Density and Buoyancy Activities for Middle School

Instructor: Julie Zundel

Julie has taught high school Zoology, Biology, Physical Science and Chem Tech. She has a Bachelor of Science in Biology and a Master of Education.

The topics of density and buoyancy lend themselves to some fun learning activities. This series of activities will enhance student knowledge, while allowing for student collaboration, experimentation and exploration.

Density and Buoyancy

Do you need to make the topics of density and buoyancy more exciting? This series of activities will help students understand density and buoyancy in a fun, interactive way. While these activities are geared toward middle school students, they can be modified to fit most grade levels and can be used along with textbook lessons or as standalone lessons.

Layered Liquids

This colorful activity allows students to layer a bunch of liquids to explore their different densities.


  • Graduated cylinders
  • Syrup
  • Cooking oil
  • Water colored with food coloring (to help distinguish the water from the ethanol)
  • Ethanol
  • Science journal
  • Pencils/markers


  • Divide students into groups.
  • Define density on the board.
  • Ask each group to order the liquids from those they guess are the densest to the least dense.
  • Tell students to place five milliliters of each liquid into a graduated cylinder in the order they wrote earlier (most to least dense).
  • Once the liquids have settled, have students draw how the liquids layered in their science journal.
  • Have students compare their original guess to how the liquids layered in reality.
  • Optional: have students calculate the density of each liquid.

Candy Bar Density

This activity helps students understand that the size of an object does not impact its density, i.e., the density of an object will not change if you cut the object into pieces.


  • Three different candy bars of your choice (Snickers, Crunch, Milky Way, etc.).
  • Rulers
  • Scale
  • Knife
  • Calculator

To unlock this lesson you must be a Member.
Create your account

Register to view this lesson

Are you a student or a teacher?

Unlock Your Education

See for yourself why 30 million people use

Become a member and start learning now.
Become a Member  Back
What teachers are saying about
Try it risk-free for 30 days

Earning College Credit

Did you know… We have over 200 college courses that prepare you to earn credit by exam that is accepted by over 1,500 colleges and universities. You can test out of the first two years of college and save thousands off your degree. Anyone can earn credit-by-exam regardless of age or education level.

To learn more, visit our Earning Credit Page

Transferring credit to the school of your choice

Not sure what college you want to attend yet? has thousands of articles about every imaginable degree, area of study and career path that can help you find the school that's right for you.

Create an account to start this course today
Try it risk-free for 30 days!
Create an account