, USA

CONCLUSION & SUMMATION OF BOILING POINT ACTIVITY

Different groups of students posed different problems for this project. The common factor was the interest in
what affected the boiling temp. more. These were some of the factors that students considered while boiling
water: changes in air temp., changes in air pressure, tools used to collect data. Students all used hot plates as
the energy source. Water was boiled on 3 separate days over a two-week period. This allowed students to take
advantage of changing weather conditions such as temp and pressure to see if they had any effect on the
results. Two different methods of data collection were also used. Alcohol filled thermometers and Vierner
Temperature probeware for the computer and the LoggerPro computer program for data collection. Over the
three days that students boiled water they discovered that there was very little variation in the results that they
recorded on a given day. However, the condition that affected the temperature at which the water boiled was the air pressure. The day we have a very big long drawn out storm the water boiled at a much lower temperature overall compared to the other two days. On this day the air pressure was much lower than normal. The temperature variations during the two 'normal' days were within an acceptable range from between 99.83 - 101.96. Students were in general agreement that using the computers was not only more fun but probably more accurate as it took out the human factor for reading the thermometers inaccurately. A culminating discussion ended up with students trying to find ways to eliminate skill errors in performing the experiment. After comparing the posted temperatures of boiling water from different geographical locations, students reached the conclusion that perhaps there was a correlation between altitude and air pressure. One observation/question was asked: Is there some connection to the reason for different cooking directions on some foods, due to differences in altitude? Other questions followed. Q: Does altitude/air pressure differences affect all cooking times? I guess we have more inquiries to do.

 

Beatrice Rafferty School

Perry, Maine, USA

The Beatrice Rafferty School eighth grade science class arrived at the conclusion that the variable that effected
the boiling point most was elevation. It took several tries and approaches, but we finally singled out one variable
at a time and arranged them from lowest elevation to the highest. In this order we could begin to see a pattern,
with only a couple of "odd" readings, developing. The pattern we saw was that the at the lower elevations, the
boiling point was higher and as the elevation increased, the boiling point went down. For example, the boiling
point at sealevel was 98 (our own boiling point was figured to be 98.9 at sealevel), while at an elevation of over
7,000 feet, the boiling point was 91.

Our original hypothesis was not correct. We, at first, gave no consideration to elevation. We did find that when
we were trying to figure out, from the data, the most effecting variable that we got caught on time. Several times we based a conclusion on time, but had to come back to find only the number. Our class learned that there is a lot to research and data analysis. It's easier to just guess. Next time I think we should do more boiling in our
class. If we found that 250, 350, and 500 mLs of water boiled at the same point as our 700 mL, then we could
have figured that it wasn't the water volume and so on.

 

Georgetown Middle/High School

Georgetown, Massachusetts, USA

Students in the 9th Grade Physical Science Courses conducted this experiment and analyzed the results using
Microsoft Excel. Data was tabulated, averaged and graphed for their own class's results and these results were
combined with the Project's checked data set. Graphs were made of the results and students came to the
conclusion that the only graph demonstrating a significant pattern was that comparing boiling point to elevation.
There was some surprise in class as to these results, but then some students remembered how long it took to
cook pasta when they were hiking with their families in mountainous areas. They now have to spend time in the
media center finding out the scientific basis of the relationship between elevation and boiling point. Students
discussed the existence of aberrant points and the concept of variation in data sets. The importance of
replicates, averages and large data sets was discussed previously in class and this project truly helped students
to understand these concepts.

 

Fifth Street Middle School

Bangor, Maine, USA

Fifth Street Middle School is located in Bangor, Maine (68 46' W., 44 48" N.) at an elevation of 168 feet.

There is a definite negative correlation between boiling point and elevation as shown by the linear trendline on the scatter plot graph for these two factors. The trendline sloped down very obviously with the dots following the
trendline. For the most part, the higher your elevation, the lower your boiling point. The data for the other two
factors, room temperature and water volume, are too random for a line of best fit.

Right now, we do not know how to determine the equation of the line. When we come to that in our Algebra
book, we¹ll try to do this.

Our classes had thought that elevation would affect the boiling point the most, and it obviously did. It makes
sense that elevation affects the boiling point because we already learned that things take longer to cook in
Denver than here in Maine, and that¹s sort of the same thing. We think air pressure causes this.

It is very important to have accurate measurements, as it is in all of science, so that results are accurate. A
degree is a lot in this experiment, and may make the overall conclusions wrong. There¹s a possibility that the
thermometers we used might not have shown the correct results; we were using student thermometers. If the
wooden popsicle stick was pushed down too much, it might have affected the temperature reading. Also, we
were using hot plates that would switch off when we used them. Also, a school may not have known its exact
elevation and had to estimate.

If we were to repeat the experiment, we would need much more accurate thermometers. Other variables we
could test would be: air pressure, humidity, or air quality.

All, in all, we liked the experiment the way it was. It was neat to see the results from all over the world and we
thought everything was well done.

 

Drake Middle School

Arvada, Colorado, USA

Students in our eighth grade class boiled water using several methods and amounts. We reported on our results with
our most common method, but the results did not vary due to the different methods used.

Most of us thought that elevation would have the greatest effect, since we live next to the Rocky Mountains and have
observed differences when we visit the mountains and cook there. When we graphed our data and the data from other locations, there was a trend that mostly indicated a decrease in boiling point temperature when elevation increased. Our Introductory Physical Science textbook describes this as being related to air pressure.

Our other graphs appeared to have no clear trend. We would like to see more schools participate at higher elevations
and hope to have better facilities when we move into our remodeled classroom in the spring.

 

B. H. Wood School

Plainville, Massachusetts, USA

K.S.: In class we did an experiment called "Boil, boil, toil, and trouble". In this experiment we boiled water and
recorded at what temperature it boils. Then we submitted our information to the website to be published.

Based on the data that we collected from the website I came to a conclusion. My problem was which affects the
boiling point most: the volume of water, the elevation, or the room temperature.

My conclusion is that elevation affects it the most. I think this is because the air is thinner at higher elevations,
therefore, the higher the elevation, the lower the boiling point.

S.C.: The higher the evelvation, the lower the boiling point because at higher elevation that's when the air is thin so the
moleclues spread out, but at lower elevations the molecules are packed in.

 

Central Middle School

Stirling, New Jersey, USA

Upon completing the International Boiling Point Project, our class came to the following conclusion:

Elevation seems to have the greatest effect on boiling point because as the elevations of the locations increased, the
boiling points decreased. We think that this is due to the decrease in air pressure as one move to a point of higher
elevation. Since there is less atmosphere at higher elevations, there is less pressure on the surface of the water
making it easier for the liquid water to escape to the vapor phase.

Finally, our class debated what caused the scattering of points at similar elevations. It seems to us that it may have
been valuable to measure the barometric pressure each time the experiment was conducted in order to determine if
that had any effect on the results.

Thank you for the opportunity to participate in this program. We had a great time. We felt that we learned alot and it has opened our minds to asking new questions about boiling point.

 

Sarah Scott Middle School

Terre Haute, Indiana, USA

We found that elevation played a big factor in the boiling point. As elevation increased the boiling point decreased. I
feel if we did this project again we would have to calibrate our thermometers to be more accurate. Our class said room temperature would effect the boiling point but we found out otherwise. Thank you for allowing us to participate in this project.