Electro-"Lights"
Orignally: Electrolyte Cars
Created by: Gwendolyn Barr, Ben Matzke, Francisco Santiago
How it works
Cups are placed in the cup holder, and liquids are poured into the cups. A variety of liquids are recommended, a list of which is provided below.
The meter contains a circut, with LEDs showing through on one side. Two wires are left sticking out at the bottom of the meter. When touching a conductive material the circut between these wires will be completed.
Since liquids conduct, they will compete the circut and light up the LEDs. Some liquids are better conductors then others, and will cause more or fewer LEDs to light up. The brightness of each LED will also vary depending on what liquid is being tested.
Reccommended Liquids
- Chocolate Milk
- Distilled water
- Gatorade
- Lemon juice
- Milk
- Orange Juice
- Salt water
- Soda
- Vinegar
- Vegetable Oil
- Water
What Children Learn
On a very basic level, children will learn that liquids carry a current, as well as which liquids conduct better than others. From that, some children may be able to take the thought process a step deeper in wondering what in the liquids makes them more or less conductive. Children may not understand the detailed chemistry behind conduction through liquids, but they should be able to understand the basic idea.
Running electricity through a liquid is probably not something that children have experience with in their every day lives. However, it does have practical, real-life applications. When electricity is run through some liquids, it can change their viscosity. This is commonly used in transmission fluids to reduce wear when changing gears and when running for long periods of continuous use.
From the following list of liquids, children should be able to observe that distilled water is a poor conductor. From that point, the list generally gets better in the following order: water/ soda, gatorade, chocolate milk, milk, lemon juice, orange juice, salt water.
Recreating this Project
We have included some handouts that make recreating this project easier.
How this project happened
Design Task
The task our team was presented with consided of designing, building and testing prototypes of activities that engage students in learning about transfornation of energy. The target audience are the middle school girls who participate in the two-week summer SEE program at Carnegie Mellon.
The project consited of intense brainstorming of ideas about the concepts children could learn about energy and the environment through hands on learning.
The exhibit was supposed to:
- Engage a child's curiosity to learn about energy
- Appeal to all types of children, with differing levels of knowledge and abilities
- Be safe and durable
- Use appropriate and sustainable technology
- Employ principles of universal design
- Consume supplies that can be procured easily and cheaply, or - ideally - materials that can be found for free or recycled within the exhibit
- Include at least one part manufactured by the team
These tasks were met through many iterations of design.
Design Process
The original idea was to build electrolyte cars which taught students the electric properties of fluids by using different liquids to complete a circuit that would power a car. Depending on how long it took the cars to get to the end of the track, they would be able to determine if the liquid was more or less conductive.
We thought that 9V would be enough to power the motor through the liquid. After some tests and experiments, however, we discovered that this was not the case. We had to change the car to LEDs. After observing kids interacting with LEDs at Moving Forth, we changed our project so that it could work.
The meter and the cup holder were cut out of acrylic with a laser cutter. The components were assembled by hand. The final product is designed to be sturdy and kid-prof.