Learn about the process of accretion by playing the role of the Sun. Or, be a dust particle that turns into a planet. Register to explore the whole course here: https://school.bighistoryproject.com/bhplive?WT.mc_id=Slideshare12202017

1. TEACHER MATERIALS
ACTIVE ACCRETION
Purpose
This activity simulates accretion. The process of accretion is responsible for the formation of planets, so it is critical that students understand how this process
works. Previous resources have introduced the idea, but this activity asks students to experience the process in a more hands-on way, through role play.
Process
BIG HISTORY PROJECT / LESSON 4.0 ACTIVITY
Go to a large open space such as a football field or park. Pass out one copy
of the dust particle sign to each student—they’ll each play the role of “dust
particle.” You, playing the role of the Sun, should stand in the center of the
area (your “Solar System”). Have each student (“dust particle”) take their dust
particle sign and choose a spot around the “Sun.”
When the Sun yells “Go!” all of the dust particles should start moving around it,
walking in the same direction at a brisk walking pace. As they move, they have
to follow a few rules:
1. They must move towards closer objects. (The word object refers to a
student or group of students.)
2. They must move towards larger objects.
3. They must always move around a center point (the Sun).
4. When they’re close enough to someone else that their hands can reach
each other, they must link hands (or arms) and then move as a unit,
following the same rules as before.
As the students link up with other students, their “object” size will grow.
Periodically, you (again, you’re the Sun!) should yell, “Stop!” Once they’ve
stopped, one student from each group should run to the Sun to swap out their
sign for one that reflects their group’s new role, which is, of course, determined
by their new group size:
Number of Students in Group Object
1 dust particle
2 chondrule
3–10 meteoroid
11–14 asteroid
15–17 planetesimal
18+ planet
Continue the process until there is at least one planet orbiting the Sun. You
might want to repeat the game more than once to see if there are differences in
the resulting Solar System each time.

2. STUDENT MATERIALS
ACTIVE ACCRETION
Purpose
This activity simulates accretion. The process of accretion is responsible for the formation of planets, so it’s really important that you understand how this process
works. You’ve already been introduced to the idea, but this activity illustrates the process in a hands-on way that gets you out of your chair.
Process
BIG HISTORY PROJECT / LESSON 4.0 ACTIVITY
Your teacher will take you to a large open space such as a football field or park
and give you a “dust particle” sign. Yes, that’s your role: dust particle. Your
teacher—or a lucky substitute—will be the Sun and will stand at the center of
the “Solar System.” Take your dust particle sign and move to a spot somewhere
around the “Sun.”
When the Sun yells “Go,” all of the “dust particles”—that’s you and your
classmates—are going to move around the Sun. You should all move in the
same direction at a brisk walking pace. As you move, you have to follow a few
rules:
1. You must move towards closer objects. (The word object refers to you or a
group of you.)
2. You must move towards larger objects.
3. You must always move around a center point (the Sun).
4. When you’re close enough to someone else that your hands can reach each
other, you must link hands (or arms) and then move as a unit, following the
same rules as before
As you link up with other students and groups of students, your “object” size
will grow. Periodically, the Sun will yell, “Stop!” Once you’ve stopped, one
student from each group must run to the Sun to swap out your object sign for
one that reflects your group’s new role, which is, of course, determined by your
new group size:
Number of Students in Group Object
1 dust particle
2 chondrule
3–10 meteoroid
11–14 asteroid
15–17 planetesimal
18+ planet
Continue the process until there is at least one planet orbiting the Sun. Your
teacher might have you repeat the simulation more than once to see if there are
differences in the resulting Solar System each time.

3. DUST PARTICLE
< 0.1 MICROMETERS
about the size of a virus

4. CHONDRULE
< 0.5 IN
smaller than a marble

5. METEOROID
< 1 METER
the size of a large beach ball

6. ASTEROID
10 - 1000 KILOMETERS
the size of Mount Everest - the size of California

7. PLANETESIMAL
> 1000 KILOMETERS
about the size of Earth’s moon

8. PLANET
> 4500 KILOMETERS
at least the size of Mercury