Be a superhero and rescue the LEGO ice minifigures from drowning in freezing water using science! Learn why salt melts ice and engage in imaginative play.
*This post contains affiliate links. Please see our disclosure policy.
HELP! The LEGO minifigures are drowning in icy water! Can you save them using science?
We did a fresh twist on this classic science experiment for kids by fishing for LEGO ice minifigures. That’s right. We rescued the LEGO guys. My kids felt like superheroes.
Fishing for LEGO Ice
Glass Full of Cold Water
Piece of String or Yarn
- A few hours or days before you want to do this experiment make some ice using the silicone LEGO molds. You can either make regular clear ice or add some food coloring to the water before freezing to make colorful LEGO ice minifigures like we did!
- When fully frozen, drop the ice into a cup of cold water. (The colder the water the longer your LEGO guys will last before melting!) Notice how the ice floats on top.
- Place the piece of string or yarn across the top of the LEGO ice.
- Sprinkle some salt on top of the string and ice. Be generous with the salt. Wait for one minute.
- Pull the string out and see if your LEGO ice minifigure comes with it!
Were you successful rescuing your LEGO ice guys? If not, what else can you try?
We did this experiment several times using different kinds of thread, string, and yarn to see what worked best. We varied the amount of salt we sprinkled and varied the temperature of the water. Keep track of your observations!
Fishing for LEGO ice minifigures opens up a whole dimension of imaginative play in addition to being an educational science activity. The kids created all kinds of scenarios where their LEGO guys fell into the water and they had to be rescued. This is one of our all-time favorite science experiments!
The Science Behind Fishing for Ice
When salt is mixed with ice it lowers the freezing point. Usually water freezes at 32° F (0° C), but when it is mixed with salt it lowers the freezing point significantly. This simply means the ice melts. You may have noticed that in the winter people sprinkle salt on their icy stairs and walkways to make the ice melt. We have used this same trick to make yummy treats like fruity ice slush and easy homemade ice cream!
When salt is sprinkled over ice it melts. However, when it is used in such a small amount, like in our experiment, the water around the ice freezes again quickly. This means that the string gets trapped as the water around it refreezes, thus making it stick to the ice. Isn’t that cool?!