EKF :: Ku’ula 7-9 Curriculum

Phase 5 : The Experiment

Identifying The Variables

A variable is the “thing” that is being tested in the experiment. There are two different variables. The independent variable is the variable that is not affected in the experiment. The dependent variable is the variable that is affected in the experiment. In other words, the dependent variable depends on or is affected by the independent variable. This may be confusing for the students so reserve a fair amount of time to go over variables. Again you can use sample science fair topics as examples before having them identify the variables in their own experiment.

Examples :

Comparing the amount of green sea turtles at Punalu‘u Beach and Keauhou Beach.
Independent variable = location

Dependent variable = the amount of green sea turtles

Reasoning : The locations (Punalu‘u and Keauhou) do not depend on the number of turtles found at each location. Punalu‘u will always be Punalu‘u and Keauhou will always be Keauhou. The number of turtles found does depend on the location and the conditions of each location. A location with more limu available will attract more turtles.
The effect of salinity on the growth of limu.
Independent variable = water salinity

Dependent variable = limu growth

Reasoning : The amount of salt in the water is not at all affected by the limu. Salinity will not all of a sudden change because limu has been in contact with the water. The limu on the other hand is affected by the water's salinity. If there is not enough salt in the water the limu's growth will most likely not progress as well.

Creating Data Tables

Before you let the students begin their experiment, help them create a data table that they will use to record their data. Most students have used data tables in math, but mainly just to pull information from them. Most students have not had to make their own data table from scratch. Just as you did with the hypothesis, take students through the steps of creating data tables for sample science fair projects before they tackle their own project.

Data Tables Notes

Use the creating data tables worksheet to give students experience in creating their own data tables. Go through the first example as a class then let them try the other problems on their own. This worksheet can also be used in the data analysis phase where students graph their results. If you plan on doing just that, make sure students don't lose their worksheet.

Creating Data Tables Worksheet

Once the students have completed the worksheet, have them create a data table draft for their own experiment. They may need only one draft before doing their final data table. They will use that final to record their data during their experiment. Stress the importance of not losing the data table. If the data is lost, they will have to re-do the entire experiment.

Conducting The Experiment

Give students at least two weeks to conduct their experiment. If you are doing this project during the second semester, spring break is a good time for the students to conduct their experiment. As long as the students have a solid experimental design to work from, they should be ready to conduct the experiment on their own but give them a few reminders:

Make sure the student is conducting the experiment and not your family.
Gather and prepare all the necessary materials before starting.
Start early to leave some back-up time in case you need to re-do the experiment.
Leave your experiment in a safe place where outside variables (wind, rain, pets, younger siblings, etc.) won't affect the experiment.
Record results accurately and timely. It's easy to forget to measure something especially if you're doing it on a daily basis.
Take pictures during your experiment for the display board