Return to Mathematics IndexMeasurement of Volume

Richard Murray Gage Park High School

5630 South Rockwell

Chicago IL 60629

(312) 535-9230Objectives:

This mini teach is for middle school and high school students. It can be

adapted for younger children as a demo.

Students will be able to measure the volume of a clear container. Students will

be able to use a stop watch. Students will be able to estimate the volume of a

container using proportions.Materials Needed:

Clear jars, glass or plastic, enough of them so that every group of students

will have two containers to measure. Enough sand to fill the largest container.

Measuring bowl and cup marked in milliliters; candles and matches; stop watches

for each group.Strategy:

What was expected was a linear relationship between the burning of oxygen in the

jar and volume of air that it contained. If it is linear it will be

predictable. Knowing how long it takes to extinguish a candle for a certain

volume you should be able to predict either the volume and or the time to

extinguish a candle for another container.

The students will time how long a candle will stay lit when a jar is placed over

the candle. The student will measure the volume of the jar by filling it with

sand and using the measuring bowl or cup to find out how much sand is in the jar

in terms of the metric system.

Students will then time how long a candle will stay lit in a much larger

container. Knowing the previous data regarding volume and time and now knowing

the time for this new jar the student should now be able to predict the volume

of the second jar. The prediction is developed through proportions. The ratios

that make up the proportion are: volume is to time as second volume is to second

time. Restating the problem, the proportion will look like:volume in ml/timeto extinguish the candle = unknown volume of the new jar/time to extinguish thesecond candle.

Solving the proportion the student will have the predicted volume. To verify

the prediction the student will measure the volume of the second container using

sand. The student will determine how close the prediction is to the actual

measurement.Performance Assessment:

The linear relationship that was expected was not produced by this procedure.

It was not established that there is linear relationship. The predictions for

the larger jar were off. If the time was measured for the larger jar then

predicted volume was larger then the actual measured volume. If the volume of

the larger container was measured then the predicted time differed greatly from

the actual time.

Sources of error are pressing the stop watch (timing errors), the candle is not

burning at a constant rate, a larger flame burns oxygen at a greater rate;

errors using the measurement bowl; the jars need time to refill with oxygen, if

you try to repeat the timing of the burning candle too soon the results will

vary as much as 4 to 5 seconds.

It was a good lesson in measuring, timing and gathering data. But it did not

support the hypothesis. Because the hypothesis is not supported then it creates

a problem for the students. The expectation is that the goal should be achieve

and it wasn't. This is a problem that will need to be addressed with the

students.

Things that could be tried to improve the results are: work with larger volumes

such as storage cases instead of jars; the candle be replaced with a source that

burns consistently such as of oil with a wick.