--- title: Floating and Sinking | Explore Density and Buoyancy | KnowAtom description: Explore the science of floating and sinking through hands-on activities and lessons on density, buoyancy, and how shape affects objects in water. --- More Lessons for Your State Alabama Alaska Arizona Arkansas California Colorado Connecticut Delaware Florida Georgia Hawaii Idaho Illinois Indiana Iowa Kansas Kentucky Louisiana Maine Maryland Massachusetts Michigan Minnesota Mississippi Missouri Montana Nebraska Nevada New Hampshire New Jersey New Mexico New York North Carolina North Dakota Ohio Oklahoma Oregon Pennsylvania Rhode Island South Carolina South Dakota Tennessee Texas Utah Vermont Virginia Washington Washington DC West Virginia Wisconsin Wyoming Other NGSS # Floating and Sinking In the last unit, students used propeller cars to explore the relationship between forces and motion. In this unit, students continue to explore vehicles with a focus on boats and specifically the science phenomena of properties that cause objects such as boats to float or sink. This page showcases parts of each element of the first lesson in this unit. 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In this unit, students explore density by exploring what properties of objects make them float or sink.  Density is the amount of matter packed in a certain amount of space. In other words, it is a measure of the amount of mass in a given volume. Volume is the measure of how much space a substance takes up. The more tightly packed the molecules of an object are, the denser they are. This is because they have more mass in a given volume than materials that are less dense. Objects float when they are less dense than the fluid they are in. For example, salt water produces a greater buoyant force than fresh water because salt water is much denser than freshwater. This is why objects float more easily in salt water than in fresh water, and why a bowling ball floats in the Dead Sea. The shape of the object also affects its buoyancy because the more surface area an object has, the more water it displaces and the more the water pushes back. This helps the object float. #### Supports Grade 2 ![Sneak Peek Seal with Arrow](https://www.knowatom.com/hubfs/Sneak%20Peek%20Seal%20with%20Arrow.svg) ## Science Lesson: Comparing Floating and Sinking In this lesson, students investigate how objects float or sink depending on their density and then investigate how changing the shape of an object can affect whether it floats or sinks. [Download a Sample Unit ](https://www.knowatom.com/stem-curriculum#state) ## Science Big Ideas - Materials have different properties and certain properties can make a material useful for a particular function.  - Density is important for determining whether an object will float or sink.  - The shape of an object matters in determining whether it floats or sinks.  ![sample unit-k8 science curriculum-knowatom](https://www.knowatom.com/hs-fs/hubfs/Sample%20Unit%20CTA-2.png?width=327&height=264&name=Sample%20Unit%20CTA-2.png) ###### Discover Complete Hands-on Screens-off Core Science Curriculum for K-8 Classrooms Prepared hands-on materials, full year grade-specific curriculum, and personalized live professional development designed to support mastery of current state science standards. [Click Here to Learn More](https://www.knowatom.com/talk-to-knowatom-sales) ## Science Essential Questions - What properties of matter determine whether an object floats or sinks? - Why is density a property of matter? - Why would a bowling ball sink in fresh water but a beach ball float in the same water? - How does changing the shape of an object affect whether it floats or sinks in water? ## Common Science Misconceptions ![close-circle-red](https://www.knowatom.com/hubfs/Icon%20ionic-ios-close-circle-red-1.svg) **Misconception:** All big objects sink, while little objects float. ![checkmark-circle-green](https://www.knowatom.com/hubfs/Icon%20ionic-ios-checkmark-circle-green.svg) **Fact:** The most important factor in whether an object floats or sinks is its density. An object’s density is determined by the materials that make it up and its volume. ![close-circle-red](https://www.knowatom.com/hubfs/Icon%20ionic-ios-close-circle-red-1.svg) **Misconception****:** The shape of a boat is unrelated to how well it can stay afloat. ![checkmark-circle-green](https://www.knowatom.com/hubfs/Icon%20ionic-ios-checkmark-circle-green.svg) **Fact:** A boat’s shape plays a major role in how buoyant the boat will be. Other factors that influence buoyancy include size and the materials of the boat. ## Science Vocabulary **Density :** a property of matter; the amount of matter packed in a certain amount of space **Float :** to stay above the surface of water or another fluid such as air **Sink : ** to drop down in water or another fluid such as air ## Lexile(R) Certified Non-Fiction Science Reading (Excerpt) **Floating in the Dead Sea** The Dead Sea is a body of water. People come from all over the world to visit it. It is famous because it is very salty. It is much saltier than the ocean. People float easily in the Dead Sea. To float means to stay above the surface of water or another fluid such as air.   **Density and Floating** Objects float when they are less dense than the fluid they are in. Density is a property of matter. It is the amount of matter packed in a certain amount of space. The particles of a dense object are packed tightly together. The particles of a less dense object have more space around them. Salt water is denser than fresh water. There are more particles in a cup of salt water than there are in a cup of fresh water. Both cups of water have the same amount of water. But fresh water doesn’t have many particles of salt. ![floating-and-sinking](https://www.knowatom.com/hs-fs/hubfs/floating-and-sinking.jpg?width=261&height=340&name=floating-and-sinking.jpg) ![floating-and-sinking1](https://www.knowatom.com/hs-fs/hubfs/floating-and-sinking1.jpg?width=261&height=340&name=floating-and-sinking1.jpg) ![floating-and-sinking2](https://www.knowatom.com/hs-fs/hubfs/floating-and-sinking2.jpg?width=261&height=340&name=floating-and-sinking2.jpg) ## Hands-on Science Activity For the hands-on activity in this lesson, students investigate how objects float or sink depending on their density and then investigate how changing the shape of an object can affect whether it floats or sinks. In the first part of the investigation, students analyze the properties of different objects and then drop the objects into a water-filled test container to see if they float. In the second part of the investigation, students mold a clay ball into a shape that can float in the water. Students use the data they gathered from both parts of the investigation to construct an explanation about how the properties of an object affect whether it floats or sinks in water. [ Learn More About KnowAtom ](https://www.knowatom.com/stem-curriculum) ## Science Assessments KnowAtom incorporates formative and summative assessments designed to make students thinking visible for deeper student-centered learning. - Vocabulary Check - Lab Checkpoints - Concept Check Assessment  - Concept Map Assessment  - And More... [Download a Sample Unit ](https://www.knowatom.com/stem-curriculum#state) ![engineering-boats-assess-1](https://www.knowatom.com/hs-fs/hubfs/engineering-boats-assess-1.jpg?width=281&height=388&name=engineering-boats-assess-1.jpg) ![alabama state standard](https://www.knowatom.com/hs-fs/hubfs/Alabama-State-Standards-Alignment-1.png?width=540&height=402&name=Alabama-State-Standards-Alignment-1.png) ###### See How KnowAtom Aligns to NGSS Science Standards Discover hands-on screens-off core science curriculum for student centered K-8 classrooms. KnowAtom supports classrooms with all hands-on materials, curriculum, and professional development to support mastery of the standards. [Download the Alignment to NGSS](https://www.knowatom.com/stem-curriculum) ** Standards Tags: ** [2-PS1-2](https://www.knowatom.com/2-ps1-2) , [2.3.1](https://www.knowatom.com/2.3.1) , [2.3.2](https://www.knowatom.com/2.3.2) , [2.PS2.2](https://www.knowatom.com/2.ps2.2) , [SKP1](https://www.knowatom.com/skp1) , [SKP2](https://www.knowatom.com/skp2) , [S2P1](https://www.knowatom.com/s2p1) , [1.P2U1.3](https://www.knowatom.com/1.p2u1.3) , [2P.1.1.1.1](https://www.knowatom.com/2p.1.1.1.1) , [2P.2.2.1.1](https://www.knowatom.com/2p.2.2.1.1) , [2.PS1.A.2](https://www.knowatom.com/2.ps1.a.2) , [3.2.2.B](https://www.knowatom.com/3.2.2.b) , [2.PS.1](https://www.knowatom.com/2.ps.1) , [K.PS.1](https://www.knowatom.com/k.ps.1) , [Asking questions and defining problems](https://www.knowatom.com/asking-questions-and-defining-problems) , [Planning and carrying out investigations](https://www.knowatom.com/planning-and-carrying-out-investigations) , [Analyzing and interpreting data](https://www.knowatom.com/analyzing-and-interpreting-data) , [Constructing explanations and designing solutions](https://www.knowatom.com/constructing-explanations-and-designing-solutions) , [Engaging in argument from evidence](https://www.knowatom.com/engaging-in-argument-from-evidence) , [Obtaining evaluating and communicating information](https://www.knowatom.com/obtaining-evaluating-and-communicating-information) , [Structure and Properties of Matter](https://www.knowatom.com/structure-and-properties-of-matter) , [Cause and Effect](https://www.knowatom.com/cause-and-effect) , [Matter and Its Interactions 2](https://www.knowatom.com/matter-and-its-interactions-2) , ### Supports Grade 2 #### Science Standards - [2-PS1-2](https://www.knowatom.com/2-ps1-2) - [2.3.1](https://www.knowatom.com/2.3.1) - [2.3.2](https://www.knowatom.com/2.3.2) - [2.PS2.2](https://www.knowatom.com/2.ps2.2) - [SKP1](https://www.knowatom.com/skp1) - [SKP2](https://www.knowatom.com/skp2) - [S2P1](https://www.knowatom.com/s2p1) - [1.P2U1.3](https://www.knowatom.com/1.p2u1.3) - [2P.1.1.1.1](https://www.knowatom.com/2p.1.1.1.1) - [2P.2.2.1.1](https://www.knowatom.com/2p.2.2.1.1) - [2.PS1.A.2](https://www.knowatom.com/2.ps1.a.2) - [3.2.2.B](https://www.knowatom.com/3.2.2.b) - [2.PS.1](https://www.knowatom.com/2.ps.1) - [K.PS.1](https://www.knowatom.com/k.ps.1) - [Asking questions and defining problems](https://www.knowatom.com/asking-questions-and-defining-problems) - [Planning and carrying out investigations](https://www.knowatom.com/planning-and-carrying-out-investigations) - [Analyzing and interpreting data](https://www.knowatom.com/analyzing-and-interpreting-data) - [Constructing explanations and designing solutions](https://www.knowatom.com/constructing-explanations-and-designing-solutions) - [Engaging in argument from evidence](https://www.knowatom.com/engaging-in-argument-from-evidence) - [Obtaining evaluating and communicating information](https://www.knowatom.com/obtaining-evaluating-and-communicating-information) - [Structure and Properties of Matter](https://www.knowatom.com/structure-and-properties-of-matter) - [Cause and Effect](https://www.knowatom.com/cause-and-effect) - [Matter and Its Interactions 2](https://www.knowatom.com/matter-and-its-interactions-2) [![New call-to-action](https://no-cache.hubspot.com/cta/default/347944/b5a1446e-d782-4a5f-a019-0b3b98c8304f.png)](https://cta-redirect.hubspot.com/cta/redirect/347944/b5a1446e-d782-4a5f-a019-0b3b98c8304f) Standards citation: NGSS Lead States. 2013. Next Generation Science Standards: For States, By States. Washington, DC: The National Academies Press. 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