Teachers.Net Lesson Plans

#91. Kinetic Molecular Theory with Popcorn

Science, level: all
Posted by Cec Knight (cec_knight@pcbe.edu.on.ca).
Peterborough County Board of Education, Peterborough, Canada
Materials Required: Popcorn, Hard Margarine, Hot Plate, 2 Beakers, (Optional: Hot Air Corn Popper, Salt , Paper Napkins)
Activity Time: 15 minutes
Concepts Taught: Heat , States of Matter, Kinetic Molecular Theory

Overview:

The object of the game is to use popcorn kernels
as molecules and the margarine as the bonding forces
between them. Heating produces physical changes in the
popcorn-margarine mixture which are analogous to the
melting and boiling of matter.

Preparation:

- Melt 50 mL of margarine and add 100 mL of popcorn kernels
- Place the beaker in a refrigerator to harden
- Warm the beaker slightly in hot water to loosen the solid,
remove it from the beaker and keep it in the fridge

Presentation:

- Do whatever introduction you usually carry out to states of matter
- When you are finished, whip out the solid and explain that the
corn kernels are the molecules in a solid being held by the forces
which are represented by the margarine
- Review the properties of a solid using the chunk as an example
- Plunk the solid in a beaker on a hot plate and warm it until the
margarine melts
- Pour the "liquid" back and forth between the two beakers
- Talk about the properties of a liquid etc.
- Heat the "liquid" in a beaker over the hot plate until the
molecules begin to pop (watch splattering hot margarine but
don't cover the beaker)
- As the popcorn leaves the beaker, talk about the properties of
a gas
- The kids will want to eat the popcorn. As they write up what they
saw and explain it, make another batch in the hot air
popper and pass it around