Here's what you need:
- A large Ziploc bag
- Food dye
- A permanent marker
Here's what you do:
1. Begin by reviewing the water cycle diagram below. Remember that Frannie is making a simplified version of the water cycle. In reality, water can take many different paths and it can stay in one form for a very long time (did you know water can be stored in glaciers for thousands of years?)
|Image courtesy of the United States Geological Survey|
3. Mix the food dye and water together in the cup. This will make it easier to see the water as it moves!
4. Add gravel to your bag, then slowly pour the dyed water over the gravel. You can think of this as rainwater that falls on the ground (the gravel) and seeps into the spaces between the rocks and becomes groundwater. You have created an aquifer in your bag! An aquifer is an underground geological formation of sand, soil, gravel and rock able to store and yield water.
5. Seal your Ziploc bag and tape it to a window that gets a lot of sun. Over the next few days, watch as the water in your bag moves!
The sun will shine, warming the water until it turns into a vapor in the air (evaporation). When the water gathers and cools it will turn from a vapor make into a liquid (condensation). When there is enough condensation, the water will fall back onto the gravel (precipitation). This water will soak back into the aquifer (recharge) and become groundwater.