Shrunken Heads Halloween Science Experiment

If you are looking for a cool Halloween science project that sounds gruesome but really isn't, then you should try making shrunken heads! We experimented with making shrunken heads out of apples and potatoes. You may have seen dried apple heads used in fall decoration before, but have you ever made one? We wanted to know if you could make them out of something other than apples, and how the process worked.

By designing, carving, preserving and drying out produce into these funny little Halloween decorations you can incorporate some art into a science investigation, adding some STEAM to your curriculum at home or school. This open-ended experiment is also a great way to allow your students or children to design their own investigation about food preservation, bacteria and enzymes!

This post contains affiliate links, meaning I will be compensated if you make a purchase after clicking a product link. Please see disclosures for more details.

 

How to Make Shrunken Apple and Potato Heads

First, we'll give you the directions we followed to make our shrunken heads. There are many ways you can complete this investigation, so read on to find out what worked and what didn't, further experiment extensions, and the science behind this project.

To make a shrunken apple or potato head you will need:

• Apples
• Potatoes
• Lemon juice (at least 1 cup)
• Salt (at least 2 Tablespoons)
• a paring knife or pumpkin carving tools
• Measuring cup
• Measuring spoons

 

How to Make a Shrunken Apple or Potato Head

First, we peeled the apples and potatoes. We found directions that said to core the apples from the bottom. We did this, but would like to try it next time without doing so. You'll see why below!

Next, we made a solution of 1 cup lemon juice, and 2 Tablespoons salt. After the apples and potatoes were peeled, we popped them in the solution quickly to keep any browning from happening before they were carved.

Then we carved faces into the apples and potatoes. Carving pumpkins is one of my favorite parts of Halloween, so designing these miniature versions was really fun!

Once the apples and potatoes were carved, we soaked them one at a time in the lemon and salt solution for one minute on each side. Then set them on a towel and pat the excess liquid off.

Next we needed to dry and shrink our apple and potato heads. The options are setting them in a warm dry place for a couple of weeks until they shrivel, or put them in the oven at low heat for a long time. We opted to dry them in the oven. Against our better judgement, we took some online advice and loosely wrapped the apples and potatoes in aluminum foil, and put them in the oven at 200 degrees for several hours, checking every hour or so.

The foil kept too much heat and moisture in, and one of our apples quickly turned into mush! It was a small apple, so this could also be another reason this happened. We kept the foil around the "heads" but opened it so that some of the moisture escaped.

Our potatoes were unscathed, but the larger apple had a sunken look as the bottom got pretty squishy. This is also why next time we might try to do this without taking the apple cores out. There wasn't much support for the apple in the oven. We'd also like to try air dry them as well.

We knew they were done once the apple was spongy and shriveled, and the potatoes had grown very hard.

You can then decorate the shrunken heads any way you want! We added just a few little marker highlights to our potato heads. They came out pretty cute! You could add hair, hats, or even make some fun food sculptures with them!

The Science of Shrunken Apple and Potato Heads

Drying fruit and vegetables is a method of food preservation that has been used for a long time. In this experiment, we helped to preserve the apples and potatoes with lemon juice and salt. There are many other food preservatives that you could try in an experiment like this. Can you design a different experiment using another preservative?

Food Preservation and Decomposition

You probably already knew that lemon juice keeps apples from turning brown once they are sliced, but how does this work? Enzymes are released from the apple when you slice into it and break the apple's cells. The enzymes react with the oxygen in the air, and the apple begins to brown. It doesn't take long for bacteria to settle on exposed fruit and begin the decomposition process.

If you're looking for another great apple preservation experiment, check out this one we published featuring the Zoey and Sassafras book, Monsters and Mold.

Speaking of decomposition, you'll definitely want to try this Pumpkin Jack experiment with your Jack-o-lantern this year! 

Lemon juice is acidic and by adding it to the apple, you lower the pH of the apple. The acidity prevents the enzymes from reacting, and helps prevent bacteria from settling in.

Salt helps preserve food because it lessens the water available in the food for microbes to grow in. The combination of the two ingredients used in the experiment help to prevent the apples and potatoes from rotting and from remaining too wet.

