# Balance Ninja Center of Mass Challenge

This balance ninja activity is designed to help kids understand what the center of mass is and encourage critical thinking to solve the ninja’s balancing problem.

If your kids are anything like mine, they love to see what they can balance everywhere. My 7yr old is a little gymnast and the balancing she does is usually on her hands while she flips around.

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This balance ninja center of mass challenge activity is part of our Magic Tree House book activity series based on the Magic Tree House books by Mary Pope Osborne. This activity is a great way to pair a STEAM concept with book number five, Night of the Ninjas.

## MORE MAGIC TREE HOUSE ACTIVITIES

MAKE SURE TO GRAB THE MAGIC TREE HOUSE BOOKS 5-8 TO FOLLOW ALONG WITH MORE MAGIC TREE HOUSE ACTIVITIES!

## KEY ACTIVITY TERMS

• Center of Mass – the point where the mass of an object is concentrated
• Gravity – the force that pulls all objects downward on Earth

## Balance Ninja Center of Mass Challenge

To start this project, print the Ninja Template by clicking on the link above. Cut out your ninja. Tape one regular size craft stick on the back of one of the ninja sides.

Begin your challenge by attaching one penny to each foot of one of your ninja pieces.

Attach your pieces together. The pieces should align. Trim any excess paper if needed. Try to balance your balance ninja on your finger. Does it work? We found that only using one penny per foot didn’t shift the center of mass enough to balance our ninja.

This is where the challenge begins! We know that it is possible to shift the center of mass from the top of the ninja toward the bottom by adding weight. Ask your children to think critically about how they can add more weight to the bottom of the ninja.

### THE CHALLENGE: What can you do to shift the center of mass on your balance ninja?

Things my children thought of:

• Reducing the size of the craft stick (we cut it in half)
• Moving the craft stick toward the top of the ninja and balancing him upside down
• Adding more pennies to each foot

Ultimately, we created a kind of pocket on each foot using the two sides of the balance ninja paper. This allowed us to add more pennies without adding additional tape each time.

We added one penny and observed what happened to our balance ninja. This will shift the center of gravity in the direction of the added weight

We added another penny to keep our center of mass in the vertical center and tried our balance ninja again. It worked!

All of my kiddos got involved in the balance ninja fun even my 3yr old enjoyed feeling how the ninja balanced differently depending on what we were trying!

We decided to put our engineering skills to the test and built a stand so we could observe the changes visually as well.

We used 4 clothespins to build our stand (three new ones and an older peg pin!) This stand is also a lesson in learning about balance too!

## THE SCIENCE BEHIND YOUR BALANCE NINJA

The center of gravity or the center of mass is the point where the mass of an object is concentrated. If you support an object at its center of mass, it will balance or be in a state of equilibrium.

A great way to learn about the human body’s center of gravity is to put an object on the floor about 30cm from a wall. Stand with your back and heels against the wall and try to pick up the object on the floor. Can you do it?

Most people’s bottom keeps their center of mass over their feet (no one in my house can do this with our athletic leg builds!) and when you bend over, your bottom can’t counterbalance you.

## WANT TO CONNECT THIS GRAVITY ACTIVITY WITH OTHER STEAM BUCKETS? CHECK OUT THESE EXTENSIONS!

Technology – Use a robot like Gyrobot that relies on its center of gravity on two linear wheels that can move along a tightrope to help make this physical law more tangible!

Engineering – Build your own post like we did! We used two different types of clothespins to create a stable post for our balance ninja to perch on!

Art – Grab some pipe cleaners and make a balance mobile by hanging multiple objects from your hanger or pipe cleaners. Can you make each row balance?

Math – Try adding more pennies and compare the difference. Is it harder to balance? Easier?

We love incorporating books into our activities. Here are some great books about engineering to read with your activity!

## SIMILAR STEAM ACTIVITIES

PIN THIS IMAGE TO SAVE THIS MAGIC TREE HOUSE STEAM ACTIVITY

## More Magic Tree House Activities

Find more Magic Tree House book activities!

## Meet Toni, the Maker Mom behind Our Family Code

Hey there, I’m Toni! I’m a software engineer and Maker Mom that finds my joy in unleashing my children’s curiosity by exploring STEAM concepts with my fantastic five!

When I’m not chasing toddlers or raising tweens, you can find me tearing things up and putting them back together over here at Our Family Code.

I am the owner and content creator of multiple educational websites designed to increase access to STEAM & STEM education with a focus on teaching computer science and coding to kids of all ages!

You can also find out more about me by visiting ToniGardner.com!

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