Sink or Float: Discovering Buoyancy!

Science Grades 2nd Grade 1:13 Video
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Lesson Description

Learn about buoyancy, density, and why some things float while others sink! This lesson uses a fun video to explore these important science concepts.

Video Resource

What is buoyancy?

The Children's Hands-On Museum of Tuscaloosa

Duration: 1:13
Watch on YouTube

Key Concepts

  • Buoyancy
  • Density
  • Float vs. Sink

Learning Objectives

  • Students will be able to define buoyancy as a force that makes objects float.
  • Students will be able to explain that density determines whether an object will sink or float.
  • Students will be able to identify whether an object is more or less dense than water based on its behavior (sinking or floating).

Educator Instructions

  • Introduction (5 mins)
    Begin by asking students what they already know about floating and sinking. Show them a few everyday objects (e.g., a small rock, a piece of wood, a coin, a plastic toy) and ask them to predict whether each will sink or float in water. Briefly discuss their predictions.
  • Video Viewing (3 mins)
    Play the YouTube video "What is buoyancy?" from The Children's Hands-On Museum of Tuscaloosa. Remind students to pay attention to the key concepts of buoyancy and density.
  • Discussion (5 mins)
    After watching the video, facilitate a class discussion using the discussion questions below.
  • Interactive Exercise: Sink or Float Experiment (15 mins)
    Conduct a simple sink or float experiment. Provide students with a variety of objects (e.g., paper clip, cork, grape, small plastic block, aluminum foil ball, small pebble). Have them predict whether each object will sink or float, then test their predictions in a tub of water. Record the results on a class chart. Discuss any surprises or unexpected outcomes.

Interactive Exercises

  • Sink or Float Experiment
    Students predict and test whether various objects sink or float, recording their observations and discussing the results in terms of density.
  • Density Sorting
    Provide a set of pictures or small objects and have students sort them into two categories: 'More Dense' (likely to sink) and 'Less Dense' (likely to float).

Discussion Questions

  • What is buoyancy?
  • What is density? How does it affect whether something sinks or floats?
  • What are some examples of things that float? What are some examples of things that sink?
  • Can you think of a time when buoyancy is helpful?

Skills Developed

  • Observation
  • Prediction
  • Data Collection
  • Critical Thinking

Multiple Choice Questions

Question 1:

What is buoyancy?

Correct Answer: A force that makes things float

Question 2:

What is density?

Correct Answer: How close the tiny parts of something are packed together

Question 3:

If something is more dense than water, will it usually...

Correct Answer: Sink

Question 4:

If something is less dense than water, will it usually...

Correct Answer: Float

Question 5:

A boat is hollow and filled with air. Will it probably...

Correct Answer: Float

Question 6:

Which of these will probably sink in water?

Correct Answer: A rock

Question 7:

Which of these will probably float in water?

Correct Answer: A balloon filled with air

Question 8:

What are the tiny parts that make up everything called?

Correct Answer: Atoms and molecules

Question 9:

Which of these is a force?

Correct Answer: Buoyancy

Question 10:

Miss Laura taught us about...

Correct Answer: Buoyancy

Fill in the Blank Questions

Question 1:

__________ is a force that makes things float.

Correct Answer: Buoyancy

Question 2:

How close the tiny parts are packed together is called __________.

Correct Answer: Density

Question 3:

If something sinks, it is more __________ than water.

Correct Answer: Dense

Question 4:

If something floats, it is less __________ than water.

Correct Answer: Dense

Question 5:

Atoms and __________ make up everything.

Correct Answer: Molecules

Question 6:

A boat floats because it is filled with ___________.

Correct Answer: Air

Question 7:

A rock sinks because it is __________.

Correct Answer: Dense

Question 8:

Air pressure is a ___________.

Correct Answer: Force

Question 9:

Gravity is a ___________.

Correct Answer: Force

Question 10:

We learned about buoyancy from Miss __________.

Correct Answer: Laura

Educational Standards

2.PS1.1:[Standard] Plan and conduct an investigation to describe and classify different kinds of materials by their observable properties. 2.PS1.2:[Standard] Analyze data obtained from testing different materials to determine which materials have the properties that are best suited for the intended purpose.*

Teaching Materials

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