What other food preservatives, or types of fruit and vegetables could you carve to create shrunken heads?

Extensions for this Halloween Science Experiment

This project led to all sorts of new questions. Here are some things we are wondering:

• How would the experiment go differently if we hadn't cored the bottom of the apple?
• Would air drying the apples and potatoes resulted in a different effect?
• What other preservatives we try?
• What would happen if we left the apple and potato heads in a cup of salt for a few days? 
• Could we dry the heads by sticking them in a cup full of rice for a few days?
• What other fruits and vegetables could you "shrink"?

We'd also like to try decorating and making some cool Halloween art with our shrunken heads.

STEAM Saturday: Halloween STEAM Activities 

 

The first Saturday of every month we like to get together with some of our blogger friends to share some awesome STEAM (science, technology, engineering, art and math) activities with you. This month they are all Halloween themed!

Dry Ice Bubble Crystal Ball :: Science Kiddo

Frankenstein's Frozen Brain Halloween Science Activity :: Little Bins for Little Hands

Shrunken Heads Halloween Science Experiment :: Share It! Science

Tensile Strength Experiment | Find the Strongest Spider Web :: From Engineer to Stay at Home Mom

You also will want to try this apple-themed fall STEM activity. 

STEAM Kids Halloween Activities

Looking for more excellent Halloween STEAM activities? Click the image below to learn more about STEAM Kids Halloween.

Monsters and Mold: An Apple Experiment

Kids love gross science. Sometimes things are so gross they are cool! So of course, they will be on board when you try this science experiment. Challenge kids to see if they can keep an apple from rotting using preservatives. They will design and carry out their own science experiment. This is a great activity for school or home.

This post contains affiliate links, please see disclosures for more information. 

Before you dive into the science, I'd highly suggest reading the super fun book, Zoey and Sassafras: Monsters and Mold. In this second book of the Zoey and Sassafras series, science-minded Zoey must systematically experiment to find what will help a monster with an embarrassing mold problem.

 

This illustrated chapter book, is geared for readers in Kindergarten through 4th grade, and also makes for an excellent read-aloud to kids of all ages. The book series by Asia Citro features a curious girl named Zoey who loves science and animals. She is a strong, relatable character and will resonate with any kid who loves finding the answer to a question, even if it means getting a little dirty. The stories also include a bit of fantasy, adding to their appeal. 

The Apple Science Experiment

Just like when Zoey had to test different things to see what would keep the mold from growing on monster fur, kids will investigate what preservatives might keep an apple slice from rotting.

Although it is best to keep the project open-ended and really let the kids take the lead, you might want to have the following available for this experiment:

• Clean recycled glass jars, beakers or canning jars (kids might also use zipper style baggies, but I like using something that can be washed and reused easily! 
• Apples
• Vinegar
• Salt
• Sugar
• Honey
• Citric acid (used in preserving food)
• Fruit Fresh (an antioxidant used in canning food)
• Zoey and Sassafras science journal (free printable!)

Although there are a variety of ways students might want to design their experiment, here is one option:

1. Slice the apples into fairly even slices. (If you are really trying to go for accuracy in your experiment you can even weigh them on a food scale.)

2. Set up one slice in a jar as is. This will be the control for the experiment.

3. Determine how much "preservative" you will use on each slice of apple. In our experiment we decided to use 1 tsp each of salt, fruit fresh and honey. You could use just about anything, but this is a good opportunity to teach about being consistent with your measurements.

4. Set up as many apple slices in jars as "preservative" you want to test. For example, if you are testing salt, sugar, honey and vinegar you will need 5 jars; 4 for the apples with preservatives, one for the control.


5. Sprinkle or pour your preservative on the apple slices, trying to cover both sides.

6. To keep fruit flies under control, you'll probably want to cover your experiment, either by placing the lid back on the jar, or plastic wrap on top. Remember that sealing up the jar will also help preserve the apple slices, so take this into consideration when you are discussing with kids. 

