Overview and Background

This probe allows for a hands on exploration of electricity and conductivity.

Lesson Plan and Activity

Exploring Electricity with a Conductivity Probe

What is a conductivity probe? A conductivity probe is used to measure whether something is conductive and when connected to the proper measurement tools, how conductive it is. This probe is a very basic probe that measures whether an object is sufficiently conductive for electricity to get through it to turn on the LED. The LED will turn on when there are sufficient ions in the liquid to conduct electricity.

Conductivity Probe Lab
With the conductivity probe built, students can now perform a lab to explore conductivity in more depth. It is suggested that the lab be designed around a theme. Suggested themes include:

Comparing food: Use the conductivity probe to explore how conductive different common liquids are. Prepare a glass of different beverages (juices, soda, sugar free soda, low calorie beverages, sport drinks, tap water, filtered water) Which beverages make the LED light up? Which ones do not. What conclusions can they draw based on their data?

Use the probe to compare different beverages for conductivity. What makes the LED light up the brightest?

Food Science

Explore how different titrations influence the conductivity of a liquid. Prepare samples with different levels of concentration of basic cooking materials (sugar, salt, flour, baking soda…) Using the probe, how does the conductivity change based on the material used?
What do we think that means about the relative conductivity of the food objects?

How does adding salt, sugar, baking soda... common household materials impact the conductivity of water? Why?

Environmental Engineering

Lets understand the differences in the water around us: Is tap water conductive, is pond water conductive, is bay water conductive? A common test for water quality is dissolved solids which measures conductivity. Dissolved solids are measured in Parts Per Million (ppm) How accurate is this probe for measuring dissolved solids?

Soil analysis Is different soil more conductive than others? Prepare numerous pots with different types of soil (topsoil, playground sand, beach sand, mulch). Are they conductive when dry? What happens when water is added? How much water is needed to make the soil conductive? What does that say about the differences in the soils?

How much water is needed to make soil conductive? Why does soil become conductive?

Materials Needed

Materials Needed

Copper Tape
Lectrify Components (http://lectrify.it)

Skills Learned

electricity
conductivity
transfer of energy
engineering design
engineering
engineering process
env. engineering

$2 Conductivity Probe

$2 Conductivity Probe

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