Exploding Lunch Bag

For those of you who know my kids well, they frequently (always) get into the kitchen, take out different equipment or ingredients and ask (demand) if they can make something.  Last week it was a banana and honey smoothie in the blender - end result was this smoothie for 2... or perhaps for 15!

This week it was the bicarb of soda.  They wanted to make a volcano again... You can imagine my delight when - just five minutes before lunch is ready, I'm finishing the cooking and setting the plates - I hear (on repeat) "I want to make a volcano.. I want to make a volcano.. Muuuumm, I want to make a volcano!" Perfect timing, kids! Thanks!

 It's been a while since we've worked with bicarb so I thought why not?

 

All you need for this one is:
One small zip lock bag
Bicarb of soda
Warm water
Vinegar
Measuring cup
Vinegar

You will need to do this outside - it gets a little messy... and if it's not a good day outside then do it in the kitchen sink or the bath!

Pour 1/4 Cup of warm water into a bag.

Add 1/2 a cup of vinegar into the bag.

Lay the tissue out flat.  Put in 3 teaspoons of bicarb of soda into the middle of the tissue.

Wrap the tissue around the bicarb of soda - only do this lightly - it will help buy you time when you combine the bicarb to the water/vinegar mixture.

Now really quickly zip up the bag and watch what happens!  These pictures were taken the first time we tried the experiment - it didn't work as well as we had hoped but it sure was fun!

 

 

The mixture started fizzing up ...

 

 

The bag started expanding...

 

And expanding - until it got really firm to touch...

 

The kids were so excited but really scared so they kept on running away, waiting for it to explode...

 

Then they ran back to it to see if it did explode...

Until finally we realized the bag had popped - just not how we thought it would! A small hole in the bag- created either by a blade of grass or the fact that the bag had expanded so much that it had ripped the bag.

We did try this experiment again - this time I shook the bag quickly after adding the tissue and bicarb  to the water/vinegar mixture and threw it on the ground (not the grass).  It exploded much more quickly and the boys were absolutely going crazy at what happened - they loved it! If I had more camera battery I could have shown you their faces - they loved it!

Nothing like a little Chemistry to please the senses! What happens inside the bag?  The baking soda and the vinegar eventually mix and when they do mix, you create an acid base reaction and the two chemicals work together to create a gas, (carbon dioxide - the stuff we breathe out). It turns out gasses need a lot of room and the carbon dioxide starts to fill the bag, and keeps filling the bag until the bag can no longer hold it any more and, POP!

Thanks, Science Bob for this cool experiment!