Then, make some observations and wait! This is what I would have called a "patience experiment" when I was teaching elementary science.  Decide how often to observe- every day? Every 3 days? A week? and then stick to that plan.

We're not going to leave our results here, we want you to try this one yourself!

You can use this free printable Zoey and Sassafras science journal to keep track of the experiment.

After Your Apple Experiment

Further discussion points:

• What variables may have affected what happened? Were they things we could control for?
• Why is it important to set up a "control" in an experiment? 
• How is our experiment different from how decomposition occurs in nature? How is it the same?

Explore decomposition further with this Pumpkin Jack activity!

If you are looking for another great activity involving decomposition, you might want to build your own worm compost bin for home or school by following these easy directions.

You will also definitely want to check out this Insect Investigation using the first Zoey and Sassafras book, Dragons and Marshmallows. 

Buy a Book and Help a Good Cause

You may not be aware of this, but when you purchase a book published by The Innovation Press, like Zoey and Sassafras: Monsters and Mold, you are not only getting a great book for the children in your life, but also helping others. For every 10 books sold, The Innovation Press donates one book to First Book, getting books into the hands of kids and schools in need.

Disclaimer: I received a review copy of Zoey and Sassafras: Monsters and Mold in exchange for an honest review. Zoey and Sassafras character art is used with express written permission from Marion Lindsay and The Innovation Press.

Discovering Decomposition with Pumpkin Jack

Looking for an easy science investigation? Here is one with something you probably have around Halloween- all you need is your leftover jack-o-lantern. Download the pumpkin observation sheet below and kids can learn about life cycles and decomposition in a clear and simple way. We've also included a book suggestion so that you can also include some great children's literature while you're at it! Try this easy pumpkin science experiment at school with your students or with the kids at home.

Decomposition is such an important ecological cycle. One of the best ways to explore it with children without getting gruesome is by learning about composting. This October you can turn the inevitable process of your Halloween Jack-o-lanterns rotting out into a science investigation.

This post contains affiliate links, meaning I may receive a small commission (at no additional cost to you) if you make a purchase through a product link. Please see disclosures page for more details. 

Read the Picture Book Pumpkin Jack

First, inspire kids by reading the picture book, Pumpkin Jack. In this story, a boy named Tim carves a Jack-o-lantern and names it Jack. He enjoys watching Jack's glowing face in his room each night, until Jack begins to go bad and Tim's mom makes him get rid of him. Tim puts Jack out in the garden and watches him continue to decompose and change throughout the seasons.

Easy Pumpkin Decomposition Science Experiment

You can observe a pumpkin and how it changes as it decomposes too. Every few days make an observation of your pumpkin. You can take a picture like I did, or draw what you see. Make some notes. You can use this observation sheet to keep track. If you put the observation sheet on the refrigerator or a bulletin board where you will see it often you can observe your pumpkin throughout the fall and maybe even in the winter and spring.

Things to observe:

• What color does your pumpkin change?
• Does it get moldy? What does it look like?
• Did you get a frost? What happens to your pumpkin after a frost? 

What's happening to the pumpkin during this process? Decomposition is nature's way of recycling nutrients. Exposure to the elements begins to break down the pumpkin's cells and eventually decomposers like worms and other invertebrates, mold and bacteria go to work breaking the pumpkin down until eventually it turns into compost.

Brave scientists will want to investigate that mold and bacteria more closely. You might even want to see if you can grow some more to observe. To do so safely, get a bacteria science kit.

Learn More About Compost and Decomposition

Children can learn more about the fabulous creatures that work to turn living things back into soil at Growing with Science. For another great picture book about pumpkin decomposition to supplement this post, check out this link. Add to your science library with these children's books on compost and decomposition.

Want to try building a worm compost bin? You can use it all year long. Find out how here.

For more pumpkin STEM, check out my post, Discovering a Pumpkin: STEM Investigation

 

Not sure what to do with that surplus of Halloween candy? Try these science experiments with candy.

