Chemistry Physics
features of matter States of matter
Age Group
12 13 14
Expected time
2 periods
Solid or liquid.PDF
beaker symbol

Solid or liquid?

What’s the mystery? Some materials do not act ‘normally’ when you exert a force on them. They become either more liquid or more solid. Bouncing putty is special type of clay with which it is fun to play. It bounces when you let it fall and it can be torn, stretched, and mashed back together.
Domain(s) Chemistry, physics.
Subdomain keywords States of matter, features of matter.
Age group 12 to 14 years old.
Expected time for the mystery Approximate time for teacher preparation: about 30 min.Approximate time in classroom: two individual 50-min lessons.
Safety/supervision There are no specific safety restrictions/regulations for these experiments other than the standard restrictions for every chemistry/physics lesson that involves experimentation.Attention: students may not be allowed to use boric acid in every country!Disclaimer: the authors of this teaching material will not be held responsible for any injury or damage to persons or properties that might occur in its use.
Preparation and list of materials Bouncing putty, modelling clay, chopping board (plastic), hammer, food colouring, liquid glue, liquid starch, potato starch, 3ml Pasteur pipette, heating coil with agitator, scale, magnifier, applicator, glass bar, measuring cylinder, wash bottle with distilled water, boric acid, polyvinyl alcohol, plastic wrap.
  • Students will learn about gravity, force, and the difference between liquid and solid states of matter.
  • The students will be able to explain ideas about viscosity, dilatancy, thixotropy, and rheopexy; however, teachers have to consider the complexity of the wording and whether or not students can manage the technical terms.
Resources In the following links, you can find explanations of the terminology used in this mystery in German:

Here, you see some more ideas about how to engage the students:

More experiments with WACKER-SILICONES. A CD and print version are available here: