Almost everyone flails their arms when they're trying to maintain their balance. Why do our brains react this way? In this series of balance games, students discover how their bodies compensate when their centres of gravity shift.

The centre of gravity is the average location of the force of gravity on an object.  The centre of gravity of an object could also be called its balance point. If you support the centre of gravity, the object will balance. If an object is not supported directly below its centre of gravity then the object will topple over. This explains why a wide stance helps you keep your balance. As you move your centre of gravity (near your belly button) to and fro, it stays above your support (your feet).

In physical games, people must readjust their bodies so that their centre of gravity is directly above their base. They do this by leaning or by moving their legs and arms. When you're unbalanced, your brain automatically tries to shift your body so that your centre of gravity is above your base.

In this series of activities, we look at how the participants' bodies adjust to keep their balance, and maintain their centre of gravity over their base.

Example: Three-legged race.

The centre of gravity of the pair of participants is somewhere in between the two of them. They adjust to support their combined shape.

### Objectives

• Identify ways in which balance affects our daily lives.

### Materials

• Per Class or Group:
stopwatch (optional)
long ropes or flagging tape to mark start and finish lines

• Per Pair of Students:
1m length soft ropes or bandanas or strips of cloth

### Key Questions

• Why do you tend to “lose your balance” when you’re playing these games?
• How does the way your body compensates differ for each activity?

### What To Do

Three-legged race

1. Lay down start and finish lines at opposite ends of the playing area.
2. Divide class into pairs and hand out a rope to each pair.
3. Get the students to stand side-by-side and tie together their legs that are touching. Students can have time to practice coordination of their 3 legs.
4. Get the pairs of students to line up and race. The first team to reach the finish line wins!

One-legged race

1. Mark start and finish lines on the playing area.
2. Students must hop on one leg to win the race.
3. Only one foot can touch the ground.

“Tightrope” racing

1. Stretch out long ropes or tape side by side along the playing area.
2. Time the students as they race to the other end of the rope as quickly as possible with their feet always touching the rope. Balance is key!

Relay version: Divide students into teams. When a teammate returns from running the rope, she tags the next student in line and sits down. The first team to have all their teammates complete the race wins.

Back-to-back balance

1. Mark start and finish lines on the playing area.
2. Students pair up and stand back to back with knees bent (as though sitting in a chair).
3. Give students a couple of minutes to figure out how to move sideways together.
4. Line them up and have them race to the finish line, remaining back to back the whole time.
5. The first pair to cross the finish line wins!

### Extensions

• Figure out the centre of gravity and base of support for the person or team in each game.
• Diagram these concepts (stick figures work well).

Survivors

Artist: Jeff Kulak

Jeff is a senior graphic designer at Science World. His illustration work has been published in the Walrus, The National Post, Reader’s Digest and Chickadee Magazine. He loves to make music, ride bikes, and spend time in the forest.

Egg BB

Artist: Jeff Kulak

Jeff is a senior graphic designer at Science World. His illustration work has been published in the Walrus, The National Post, Reader’s Digest and Chickadee Magazine. He loves to make music, ride bikes, and spend time in the forest.

Comet Crisp

Artist: Jeff Kulak

Jeff is a senior graphic designer at Science World. His illustration work has been published in the Walrus, The National Post, Reader’s Digest and Chickadee Magazine. He loves to make music, ride bikes, and spend time in the forest.

T-Rex and Baby

Artist: Michelle Yong

Michelle is a designer with a focus on creating joyful digital experiences! She enjoys exploring the potential forms that an idea can express itself in and helping then take shape.

Buddy the T-Rex

Artist: Michelle Yong

Michelle is a designer with a focus on creating joyful digital experiences! She enjoys exploring the potential forms that an idea can express itself in and helping then take shape.

Geodessy

Artist: Michelle Yong

Michelle is a designer with a focus on creating joyful digital experiences! She enjoys exploring the potential forms that an idea can express itself in and helping then take shape.

Science Buddies

Artist: Ty Dale

From Canada, Ty was born in Vancouver, British Columbia in 1993. From his chaotic workspace he draws in several different illustrative styles with thick outlines, bold colours and quirky-child like drawings. Ty distils the world around him into its basic geometry, prompting us to look at the mundane in a different way.

Western Dinosaur

Artist: Ty Dale

From Canada, Ty was born in Vancouver, British Columbia in 1993. From his chaotic workspace he draws in several different illustrative styles with thick outlines, bold colours and quirky-child like drawings. Ty distils the world around him into its basic geometry, prompting us to look at the mundane in a different way.