# This lesson asks the question “Will the boat sink or float?”

Subject:

Science

4

Title – Will it Float or Sink?
By – Carolyn Currins
Primary Subject – Science

“Ship Shape” Science Center
Will it float or sink? How much will it hold?

Purpose: To determine whether certain objects will float or sink and design a boat that will float and hold weight.

Materials:

• Aluminum foil — flat sheets exactly the same size
• Container for water
• Water
• Pennies
• Marker

Procedures:

1. Fill a container with water.
2. Take two pieces of aluminum foil — put a penny in the middle of one and tightly form it into a ball; lay the other piece flat and put a penny in the middle of it.

How are the two pieces of foil alike? How are they different? (Comparison Question)
What do you think will happen when the flat sheet & penny is placed in the water? (Action Question)
What do you think will happen when the ball of foil with the penny is placed in the water? (Action Question)

3. Place the flat sheet with the penny on the surface of the water.

What do you observe? (Attention Focusing)
Why do you think this happened? (How and Why Question/Reasoning Question)

4. Place the ball with the penny in the water.

What do you observe? (Attention Focusing)
Why do you think this happened? (How and Why Question/Reasoning Question)

5. Take the flat sheet and penny out of the water and bend the edges up to form a boat. Be sure to seal the edges tightly so it does not leak.
6. Gently place the boat in the water.

What happens to the foil boat? (Attention Focusing)
Why do you think this happens? (How and Why Question/Reasoning Question)

How many pennies do you think your boat can hold before sinking? (Measuring Question)

8. Slowly add weight (pennies) to your boat a little at a time.

How does the amount of pennies your boat held before sinking compare to your prediction? (Comparison Question)

10. Use another piece of foil to build another boat.

Can you build a boat that will hold more weight (pennies)?
What will you do differently and why? (Problem Posing)
Should the boat be wider? Taller? Longer? (Problem Posing)

11. Float your second boat in the water.

How many pennies did your boat hold before sinking? (Measuring Question)
How does the amount of pennies compare to your first boat? (Comparison Question)
What can you determine about the size and shape of objects in water and whether they float or sink? (Reasoning Question)

Explanation:

The flat piece of aluminum and the balled up aluminum have the same weight. However, the ball takes up a smaller space than the flat sheet. When the ball is put into the water, the ball pushes less water out of its way than does the pan. The amount of water pushed aside or “displaced” by an object equals the amount of force that the water pushes upward on the object. If there is not enough upward force by the water, then the object will sink. For the aluminum ball, there was not enough upward force by the water so it sank. The larger flat sheet floated because it pushed aside more water and there was enough upward force to cause it to float.
Even though large ships are heavy, their shape displaces large amounts of water and the upward force from the water keeps them afloat. They also have hollow compartments filled with air, which increases their buoyancy.

Student Evaluation:

• Students will be asked to predict whether the foil pieces will float or sink.
• Students will create a boat using one piece of aluminum foil.
• Students will be asked various questions throughout the experiment to check for understanding and to encourage involvement in learning.

Bibliography/References:

Abruscato, Joseph. Teaching Children Science: Discovery Methods for the Elementary and Middle Grades. Boston: Allyn and Bacon, 2004.