Who knew that putting snow in a bag could make for a fun science experiment and give such a snow reaction. This is a great winter-only kind of activity you definitely should try this winter.

Snow Reaction in A Bag Science Experiment

*This post may contain affiliate links, see my disclosure policy for more information.*

Looking for something to do on a really cold day? How about grabbing a Ziploc bag and some snow for a science experiment. It really simple. All you need is a Ziploc bag, some snow, and an Alka seltzer or two. If you bought some to make the lava lamps then you probably still have some on hand.

Click here to save this to Pinterest for later.

What You Need:

How to Create a Reaction in a Bag of Snow

Now if you are like me, you don’t want to go outside in the freezing -42C windchill, even if it is just to fill a bag with some snow. That’s why we have kids though right? To make them do it.

I drew a snowman face on our Ziploc bag, just to make it cuter. Fill it up with snow, but don’t pack it in tight, just fill it loosely. Before you seal the bag, add in a few Alka seltzer.

I laid a thick towel over my table, just in case it exploded on us. But this is optional.

We watched it inflate over a period of about an hour. It slowly expanded as the snow melted and caused a reaction with the Alka Seltzer.

Snow Reaction in a Bag

Yield: 1

Active Time: 5 minutes

Additional Time: 1 hour

Total Time: 1 hour 5 minutes

Difficulty: Easy

Estimated Cost: $1

Who knew that putting snow in a bag could make for a fun science experiment and give such a snow reaction.

Materials

snow
alka seltzer

Tools

large Ziploc bag
large towel - optional

Instructions

I drew a snowman face on our Ziploc bag, just to make it cuter. Fill it up with snow, but don't pack it in tight, just fill it loosely.
Before you seal the bag, add in a few alka seltzer.
I laid a thick towel over my table, just incase it exploded on us. But this is optional.
We watched it inflate over a period of about an hour. It slowly expanded as the snow melted and caused a reaction with the Alka Seltzer.

How It Works:

Alka-Seltzer is made of citric acid and sodium bicarbonate (baking soda), which is a base. When the tablets are dry, the acid and base powders don’t mix, but as soon as they are immersed in water they mix and react to form carbon dioxide gas.

The same type of reaction is made when you are baking and you mix baking soda and vinegar together.

You can see just how much it expanded here:

After an hour, my kids stopped caring so we stopped. There was still one out of four tablets that hadn’t had a reaction, so it would have continued as the snow melted.

They gave it a solid hour which is pretty good.

While we had this going we watched an episode of Magic S chool Bus – season 1 episode 13 – Kicks Up a Storm. You can also find great science kits that dig deep into the science of weather if your kids are interested.