This document provides a worksheet for an activity to identify and classify different types of plastic objects based on their identification codes. Students are asked to make a list of plastic objects in class and classify them in a table according to their codes. They then conduct an experiment to test the density of different plastics by predicting and observing whether samples sink or float in water, and comparing this to known plastic densities. The goal is for students to learn to identify different types of plastics and understand properties like density.

1. WORKSHEET
KNOWING THE PLASTICS AROUND YOU
TECHNOLOGY 3º
1. IDENTIFYING PLASTICS
1.1 Make a list of the plastic objects we have in class. Look for the code (it
should be printed) and classify them according to the table industrial
plastics (you filled it in researching in the Internet).
(on your notebook, build your own table including as many rows as you need)
Nº
Object (name and/or
drawing)
Information found
(number and/or
name)
Summary (number and
abbreviation)
1
2
1.2 CONCLUSIONS. Build your own conclusions, for example:
 most of … are made up of type…
 the most common is…
Box for conclusions
MAKE A BIGGER TABLE IN
YOUR NOTEBOOK

2. 2. DENSITY TEST
The activity is based on the application of the Archimedes principle. The
result of the principle of Archimedes is that if we immerse a body in a fluid, the
body sinks if its density is higher than that of the fluid, it floats
if its density is lower.
2.1. THEORETICAL PART: imagine a container with water in which we introduced
different types of plastics. If the density of water is 1000 kg/m3 and the
density of plastics are in the table above, choose 5 objects and fill in the second
column.
Objet (name and type)
Expected result (sinks or
floats?)
Experimental result
(sinks or floats?)
2.2 EXPERIMENT: introduce those objects, one by one, in the container with
water, and fill in the last column of the table above.
2.3. CONCLUSIONS: write the conclusions of the experiment
Box for conclusions