Do you like light? How about water? Cheap things to make? Well I have a project that is kinda cool if you can do it right. And I did it, so you shouldn't have a problem.
Step 1: Materials
The materials for this is a bit long, but most of them are really easy to acquire.
-Hearing Aid Batteries***
-Water (Not pictured)
*** An easy way to get watch batteries and LEDs are to find really cheap, junky toys at places like Dollar Tree or any dollar store and breaking them open to acquire the goods inside. I bought 36 "flashlight" toys(picture below) for a total of about $24. It yielded 108 watch batteries and 36 LEDs. Buying them separately would be about $13 for a 16 pack of batteries and roughly $2 per LED from Radioshack.
Step 2: Beginning
I'm skipping all the parts about your wonderful shopping trip and how you found so many cheap toys and got all the supplies you needed, and I'm going to start with you at a desk with all the materials.
First you should check your lights by placing a couple of the batteries together and placing the correct node on the correct side to get a light of any color. Generally speaking, the longer lead, or wire jutting from the light-up section of the LED, goes with the positive (+) side of the battery, and the shorter lead goes with the negative (-) side.
Assuming your LED is working properly, you will then need to pull out a piece of tape about 1.5 inches long. About 3.8 cm. Then you will want to carefully place four of the batteries onto the tape, end to end. See the second picture.
After you have placed the batteries, you'll want to roll the tape around the batteries, securing them tightly. See third picture.
Step 3: The Hard Part
After you have made your four-battery stack, you need to position the LED onto the the stack. This is very tricky and may take a lot of time. The best solution I found was to get a bit of the Saran Wrap and tightly coiling the wrap around the leads.
Once you have the leads secured, the light will be on now until the batteries die. Hopefully. Next you'll want to take a bit more Saran Wrap and wrap the battery stack and the light emitting part of the LED a few times. This will make a nice water-proof seal.
Make at least one more of these clusters for a better show of light. I suggest three for the best result, but two is a minimum.
Step 4: The Cup
Alright, about halfway done. So next you need to take your SOLO cup and cut it down to the second or third line up from the bottom. This should leave you with something like the picture.
After you've cut the cup, place the LED clusters into the smaller section. Make sure to tape down or otherwise weight the clusters so that they stay on the bottom. Add water now if you want. With the other part of the cup, tape the cut you made earlier, but tighten the cup so that the smaller base fits inside it without falling through.
Step 5: Done
So now you;ve made your cup of light. It should now make a pool of light and look decent. Hopefully. If you have any questions, comments, concerns, corrections, suggestions, or otherwise, please don't hesistate to ask/tell. I don't do a whole lot, so I should respond within a day or two. Thanks. -Amy