Something about the gorgeous deep red color of cranberries makes me really happy. Maybe it is because we most often enjoy them during special holiday meals. But they also make me happy for another reason. The availability of cranberries at the supermarket during the winter holidays makes it the perfect time for this fun and educational cranberry raft engineering design challenge!
Fascinating Facts About Cranberries
- Did you know that cranberries float? That is why bogs are flooded when it is cranberry harvest time. The air-filled berries float to the top and are easy to gather. So let’s see how they grow, why they flood the fields, and how they harvest them!
2. Cranberries bounce due to those four air chambers.
3. Cranberries do not grow in water. Watch the video above for more information about why we always see them floating in water. It is not just to harvest them.
4. Only 5% of cranberries are sold fresh.
5. Cranberries were originally called Ibimi. The Pequot Indians of Cape Cod called the berry ibimi, meaning bitter berry. If you have ever eaten one, you know they are tart and bitter.
6. Cranberries have medicinal properties. Per Ocean Spray, Native Americans would blend cranberries, fat and venison (ground deer meat) to make a survival cake called pemmican.
7. Cranberries are 90% water.
8. Cranberries can whiten your teeth. Really! According to USA Today, natural cranberries have flavonoids that help prevent the growth of plaque, bacteria and gum disease.
Cranberry Raft Engineering Challenge
Now that you know that cranberries float, you can challenge your kids to build a cranberry raft! In this open-ended engineering design challenge, they will build a raft using cranberries and test to see how much weight the raft can hold without sinking.
Materials to Make a Cranberry Raft:
- fresh cranberries
- round, pointed toothpicks like these (flat toothpicks are not strong enough)
- a basin or tub like this one (to put water in)
- uniform objects to test the raft (coins, metal washers, marbles, dice, etc.)
Set Your Parameters
This is an open-ended challenge, meaning you can set as many, or as few, parameters as you choose. You can allow the use of as many materials as desired. Or, you can put limits on the materials, for example: “Using 10 toothpicks and 15 cranberries, build a cranberry raft that holds at least 10 quarters without sinking.”
It is also fun to allow a free build first, and then begin adding challenges later. This gives kids a chance to explore and understand the materials and their limits before designing a raft to specifications.
A professional engineer would understand the materials before going into the design process or would test them through the design process, just like this.
Build, Design, and Test
The most fun comes from building and testing the cranberry rafts. What shape works the best? How will you keep your load from falling in the water? etc. We think it would be a fun activity to do at Thanksgiving with your extended family to show them just how fun and educational homeschooling can be!
Once the rafts are tested, allow for some time to tweak and improve designs and try again. Kids love working on problems like this! You might want to engage in some friendly competition with them, or you could allow siblings (or friends, or students who participate in your co-op, etc.) to have a fun contest.
Well, using the word “art” might be stretching it, but I do think this popcorn cranberry garland turned out beautiful…
This is the perfect activity to do right after completing your cranberry raft engineering challenge because you can reuse all of your cranberries for the garland!
Engineering with Food
What other foods can you design an engineering challenge around? The weather isn’t always pleasant for heading outside in the winter and there are all sorts of specialty food items available during the time from Halloween through New Year.
Here are some ideas:
- If you’re looking for more scientific fun with cranberries, visit this post for more cranberry science!
- Or use gumdrops and toothpicks so see how high a structure you make.
- How much weight can a chain of candy canes hold?
- Which holds more weight, ribbon candy on its side, or upright?
- Can you build a sturdy gingerbread house without using anything to hold it together (like frosting)?
The possibilities are almost endless!
If you’re looking for a great hands-on STEM investigation, you won’t want to miss this one about pop-up turkey timers and melting point. My upper-elementary and middle school students always enjoyed it in those days before winter vacation.
Other Thanksgiving STEM Experiments
And here is another great Thanksgiving Day experiment to do with your family from KiwiCo!
Steve Spangler from Spangler Science makes science fun! If you are interested in more Spangler Science materials, we encourage you to visit their website here.