Eighth graders learn density — how much mass is packed into a given volume — and use it to predict whether an object floats or sinks, discovering that a huge steel ship floats while a tiny pebble sinks.
Students will be able to…
A giant steel ship floats, but a tiny pebble sinks. How can something so heavy float while something so light goes straight down? The secret is density.
Project this and change the mass and volume. Watch the density change — and see whether the object floats or sinks in water!
Tap any phase to open the teacher moves and student actions.
A steel ship floats but a pebble sinks — how?
Students investigate.
Students explain.
Students elaborate.
Students conclude.
Aligned to the Next Generation Science Standards (Middle School Physical Science).
Develop models to describe the atomic composition of substances.
Analyze data on properties of substances (like density).
Model changes in particle motion and arrangement.
Using mathematics and computational thinking.
Preview the three formative checks. Tap “Sample answer” to see what mastery looks like — hide them before you print for students.
Have students investigate why ice is LESS dense than liquid water — an unusual and important property that lets fish survive under frozen lakes. A printable density sheet is in the Science library.
Tap a card to flip it, then rate whether you knew it. Built from this lesson’s vocabulary.
A quick self-check with instant feedback, drawn from this lesson’s key terms.
A print-and-go review sheet with a built-in answer key. Tap “Show answer key” to reveal answers, or print the clean version for students.