Cool Halloween STEAM Projects: 

More autumn inspired science at my Pinterest page: 

Glimpse of the Garden: Week 25, A Race Against Time

'Tis the season for harvesting fruit and veggies. Maybe you are overrun with tomatoes or squash. What is the best way to preserve your harvest before science takes over and those beautiful veggies start to spoil? Luckily, there are several options depending on the amount of time you have to do it, and your level of expertise.

Harvesting your garden is also a great kid's activity. Kids love digging potatoes, harvesting popcorn, and pulling carrots. There is also a ton of science involved in food preservation, including concepts like: pressure, vacuums, bacteria, decomposition, life cycles, etc. There are so many ways to make this type of work a fun, learning experience for you, your students or children.

This post contains affiliate links, see disclosures for more details.

Tomatoes on the window seat, tomatoes on the counter, tomatoes in the freezer and tomatoes on the vine. I would love to make some pasta sauce with those beautiful Romas and San Marzanos, dice up the Costolutos and put them in jars. I would even like to roast some cherry tomatoes and pop them in the freezer for a mid-winter treat. I know what you are thinking, "Well then, less talk, more action!". Alas, you need a critical amount of tomatoes of each type before you begin to can, blanch, freeze or dry and they don't all ripen at once.

©SBF 2015

Gardening is part patience, part intense action. Here we are at week 25 of my garden adventure for 2015 and I've waited patiently for this moment to come. Once your produce is ready there is only a small window of time before it becomes overripe, or an opportunistic woodchuck, chipmunk or rabbit comes along...instead of "hurry up and wait" we're playing a game of "wait and hurry up".

©SBF 2015

So what is the rush? How can you preserve your beautiful produce to save for later instead of eating salads for the next 3 weeks? Why do you need to process it, heat it to a certain temperature, freeze it solid or dry it out?

Microbes

Microorganisms, such as bacteria, are ready to do their part in the decomposition portion of your plant's life cycle. The plant grew your produce as a way of disseminating its own seeds, not as a kind gesture or repayment for watering it all summer. Once it has grown its fruit, eventually it will spoil. Bacteria are everywhere, and can be helpful or harmful to humans. Many of the bacteria you find in ripening and rotting veggies are not the helpful kind!

©SBF 2015

How Can You Preserve Your Harvest? 

Drying or Dehydrating

Drying foods to preserve them was most likely another happy accident. The sun and wind are pretty good dehydrators. Most microbes that cause disease enjoy a moist environment to multiply in. When food is dried out it becomes an inhospitable place for those types of bacteria. You can dry produce in your oven or in an electric food dehydrator. Check out the Colorado State University Extension page for more information on drying and dehydrating your own vegetables. Electric food dehydrators can also be purchased fairly inexpensively.

Blanching and Freezing

Freezing veggies is a quick and fairly easy option to preserve them for later use. Before you freeze vegetables you should blanch them. Blanching is a process in which you heat the vegetables for a short period of time in boiling water. They are then removed and placed in an ice bath to stop the cooking process.

Blanching breaks down the enzymes that are at work ripening your food. The boiling action also helps to kill any microorganisms on the food. The blanched vegetables can then be placed in freezer bags or containers and frozen for longer periods of time. Different vegetables have different blanch times. See this link for the appropriate times for different types of produce.

Canning

Although a little more labor intensive, canning is one of my favorite ways to preserve food. If you follow a recipe and work carefully then the result is safe, well preserved food that looks awfully pretty in a jar, too. I use a heat bath canner. Basically this means that after your jars are packed you boil them for a certain amount of time to destroy any harmful microorganisms and to vacuum seal your jar shut.



Recipes for canning fruits and veggies will help you to determine if you need to add anything acidic to the jars to help preserve the food. Lemon juice and citric acid are common natural additives to preserving food canned at home. Microorganisms cannot tolerate acidic environments. I will be chronicling the process of canning my tomato sauce for you in a future post- stay tuned. For some great tips and recipes for canning, you should visit the Pick Your Own site.

