Have a STEM Inspired Sand Castle Day! - cohesion activity
Every year on August 19th, sandcastle enthusiasts celebrate International Sand Castle Day. This whimsical holiday is all about embracing creativity, enjoying the beach, and building intricate sand castles and sculptures! Believe it or not, this can also be a fun opportunity to express art while also teaching about physics! How? Well, as kids build a sand castle, you can talk to them about “cohesion” which is when two similar molecules stick together… read on to see how!
How Does Sand Stick Together?
You will notice that dry sand doesn’t stick together, but wet sand does! This is because when sand becomes damp from the water, the water fills the spaces between the sand particles, creating a type of "glue" that binds the sand together. This is because water is “cohesive” - which means water molecules naturally want to stick to other water molecules. So, the water fills the space between the sand particles and causes them to stick as the water clings to other water. It is kind of like the water is holding hands around the pieces of sand and keeping it from falling apart! This is what helps us to make a sandcastle! But once all the water is gone, the sand castle will crumble.
Using Sand Castles to Understand Cohesion
If you are able to get to the beach, or get your hands on some sand and water in a space where you can get dirty, then you can use sandcastle building to understand cohesion. All you need is sand, water, and tools to build a sand castle. Then just follow these simple steps!
Start with DRY sand and ask the learners to try to build a sand castle. Quickly they will see that this does not work!
Now, wet the sand and ask them to try again.
Soon, the learners will be able to create all kinds of fun sand castles and sculptures!
At this point you can explain to them that the water is like a “glue” because water likes to stick together. This is called cohesion, when two molecules that are the same stick together!
You can let the sandcastle dry out and come back the next day to show that they will once again break apart without the water!
This is a fun and artistic way to teach about an important physics concept! And it is a great excuse to enjoy some time outside learning hands-on!
Conclusion
International Sand Castle Day is an excellent opportunity to appreciate the wonders of sculpting sandy masterpieces, and understanding physics! By engaging in the joy of creating sandcastles, kids can explore their imagination, develop their fine motor skills, and learn hands-on! So, on August 19th, let's gather our buckets, shovels, and celebrate this wonderful day together, one sandcastle at a time!
