By Kimberly Flessner
Objective: To see how water is purified when it evaporates during the water cycle.
Materials: For each group of 3, they will need;
- 1 gallon “zip-loc” bag
- 1 12oz clear plastic cup
- food coloring
- clear packing tape
- colored water
- colored salt water
- pond water
- soda pop
- a method to hang the bags window or light source
- Each group will take a 1 gallon “zip-loc” bag. Holding the bag by a top corner, secure the plastic cup so the mouth opens to the top corner straight up and down with the packing tape in the middle of the inside of the bag.
- Each of the groups will have a different liquid. A small amount of this liquid (~1/4 the cup) is placed into the cup in the bag, being careful not to spill into the bag.
- Blow air into the bag and seal it up.
- These miniature ‘water’ cycles then need to be hung in direct sunlight if possible.
- Each group then observes their ‘water’ cycle over the following weeks, to determine where the “impurities” in the water are left.
- The food coloring and salt/impurities should be left behind in the cup.
- I would start this activity ahead of time, so when you are discussing the water cycle, they have already started to cycle.
- This is a great long-term observation activity and sharing experience.