Foundations of Physical Science

Workshop: Buoyancy

Presenters Patsy DeCoster Director of Staff Development patsy@cpo.com

Scott Eddleman Manager of Curriculum Development scott@cpo.com

CPO Science Inquiry-based textbook programs

Foundations of Physical Science Foundations of Physical Science with Earth and Space

Science Introduction to Earth and Space Science Foundations of Physics COMING IN 2005: Chemistry

Supplemental hands-on equipment and curriculum for grades 6 – 12

Staff Development Graduate institutes Workshops Videos/DVDs

Hands-on Equipment

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Key Questions Why don’t boats

made of steel SINK?

Is it possible for a material that is MORE DENSE than water to float?

Overview Use clay instead of steel

Make measurements and observations of clay stick

Build a clay boat

Make measurements and observations of clay boat

Set up your work area Use wax paper to cover work area

Web participants that registered in advance received a materials list, those of you that are here with me have all the materials you need at your table. There is enough clay for each person to build his/her own boat, but we will share non-consumables such as graduated cylinders.

Find volume of clay stick in cubic cm, mass in grams, and then calculate density. (see data summary next slide)

Will the clay sink or float?

Test your hypothesis. Place clay stick in container of water to see if it floats or sinks. Remove clay quickly and dry it off!

Does Clay Sink or Float?

Length (cm)__________

Width (cm)___________

Height (cm)__________

Volume (cm3)__________

Mass (g)______________

Density (g/cm3)___________

SINK OR FLOAT?

Clay Stick

Questions?

Place clay stick carefully into displacement tank. Be sure a dry beaker is under the overflow spout!

Use the graduated cylinder to measure the volume of water displaced.

How does the volume of displaced water compare to first volume measurement of clay stick?

Volume of clay stick in mL

Discussion/Questions

Find mass of displaced water. How does this value compare to the volume?

Now calculate the WEIGHT of displaced water. (why calculate weight? Because we want to look at FORCES involved with floating and sinking)

Calculate the weight of the stick of clay

Floating and Sinking and Forces…

Volume of displaced water (ml)__________

Mass of displaced water (g)_________

Weight of displaced water (N)________

(gramsX0.0098N/g = N)

Weight of clay stick (N)_____________

Clay Stick

Clay Stick Data SummaryWeight (N) of object

Volume (mL) of displaced water

Weight (N) of displaced water

Stick of Clay

0.58 N 36.0 mL 0.35 N

Clay Boat

Make a Boat! Use the entire stick of clay to mold the clay

into a shape that will float. You will be putting the boat in the displacement tank, so be sure that it fits properly.

PREDICT: How will weight of boat, volume of displaced water, and weight of displaced water compare to the data for the clay stick?

Use the displacement tank to find out how much water the boat displaces

Find the weight of the displaced water

Conclusions Study the data. What relationships can

you see among the measured values?

Weight (N) of clay

Volume (mL) of displaced water

Weight (N) of displaced water

Stick of Clay

0.58 N 36.0 mL 0.35 N

Clay Boat 0.58 N 60.0 mL 0.58 N

Thank You!

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