Last week was Shark Week, and that got us thinking about our fishy friends living in the ocean. How do they survive in saltwater, while other fish can only survive in freshwater? The great folks at STEAMsational have created a really neat experiment to help your kids learn about how saltwater fish can live in the ocean.
Before doing this experiment, let’s learn how fish can survive in saltwater. The fish have the ability to remove the salt from the water as they move through it. Most fish remove the salt using their kidneys. Sharks process salt differently, in that they have a chemical called urea that helps prevent salt overload in their bodies and a special gland that removes salt through their digestive system.
The process of removing salt from water is called desalination. To illustrate this concept, you and your child can make your own simple distiller at home! A distiller helps water evaporate and collect in a new container, leaving salt particles (which are heavier) behind. Here’s what you’ll need to make your own fresh water:
- A large glass container with a wide mouth
- A small glass container that is shorter than the walls of the large container
- Kitchen plastic wrap
- A rock or other heavy object (this still needs to be light enough that it won’t break through the plastic wrap)
- Salt
First, make your saltwater. Add salt to two cups of water on the stove; heating the water helps the salt dissolve faster. Mix in the salt until it is completely dissolved in the water. Pour some of your saltwater into your large bowl and place your small bowl in the center of the large bowl, being careful not to splash salt water into the center bowl. Make sure the center bowl sits on the bottom of the large bowl and is not moving. You may need to remove some saltwater to make sure the center bowl is stable.
Next, cover the top of the large bowl with your plastic wrap. Place your rock on top of the plastic wrap in the center of the small bowl to encourage evaporated water to drip into that container. Place the bowl in direct sunlight for several hours. Once some water has collected in the center container, take a sip – it should be fresh, no salt detected!
Check out the full experiment and the science behind it at STEAMSational HERE!
As always, get as creative as you want, and above all, have lots of fun learning together!
We’ll see you right back here next Saturday for another STEAM Saturday activity! Scroll through the rest of our website to learn how Critchlow Adkins is Building Brighter Futures for the children and families we serve!
