Directions:

1. Think about and write down ideas

• • Why might a boat not float well?

  • Will your boat be a platform, like a raft, or an open boat, like a canoe?

  • How will you waterproof your boat?

  • How big will your boat need to be to hold the pennies?

  • TIP: When engineers solve a problem, they try different ideas, learn from mistakes, and try again. The steps they use to arrive at a solution are part of the design process.

2. Look at the materials

• • What materials do you have to build the boat?

  • What materials do you have to waterproof the boat?

  • What will you use to balance the pennies so they don’t fall into the water?

  • TIP: A boat can get tippy when one part is heavier than another.

3. Design and build the boat

• • Decide how you will construct the boat so it will stay afloat when you add weight to it.

  • Think about the size and shape you want to make your boat.

  • Choose your boat materials and build the boat.

  • TIP: The width and height of a boat’s sides can affect its buoyance in the water.

4. Waterproof the boat

• • Decide what materials will keep the water out of your boat so it will stay afloat.

  • Choose the materials and waterproof the boat.

5. Test the boat before adding weight

• • Place the boat in the water to test its ability to float.

  • Leave it in the water for about a minute.

  • TIP: If the boat sinks, the waterproof seal is not tight. Try finding the leak by pushing the boat in the water and watching for bubbles to surface. Or check all openings and seal them tightly.

  • TIP: You can test a design at different steps along the building process. This way you can spot a problem and fix it when it happens instead of at the end of the process.

6. Make the weight holder (if you decide to include one)

• • Decide whether or not your boat will have a container to hold the pennies.

  • Decide what materials you will use to hold the pennies.

  • Make the holder and attach it to the boat.

7. Load up your boat

• • Place your boat in the water.

  • Put the pennies in your boat. Add them carefully one at a time.

  • TIP: If your boat is tipping over, make sure the weight is well distributed. Spread the weight evenly across the bottom of the boat.

  • TIP: A boat can tip when the load is up high. Place pennies in the lowest part of the boat.

8. Time test the boat

• • Set a timer or look at a clock’s second hand. Test whether your boat can stay afloat for 10 seconds or longer.

  • TIP: If the boat can’t support 25 pennies, try increasing its buoyancy by increasing the container’s size and depth.

  • TIP: If the boat won’t stay afloat, try building a boat with a V-shaped hull. This is generally a more stable design then a flat-bottomed boat.