For tried and true canning recipes, I recommend  Ball Complete Book of Home Preserving

©SBF 2015

I'm excited this year to have produced enough tomatoes to make some sauce and can it for the winter. Slowly but surely, the tomatoes are ripening (I need 10 lbs of them). We're almost there, just some more patience. Then someday soon the tomatoes will be ripe and they will no longer wait. Time for that intense action I spoke of earlier. I will begin the job of blanching and peeling and cranking the food mill. I'll slowly simmer the sauce and then pack it into jars and put them in a hot water bath. It will be hours of work, but well worth the effort, the patience and time. 

More on the science behind food preservation:

• Education.com- Food Preservation Science Fair Project
• How Stuff Works- Food Preservation
• University of Minnesota Extension- The Science of Freezing Foods

Discovering a Pumpkin: STEM Investigation

Holidays can be a great time to do some theme based learning. The activity ideas here are perfect for your unit on pumpkins. It is easy to turn observing a pumpkin into an engaging STEM lesson for your students or children at home.

There are so many opportunities for math and science when you study pumpkins. Not to mention, they are easy to find in the fall. You can even make a pumpkin unit interdisciplinary by thinking of the history and impact on culture pumpkins have had. Read on to find out how you can use them for more than decoration this fall!

This post contains affiliate links, meaning that I may earn a small commission for purchases you make (at no additional cost to you). See disclosures for more details.

Studying Pumpkins

When I was a classroom science teacher I would study pumpkins with my 3rd grade class. During the fall we would investigate the pumpkins that they planted in the school's garden the previous spring when they were in 2nd grade. We would measure and draw, count seeds and end by making a recipe. You can find my lesson plan and student printables in their entirety here.

Pumpkins! (Jackie, Flickr.com)

Pumpkin STEM Investigations 

Here are some ideas for including some STEM in your pumpkin learning this fall.

Observe

What is the color of your pumpkin? The shape? What can the outside of the pumpkin tell you about how this pumpkin might have grown?

Count

How many creases do you count on the outside? Why do you think some pumpkins have more or less than others? How many seeds are inside?

     

Mass

How much does the pumpkin weigh? How much do the pumpkin seeds weigh? Do heavier pumpkins have more seeds?

Does it Float? 

Make a prediction of whether or not your pumpkin will float. (You'll have to try it and see for yourself!)

Want to do the complete Pumpkin STEM lesson in your classroom or homeschool? Grab the lesson plan and student printables here.

Using Pumpkins Across the Curriculum

Throughout the years I have found other resources and ideas for pumpkin science to tweak my lesson plan. I have put some of my favorites and those I think others would find most useful in the resource section below.

Pumpkins can be the springboard for teaching Ethnobotany, or the scientific study how how plants have been used historically and culturally. You can cook with your pumpkins. Roast their seeds, make pumpkin cookies or pie!

Save the seeds (raw) and plant them in the spring to learn about life cycles and pollination! You can even use a pumpkin for a lesson in decomposition, try this activity that accompanies the book Pumpkin Jack, or this one that accompanies the book Rotten Pumpkin.

The great thing about using a pumpkin as a teaching tool is that it does not have to be used exclusively for Halloween or in the fall, you can learn from it all year long!

Gardening pumpkins throughout the summer at home or at a summer camp can be an engaging activity. I am sure there are many, many other science and math investigations to be tried! 

Pumpkin Learning Resources: 

• Pumpkin Facts
• Pumpkin Discoveries- Science and Math Lesson 
• Sid The Science Kid: The Decayed Pumpkin 
• Discovering Decomposition with Pumpkin Jack 
• Exploring Decomposition with a Rotting Pumpkin 

                              

Pumpkin optical illusion:

 

 

More Hands-On Halloween Science! 

Halloween Peeps Candy Ghost Experiment - JDaniel4’s Mom

Fluffy Zombie Slime - Little Bins for Little Hands

Halloween Fun:  Spider Science Activities for Kids - Growing With Science

Halloween Ghost Balloons - Mama Smiles

Halloween Science: Static Electricity Ghosts - The Homeschool Scientist

Halloween Robot Spider Craft - Inspiration Laboratories

Halloween Rock Painting for Kids using Physics - From Engineer to Stay at Home Mom

Edible Candy Corn Slime (Play Dough) - Teach Beside Me