Introduction: Saltwater Battery + Lesson Plan
Electricity can be very complex, but it doesn't have to be! In fact, it's so simple we can generate electricity with a small cup of saltwater. This project is a great introductory project to electricity and is ideal for middle schoolers all the way to high school seniors. If you're using this in a classroom setting, please view the attached documents for a lesson plan, lab guide, and post lab assignment. The lesson plan is meant for students aged 14-18.
For each group, you'll need:
An Eight oz. Plastic Cup
180 mL of Water
30 grams of salt
2 pieces of ten cm. Conductive Wire (Copper works best)
A stirring rod or spoon
2 Alligator Clips
Optional: Scotch Tape
Step 1: Add Saltwater to the Cup
Begin by making sure your plastic cup is empty and clean. Pour in the water, and add the salt. Using a stirring rod or spoon, gently mix the solution until the salt is fully dissolved.
Step 2: Thread the Wires Through the Alligator Clips
Thread the wire through the holes in the end of the alligator clip. Wrap the wire around the base to ensure that the wire stays in contact with the clip. Do this with both clips.
Step 3: Insert Your Wires
Once the salt has dissolved, insert the wire into your cup of saltwater. The wires shouldn't touch each other and should only come in contact with the water and the cup. If you're struggling making the wires stay apart from one another, tape the wires to the inside of the cup.
Step 4: Attach the Multimeter
Make sure the multimeter is turned on. The multimeter should be set to DCV 20. Attach the red cable to one clip, and the black cable to the other clip.
Step 5: Watch Your Current
Tada! You successfully created a battery and an electrical current! The multimeter should show that there's an electric current flowing through it. Although there isn't much to watch, you will see the display on the multimeter change. If enough of the batteries are joined together they could potentially power a small light.
You can take the experiment further by changing the salt to water ratios and recording which one produces the most voltage, experimenting with different wire materials, or using a fluid other than water.
Please take the time to view the attached documents if you wish to integrate this into a lesson plan.
Participated in the
Classroom Science Contest
3 years ago on Introduction
I do want to be positive but the demonstration fails on the essence of an electrochemical cell or any battery. That is that the tow electrodes must be different, that why they have separate names. In case of metal electrodes the cell voltage depends on the difference in nobility of the two electrode metals. Siver, copper,tin (noble, will become positive)) versus iron, aluminum, zinc magnesium (less noble, will become negative). So instead of two copper wires one should use (fresh sanded) pieces of two different metals. For instance: keep one copper wire en connect the other clip to the the metal (propably nickel coated) spoon (of course submersed in the beaker) . Voltages of more than 1 Volt wil be measured.