About This Lesson
SCIENCE – Teach students about buoyancy by conducting a sink or float experiment, then use engineering skills to build a Lego boat and try to make it float.
Learning Objectives:
With Buoyancy with Lego Boats, students will learn to experiment and test, make predictions, sort and categorize objects, observe and describe what happens, record data using graphs or charts.
Materials needed:
- Random objects for students to test if they sink or float
- A container filled with water
- Download the student chart to track their designs and progress
- Assorted Legos for students to build their boats
- Pennies to test the density
Begin by explaining the following scientific principles:
Objects that float are positively buoyant and there are several reasons why they float. Objects that are less dense than water will float. Density refers to how close together the molecules of an object are. For example, most rocks sink in water because they are denser than water. Also, the surface (i.e., the outside of an object) that touches the water displaces it, or pushes it out of the way.
The shape of an object also affects how water moves around the object’s surface. For example, the shape of a boat creates a large surface for water to push against. However, if too much weight is added to a boat, it will sink beneath the water. (Students will test this after they construct their Lego boat by adding pennies.)
Some objects are neutrally buoyant. This means that they sink beneath the water’s surface, but they do not sink all the way to the bottom. This happens when an object’s density is the same as the density of the water it is in.
Education Standards
Next Generation Science Standards
ENGINEERING: K • K-2-ETS1-1 • K-2-ETS1-2 • K-2-ETS1-1
