Simple tutorial on how to make LED in a frozen water balloon.
Before we start, I do not take responsibility for water in your fridge (if the balloon pops), frozen batteries(you shouldn’t put them in fridge) and other potentially dangerous things in this project.
Sorry for bad video quality. It looks much better in real life.
You will need:
- Water balloon – could be small or big, depends on the size of ice ball you want to get. Note that, the bigger the balloon, the more time it takes to freeze it.
- 9V battery*
- 9V battery clip*
- 330 Ohm resistor*
- LED – whatever color you want, I used LED that slowly changes it’s color over time.
- Hot Glue gun with glue.
* you can use different batteries with different voltages (and different resistors to match it).
First of all create circuit similar to this one:


After that secure it’s connections with glue gun, to make it waterproof. Be sure to put as much glue as needed, otherwise water may damage the circuit:

(Optional)Test the circuit by putting the LED circuit in the watter, with battery connected – battery and clip must be outside the water!
Put finished circuit into a water balloon, 9V battery clip should be outside of it. After that carefully fill it with water and put it into the freezer (or fill it with air and don’t freeze it, then it will be a glowing balloon). Make sure, that LED is in the middle of balloon, otherwise the effect may be not as good as it can be. Wait until the water inside the balloon freezez. Take out the balloon, peel off it’s rubber, place ice ball on a plate/dish/… (to collect melting water), attach battery to a clip and enjoy the effect (and make sure, that water is not touching it).


Ideas:
- connect more than one diode (in parallel with resistors) – it will make balloon glow more,
- experiment with colors – use different LEDs,
- add glitter to water – it may make shiny reflections,
- use different balloon sizes.