Boo Bubbles: Dry Ice Bubbles

We did this amazing interactive, science presentation for the children in our community attending our county's Annual Halloween Bash.
Our little vampire is holding a bubble full of gas!

We viewed this amazing tutorial from Sick Science to get started:

Here is what our supplies looked like....

We bought 3 feet of tubing from our local hardware store for around $5. We used a small portion cup to attach to the end of the hose and a kitchen funnel to the other end. We also used an empty 2 L bottle, cutting of the top as instructed in the video and a stable dish of soap water. (Not pictured- you will need heavy gloves to handle the dry ice & winter gloves for the children to hold the bubbles)

Since we chose a fairly wide funnel we did have to buy a fairly thick piece of hose. This did work well, but the wider and longer the hose, the more gas is needed to fill it up to make the bubbles- keep this in mind.

We did at least a dozen demonstrations during the event and only went through about 4-5 pounds of dry ice ($2/pound at a local grocery store). If you are going to do this demonstration multiple times, be sure to have an easily accessible source of warm water. The gas dies off when the water gets too cold from the melting dry ice and when all of the dry ice chunks melt.

Have plenty of winter mittens available. Having a child wear one set really allowed them to handle a large, gas filled bubble without it popping right away.

Here are some of the conversations we had while enjoying this experiment:

"Wow this is the best experiment ever!" 

"Why do you have to put gloves on to touch the ice?"
"It is very cold. It is -60 degrees Fahrenheit. When something is that cold it can damage your skin if you touch it without gloves."

"Can you touch the bubbles without gloves?"
"Of course. They are regular bubbles with carbon dioxide gas inside, which is the same gas your breath out of your mouth. The gloves help protect the bubbles from the oils on your skin which will make the pop right when you touch them."

"Why does the ice bubble up and create fog?" 
"Dry ice never melts into a liquid like regular ice. It turns from a solid straight into a gas- which is called sublimation. When we put the dry ice in warm water it changes into a gas faster, rising out of the water, into our tube and forming a bubble filled with gas/carbon dioxide when the other end is dipped in soapy water."

In the end, after touching the green bottle and feeling how hold it was, some of the kids wanted to see what it felt like to dip their hands in the water. Since they had a great deal of soap on their gloves they created a soapy volcano- and interestingly enough popped quickly rather than gaining momentum.

Tip: the tall liter bottle with the elevated bottom hooked up to a moving hose did create some issues. We had at least 3 fairly large spills (just water- but it did get the table and floor wet). If we did this in the future we would create a Boo Bubble set up like the one in the video below with a closed jar:

You would really only need the closed container and the spigot instead of the funnel and you could still use the single portion cup on the end of the hose.

All in all a very fun experiment we are looking forward to repeating next year!