Cranberry Science

It’s almost Thanksgiving and it’s time to make the cranberry sauce and why not throw in a quick bit of science while the kids help you make the sauce?  Cranberry sauce is quick and easy to make at home and we took some time to explore some fun with cranberries.  (When I mentioned this to my mother, she groaned and said, “Why do you have to find science in everything?”  To which I replied, “Because science is in everything we do!”)

Here’s what you need to get started:

• fresh cranberries
• dried cranberries
• glasses (I used some old jam jars)
• ginger ale (or any carbonated clear drink)
• knife (for adult use only)

Fresh vs. Dried Cranberries:

I had the boys compare the dried and fresh cranberries.  They held it in their hands and noticed that the fresh ones were round, smooth, shiny and hard.  The dried ones were “bendy”, wrinkled, bumpy and darker in color.  Then they tasted them.  You should have seen my son’s face when he tasted the fresh cranberries! (He spit it out so quickly that I couldn’t get a picture!)

Then I asked them what they thought would happen if we put both kinds of cranberries in water.  My middle son guessed that they would both sink.

 So, why do the fresh cranberries float and the dried cranberries sink?  We decided to cut a fresh cranberry open to see if that might give us any clues.

Aha! If you look closely, you can see that cranberries are filled with air pockets.  This allows them to float in water.  The dried cranberries don’t have any air in them and so they sink.

My eldest son decided to keep a record of our experimentation and our results.

After observing the cranberries in the water, my middle son wondered if the cranberries would “dance” in soda like raisins do.  (Check out my “Dancing Raisins” and “Hopping Corn and Cranberries”  5-minute activities to see what he’s referring to.  Super easy and perfect for the holidays when there’s plenty of soda around!)

So, of course, I grabbed a can of ginger ale and we added fresh cranberries and dried cranberries and observed what happened.

The cranberries DID dance, but not the same way as the raisins did.  I LOVE that my son was able to make the connection to an experiment we did awhile ago.  I guess they DO pay attention to their mom… sometimes.

Making Cranberry Sauce:

Tomorrow is Thanksgiving and I asked my sister-in-law if I could make the cranberry sauce, specifically so I could justify buying a bag of fresh cranberries to use to investigate.  So, I had my middle son help me make the sauce.  Measuring  is a great math skill and pouring and mixing carefully are great to develop fine motor skills.  I try to include my kids in cooking/baking whenever I can, even if it takes me 3 times as long to complete my task.

The fun part came when we added the cranberries to the sugar/water mixture.

As my son mixed, he heard some “popping” sounds.  As we looked carefully at the pot, he noticed the cranberries were “exploding”.

So I asked him why that might be happening.  This was a great way to bring back the concept that cranberries are filled with air pockets and when the air heats up, they have to get out of the cranberries so they “explode”.

He also noticed the sauce getting thicker and not so watery.  We talked about how the water was evaporating into steam and the cranberries were also helping to thicken up the sauce.

And now we’re ready for some turkey to go with our sauce!  Happy Thanksgiving!

The Science behind the Activity:

Who would have thought there was so much learning to be had from cranberries? Cooking/baking are great ways to expose children to how things can change when heated up, mixed, etc…  It’s a great time to bring in math concepts such as measuring and for the little ones, fine motor skills such as pouring and mixing.

Comparing the dried and fresh cranberries brings in the concept of observing changes and comparing/contrasting different items.  By cutting open the cranberry, we were able to explain why fresh cranberries float in water.