Challenge - Sink a Marshmallow

  Getting stir-crazy one snowy, house-bound day, I said to Kay, "I have a challenge for you." Of course she was intrigued and followed me to find out what it was. She watched as I got out a glass cup (a measuring cup was the only clear one I could find), filled it with water and grabbed a bag of marshmallows, setting everything on the table. "I bet you can't get this marshmallow" (and I took one from the bag with dramatic flair) "to sink." 
    "I can," she declared, before the words were even out of my mouth. (I love this kid's confidence!) 

  So she dropped it into the water and - it floated. She took it out and threw it in the water...still floated. She did this several times and then tried squeezing it. I explained that it was floating because there was a lot of air bubbles inside the marshmallow.

She continued to smoosh it between her fingers, maybe just because she liked the feel of it more than having any idea of helping to sink it. 
  I loved listening to her think it out though. She tried throwing it into the water, thinking the extra force would get it to sink. She tried squeezing it, making it smaller, making it flatter. Most importantly, she kept trying at it. 

  Eventually I tried to help (and that's where the pictures stop...marshmallows are sticky!) and we ripped off smaller pieces of marshmallow and tried to flatten it, getting out all the air bubbles. In the end, we managed to get the piece of marshmallow to drift toward the bottom but it slowly rose to the top anyway. Kay was satisfied with that. And I was satisfied that I had let her try it out for herself, instead of jumping in to help (as I have a tendency to do too early!). 
  This marshmallow sinking idea came from Steve Spangler. You can check it out for tips on how to make this work. (I'd love to hear if you try it - especially if you get it to sink!)

Ready for more science ideas? Let's get to them...

Melting Ice Cubes  
{Stir the Wonder}
Why Are Polar Bears White? A Preschool Investigation  
{Still Playing School}
Icy Hearts Science Experiments  
{Little Bins for Little Hands}