Share it! Science : October 2017

Saturday, October 21, 2017

Roller Coasters and Outer Space: Gravity Activities for Kids

Some science concepts can be seem pretty big and difficult to grasp. Gravity and other forces that we cannot see can be tricky, particularly for elementary aged children. I love teaching with picture books, so the Let's-Read-And-Find-Out Science® Series has always been one of my favorites. Gravity is a Mystery by Franklyn M. Branley is a great example of one of these kid-friendly science books.

In this post we'll explore Gravity is a Mystery and the concept of gravity with a hands-on science and engineering investigation: marble roller coasters. You'll also find a free printable "Weight in Outer Space" worksheet and a list of further resources for teaching and learning about gravity. This post is part of the Let's-Read-And-Find-Out Science® Series hosted by My Joy-Filled Life blog.

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

Let's-Read-And-Find-Out Science®: Gravity is a Mystery

If you haven't read a Let's-Read-And-Find-Out Science book before, you are missing out. Written by many authors well versed in the fields of science and science for kids, they are books that are written in kid-friendly language, have engaging illustrations, and often include activity ideas and background information.

Let's Read and Find Out Science Activity and Book Series

The books come in 2 stages, stage 1 stories are books about simple concepts appropriate for preschool and kindergarten, stage 2 books explore more difficult concepts for elementary aged kids.

Gravity is a Mystery is a stage 2 book. In it, a scientist and his dog explore the mysterious force of gravity. It answers interesting questions like: What would happen if you dug a hole through the center of the Earth and jumped in? How does gravity pull on you and other objects? How does gravity work? What does weight have to do with gravity? Why do we weigh different amounts on different planets?

Gravity is a Mystery is an excellent launching point for science activities about gravity. Read on to learn how to build a marble roller coaster and calculate your weight on other planets. If you are looking for even more activities about gravity and forces, check out these gravity lesson ideas.

Build a Marble Roller Coaster

Building and designing marble roller coasters is an engaging STEM activity for just about any age. I have done this activity in the classroom and during family science night programs and it is always a hit with kids and adults.

What do roller coasters have to do with gravity? Once a roller coaster is pulled up the "lift hill" by a motor and released, the rest of the ride is controlled by the force of gravity, and inertia, or the tendency of a moving object to maintain its forward velocity. Thanks to gravity and inertia, a roller coaster can stay on its tracks as it spins and flips.

Supplies for Marble Roller Coasters Gravity STEM Project

You will need: 

Build the Roller Coaster

First, you'll need to prepare the foam insulation. Although you can build roller coasters out of many different types of material, I like this way best. Use the utility knife to carefully slice down the solid side of the pipe insulation.

Marble Roller Coaster STEM project

The foam is flexible and can be used over and over again. It is already split down one side to fit around the pipe, so by simply slicing down the opposite side, you can make 2 troughs that a marble fits perfectly inside of.

Marble Roller Coaster STEM project

Although you can use any type of tape, I suggest using painter's tape because it allows you to attach the roller coasters to most surfaces without damaging them. This way you can work across the wall, floor, tables and chairs. It also peels nicely off of the foam insulation, so you can re-use the pieces.

Start out by encouraging kids to build a simple design while they get the hang of how the marble will behave in the roller coaster. Expect to use a lot of tape during the design process!

Marble Roller Coaster STEM project

Once they've experimented through trial and error, add some more complex elements to the coaster. Challenge them to include hills, a loop-the-loop, a spiral or some other spine-tingling roller coaster element.

Marble Roller Coaster STEM project

Roller Coaster Gravity STEM activity

Other Ways to Build a Marble Roller Coaster

If you want to continue exploring the idea of roller coasters, you can also build them with recycled materials like we did here for our Family STEAM Night event.

You also will want to check out this really neat set of marble tracks for home or the classroom. I love how it lends itself to open-ended exploration, it won a toy of the year award in 2016 and is reasonably priced. Learning through FUN is the best!

Marble Tracks STEM toy
It would be super fun to have this on the refrigerator, wouldn't it? STEM and a snack!

Gravity and Weight in Space

The weight of an object is equivalent to how much the force of gravity is pulling the object towards the Earth. The strength of this force changes with mass and distance. The larger an object is, the greater the force of gravity. This is why the force of gravity from the Sun, which is enormous compared to the planets, can hold all the planets in orbit. Gravity is also stronger when the distance between the objects is smaller. This is why the planets are not pulled away from our Sun, toward another, further away massive star.

Gravity Lesson Weight in Space Printable

This relationship is also what would make us weigh different amounts on different planets. You've probably had some experience with this concept at a science museum or planetarium. You can calculate the weight of an object, or yourself, on a different planet. The closer the planet is in size to Earth, the closer your weight will be to your weight on Earth.

Use this free "Weight in Outer Space" printable worksheet to explore this concept with kids. It requires multiplication, so is best for upper elementary and above. Please note that I have chosen to use the weight of a pet dog rather than the student in this sheet. You certainly can also have students substitute in their own weight. I found in a middle school classroom setting some students were sensitive about their own weight, so this easily alleviated the issue.

Further Resources for Studying Gravity

Check out these lesson plan ideas and other learning resources for further study of gravity:
I also recommend these children's books about gravity:

Let's-Read-And-Find-Out Science® Blog Series

You won't want to miss the rest of the posts in the Let's-Read-And-Find-Out Science® series. Each includes a book and activities that complement the science concept. You'll find the entire series here.

Over 80 Educational Toys for Preschoolers under $15 at Learning Resources! Shop now!

Saturday, October 7, 2017

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!
Halloween Science Experiment STEAM activity

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.

You will need:


How to Make a Shrunken Head

Shrunken Head Halloween Science Experiment STEAM Activity

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!

Shrunken Head Halloween Science Experiment STEAM Activity

Halloween Science Activities
Shrunken Head Halloween Science Experiment STEAM Activity

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.

Shrunken Heads Halloween Science Experiment STEAM Activity

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.

Shrunken Heads Halloween Science Experiment STEAM Activity

Shrunken Heads Halloween Science Experiment STEAM Activity

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!

Shrunken Heads Halloween Science Experiment STEAM Activity

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?

Shrunken Heads Halloween Science Experiment STEAM activity

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.

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.

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

Halloween Science Activities
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 


Halloween STEAM Activities for Kids

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
Halloween Pumpkin Slime :: Figment Creative Labs
5 Little Pumpkins STEAM Activity :: Preschool Powol Packets

STEAM Kids Halloween Activities

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

STEAM Kids Halloween activity book