Science Buddies: "Ask an Expert"

My daughter is in the 6th grade and is doing a project on growing borax crystals.

We are trying to figure out how we should measure these crystals to see which conditions grow the "best". I thought about getting a digital scale that would weigh in grams but that is rather expensive (around $30.00) for something we will never use again.

I am worried that using a ruler or tape measure will not give detailed/accurate enough results.

Any suggestions?

Hi,

It always makes me feel good when parents get involved with their childrens' science projects. Congratulations of your participation!

I believe the experiment you're daughter is running will show fairly significant differences in the crystal growth rate at the various temperatures. She will be able to see it fairly easily.

One way to "measure" things in science is subjectively, rather than objectively. Rather than use a ruler or a scale, your daughter could assign a subjectively assigned number value to the size of crystals. This is how gymnastics and diving events are scored.

A most important scientific concept to follow is to ensure that each experiment is repeated multiple times. Often, random variation can create a large effect on scientific outcomes. So performing multiple runs of the experiment, and carefully scoring each run using a well defined, but subjective, scoring system, will yield satisfactory results.

Good luck and HAVE FUN!

If you have a digital camera, you could place a ruler along with a card documenting the test conditions on a table along with each container of crystals. Having the pictures with a scale does an excellent job of documenting your results for use in the project write up.