Skip to main content

Density Mission (Save Paul the Ping-Pong Ball)

Paul the Ping-Pong Ball

Physical Science Activity: Liquid Flax

A simple density activity that shows items can sink or float in materials other than water. (Density is the amount of stuff (matter) in an object. Density = mass/volume (d = m/v))

To introduce the activity have the students watch the following videos.

Liquid Flax can be presented as a standalone class demonstration or it can be expanded into a class activity, depending on the amount of time available. I usually present this demonstration as a science magic trick. I announce that I will place a metal ball into a bucket of beans/flax and make it disappear. The demonstration is shown in the videos below and also described in the following lesson plan. (Lesson Plan - PDF and Demo Card: Demo Card - PDF)

Expand the Demonstration:

Try different grains.
Test other items to see whether they sink or float in your grain of choice.

Agriculture Related Topic: Grain Bin Hazards

Suffocation Hazards Grain Bins (University of Arkansas)

Related Activities

Physical Science Demonstration: Liquid Flax (Educator Explanation)

Physical Science Demonstration: Liquid Flax