Electric Slime for Colorful Afternoons

What you'll learn:

How to make and use conductive, or electric, slime.

Key takeaways:

We can visualize resistances using a color changing LED.

This is a fun science project to do in March to bring the magic of Leprechauns and rainbows into your house, but it is far more than just a St. Patty's Day science project. This activity will captivate kids in an afternoon of learning, and is a great doorway into a very cool science fair project. 

The electric conductive slime uses our base clear slime with no add ins - can you think of why regular clear slime would be conductive? Can you think of additional ingredients you could add in to try to increase, or decrease the conductivity of this slime? Sounds like another interesting science fair project with slime if you ask me. In fact, at the bottom of this post I will include some ideas on how to turn this electric afternoon into a science fair project if you are so inclined.

Project Ingredients:
Clear slime
RGB LED (these ones are pricier but a lot larger and more fun for littler hands)
9V battery (you can get 2 for $1 at the dollar store)
9V battery cap

How to make conductive slime.

using clear slime to light up LEDs - DIY Conductive slime

1. Mix up a batch of clear slime.

The first time I tried this electric slime project we made two batches of slime, one was clear slime with PVA glue, and one was basic slime, with white glue. While the white glue still conducted electricity, the RGB LED was not as bright, and the color mixing was not as bold. 

What makes this slime electrically conductive? Ions in water. Water in it’s most pure form is actually a great insulator, however, the water containing ions like salt is a great conductor. That is because ions or charged particles are great conductors, and water is a fantastic ionizer. Food for thought if you are thinking about things to add in to  your slime to make it more (or less) conductive.

DIY conductive slime for fun electric slime circuits

2. Connect your LED to the slime

Safety first! NEVER hook up an LED straight to a 9V battery. So much voltage can cause some LEDs to explode. Usually, you would make a series circuit (or a circle) of a resistor to LED to battery back to the resistor. Can you figure out what our resistor is in this case?

Your RGB LED has four legs. one leg each for red, green, and blue, and one for the common cathode (positive) or cathode (negative). You can identify the special non-color producing LED leg by looking for the longest leg of the four. That is your special leg. Making note of the leg make your leg legs spread out into a cross. 

Attach your longest leg to a small glob of slime. Create an arc, or rainbow, of slime to connect the other three legs of the led together. 

conductive slime rainbow for St Patricks Day

3. Power your LED

Connect the battery hat to the 9Vbattery and strip the ends of the wires so you have more of it exposed (we exposed about a centimeter of bare wire). Then connect one wire of the battery to the small glob and the other wire to the arc of slime. If it lights up great! You’re ready to play! If it doesn’t light up switch the battery wires. This should make the LED light up. If not, double check you pulled the longest leg to the special spot.

4. Make a rainbow of colors

Once your LED is lit you are ready to color mix! See what happens when you move around the battery wire that is in the rainbow arc of slime (the slime that is connecting three of the four legs). 

As you move the battery wire you are changing the amount of voltage that reaches each leg of color. If you are closer to the green leg you will see more green, closer to blue you will see more blue. But there is a wealth of possible colors as you mix different amounts of red, green, and blue! What colors can you make? Are there any you can’t make?

Turn it into a slime based science fair project!

If you enjoyed this slime based science project you can easily keep the play going while also creating your science fair project! Here are some ideas on things you can take a closer look at:

How can I make more conductive slime? Ideas could include adding graphite powder, salt, extra baking soda, Gatorade instead of water, glitter, or…? Mix up various batches of the slime and monitor the brightness of the LED, or better yet, use a voltmeter to measure the resistance of the slime. Record and graph your findings

How can I make less conductive slime? Above we added items that are known to conduct electricity. What if we added items known to insulate? What if we added oil instead of water? Or made shaving cream based slime? Would it still light the LED?