Topic-
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Exploring Buoyancy-Students will understand the terms buoyancy,
density, and displacement
- How boats float
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Goals: Aims/Outcomes-
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Students will understand that a Buoyant Force is an upward force
exerted by a
fluid on a floating or submerged object.
Students will understand and demonstrate the difference between positive
buoyancy, negative buoyancy and neutral buoyancy.
3) Students will understand and apply the key concepts of: buoyancy,
density, and
the balancing of forces to solve a design challenge. |
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Objectives-
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Students will know that density is mass per unit volume
Students will be able to predict whether an object will float or sink.
Students will be able to reshape an object so that it will float,
instead of sink, to come to understand that the buoyant force of an
object is an upward force.
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Materials and Aids-
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| Small plastic boat, a container of water, pennies, clay, a balloon
and a rubber ball. |
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Procedures/Methods-
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Practice-
Task 1. Density
- Examine the various objects on display for this assignment. Why
do objects that are the same size sometimes have different weights?
Explain why.
Task 2. Displacement
- Float a blown-up balloon on the water. It doesn't sink very far
because...? Do you notice anything different with he water?
- Float a ball the same size as the balloon. Does it sink deeper into
the water?
- Float a small plastic boat in water and notice how deep the boat
sinks when it is empty.
- Drop a penny in the boat. Does the boat sink deeper in the water?
Add a few pennies to the boat and watch what happens.
Add more pennies until the boat sinks. Why did the boat sink?
Task 3. Buoyancy
A ship will float as long as it weighs less than the water it displaces.
Ships
can hold materials in their hulls that are heavier than water, but
there must be air within the ship.
- Roll the clay into a ball and place it in the container. What happens?
- Now shape the clay into a bowl, put it in the water with the open
part of the bowl facing up so it stays filled with air. What happens?
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