Marie Curie Math & Science Center

Harriet Yustein, RP Connor School, 3B

Science (Buoyancy) Third Grade

Students will be informally introduced to the concept of buoyancy by planning and constructing their own floating containers. Students experiment with a variety of materials and designs to investigate the variables that affect the floatation of their boats. The skills emphasized in buoyancy are collecting data, manipulating, observing and predicting.

Commencement content standard from MST (one or more of the seven):

Standard 4: Science

Students will understand and apply scientific concepts, principles, and theories pertaining to the physical setting and living environment and recognize the historical development of ideas in science.  


Benchmark standards:

Content standards (what you want your students to know or be able to do)

Elementary Students

Physical Setting Benchmark 2: Many of the phenomena that we observe on Earth involve interactions among components of air, water and land

Performance standards (how you will know that they know--how good is good enough)

Describe the relationships among air, water and land on Earth 

Content standards or outcomes for your unit: Be sure to identify all the constructs you will be assessing. They should help your students achieve the above


1. Students will explore the properties of classroom materials that sink and float.

2. Students will understand that the shape of an object will affect its ability to float.

3. Measure and compare compacity of clay boats by amount of cargo it can hold.

4. Identify variables that affect buoyancy.

5. Students will observe that objects are more buoyant in heavier liquids. 

Performance measures for your unit:


4 3 1
Student is able to construct a boat that floats indefinitely Student is able to construct a boat that floats Student constructs a boat that sinks within minutes Students construct a boat that sinks instantly


Student accurately places 100% of weights in order for it to float


Student places 75% of weights in order for it to float Student places 50% of weights in order for it to float Students placement is totally inaccurate
Student can explain clearly and in detail how the boat floats Student can generally explain how the boat floats Student has some difficulty with his explanation of how the boat floats Student can not give an explanation of how the boat floats


Enabling Activities:

Describe each day's activity separately or holistically plan for ten days of work. Include all parameters of the setting including grouping, space, time and props. Include some critical directions and questions for the classroom dialogue or attach a worksheet of activity directions. (See Chapter 6)

Day One: Floating and Sinking Objects - students group objects according to buoyancy and discuss attributes. Graph on chart paper or overhead. Discuss in small groups why some floated and some did not. Then have a whole group discussion.

Day two - Using balls of clay see if it floats and then try to make it float. Determine the characteristics of the boat that floated. Draw picture of what floated and what sank for them.

Day three - Have students predict the amount of uniform weights that will fit in the boat they made. Use Excel to make a chart of the number of weights the boat carried.

Day four - Give two pieces of aluminum foil and see if they can make it sink and make it float.

Test capacity. Test predictions and record data.

Day five - Read Curious George Rides a Bike by Rey. Follow directions to make a boat from newspaper. Test floating them. Hand out information about a project for them to make a boat. It will be due in five days. Have them name the boat, what type of boat it is. Ask for volunteers to bring in a baby pool etc. to use to float the boats.

Day six - Test a variety of liquids - hot water, cold water, salty water, soapy water, mineral oil etc. Put small medicine cups in the different liquids and test the buoyancy with and without the weights. Compare this with the previous data obtained by using regular water.

Day seven - Make a hydrometer using straw, clay and dirt. Test the density of the water.

Take separate cups with oil, alcohol and water in each of the separate cups. Combine them into one cup one at a time. Add food coloring to the cups. This will help the children see the densities of the liquids.

Day eight - Make a cartesian diver showing how air helps something float.

Day nine - Use Encarta to research famous boats such as the Mayflower and the Titanic.

View science video on buoyancy.

Day 10 - Test boats made for their project and fill them with weights to see which boat holds more. Have the children explain the process that they used in making this particular boat so that it floated. (see rubric)

Culminating trip - Intrepid Air and Space Museum in New York City

Related web sites:


St. Thomas Aquinas College, 125 Route 340, Sparkill NY 10976-1050