# Labs from YSI 94 :

Simple Measurements.

*April Whitt*

CARA Yerkes Summer Institute, August 1994*
This is a Teacher's Guide.*

## Objectives

Students will determine the height of objects using shadows
## Materials Needed

meter sticks, protractors, Metric & English plastic rulers
## Procedures

**Problem:**

Students will determine a method for calculating the height of
a nearby tree or the observatory. They may not measure it directly.
Teams of students are taken outside and shown the objects to
be measured. Teams may brainstorm their own solutions. The only
equipment available to them is meter sticks and protractors.
**Possible Solution:**

Height of the building. Stand a meter stick or yard stick in a
vertical position and mark the end of its shadow. At the same time
mark the end of the shadow of the building. Measure the length of
each of the shadows. (Each student will mark and each student will
make measurements. If there are three students in a team, then the
team may have three different measurements.)
The height of the building can then be found by using a proportion
equation:

height of meter stick length of shadow of meter stick
--------------------- = --------------------------------
height of building length of shadow of building

**Example:**

Length of shdow of meter stick = 2 meters.

Length of shadow of building = 20 meters.

1 m 2 m
----- = ----- --> H = 10 meters.
H 20 m

**Important Disclaimers and
Caveats:**