Page 3 - CH - 2 - LN - 2.2

Step 3: Your rotating arm is ready!

Now, make several rotating arms with different angles between the straws. Once you've made them,
compare the angles by placing them on top of each other (superimposition) and arrange them from
smallest to largest.

Passing through a slit

Let's do a fun activity with your rotating arms. First, gather several rotating arms with different
angles, but don’t rotate them during the activity. Take a piece of cardboard and make a slit in the
shape of one of your rotating arms by tracing and cutting out that shape.

Now, shuffle and mix up all your rotating arms. Your task is to find out which of the rotating arms can
pass through the slit. To do this, place each rotating arm over the slit and see if it fits.

Only the rotating arm with an angle that matches the angle of the slit will pass through it.
Remember, whether the arm fits through the slit depends on the angle, not the length of the arms
(as long as they are shorter than the slit).

Special Types of Angles