Building Boats

Filed Under (Science) by on March 10, 2011 and tagged ,

Our new science unit is all about Properties of Matter. Properties of matter are the ways that we can describe matter. Some physical properties of matter are: weight, texture, color, absorbency, transparency, and many others.

We did a science activity to investigate the property of Buoyancy: if an object sinks or floats.

Bouyancy - Sink or Float

Buoyancy – Sink or Float

Mr. Salsich gave partners a limited amount of materials to try to build a boat that could float and also hold marbles. We tried to see how many marbles our boats could hold without sinking. Here are the materials we were given:

4 rubber bands, 4 straws, 6 popsicle sticks, a stick of clay, and a 6x12 inch shhet of alumimum foil

4 rubber bands, 4 straws, 6 Popsicle sticks, a stick of clay, and a 6 x 12 inch sheet of tin foil

We didn’t have to use all the supplies, but these were the only materials we could use.

Here is a video showing what we did and what we learned.


(Special thanks to Tommy’s mom for helping test the boats!)


Have you ever done a “sink or float” experiment?

How do scientists learn?

Some students said the tin foil floated because it was light. How do heavy, steel ships float?

What was your favorite part of the activity?

23 Responses to “Building Boats”

  1.   Learning Together Says:

    Hello Mr Salsich’s Class,

    My students in Prep (5/6 year olds) were wondering about sinking and floating just yesterday! We made a list of things we thought would sink and ones that would float. Then we tested our ideas. We discovered that the heavy objects sunk and light objects floated. When we put a piece of paper in the water it floated and then it sank very slowly. I wonder why?

    Your boats look fantastic and I loved seeing you work so well together in your teams.
    You made some great discoveries.

    Thank you for sharing.

    From Mrs Kennedy and Prep K


  2.   Emmett Says:

    Dear Mr. Salsich,

    I can’t believe that our group got 78 marbles!
    My favorite part of the activity was getting our ideas together and actually getting the boat built.

    Emmett in Mr. Salsich’s Class


  3.   Menghan Xu Says:

    This was an interesting science class.


  4.   Mr. Avery Says:

    Dear Mr. Salsich,

    You have some very impressive engineers in your class! I’m not sure that I could build a boat using those materials that would hold 78 marbles!

    That was a great lesson about materials that sink or float. Living close to the coast, I’m sure many of your students have been to the ocean and seen some very buoyant things. What have any of you ever seen in the water at the beach that is buoyant?

    Keep up your great work!

    Mr. Avery


    •   Mr. Salsich Says:

      Dear Mr. Avery,

      Thank you for that wonderful comment!

      We have seen lots of things that are buoyant around our town. One thing is a buoy. Some jellyfish seem to float. Life jackets are very buoyant! Lots of seaweed floats, especially the kind that has sacs of air that you can pop! And of course, boats!

      Thanks again for the comment. Are you close to the shore also?

      Mr. Salsich’s class


      •   Mr. Avery Says:

        Dear Mr. Salsich’s class,

        We are very close to the shore! Our school is about 10 minutes from the ocean. When it gets warmer, a lot of students will start going to the beach. There they might see other buoyant objects like wakeboards, surfboards, or tennis balls!

        Thanks for writing back!

        Mr. Avery


  5.   Taylor Says:

    Dear Mr. Salsich,

    It was very fun making the boats. The first time we did the boat building my boat held 69. Today we did it today ours held 70 something. Another person in our class held 200 which was all of the marbles that you had! It was hard trying to pick what stuff to use to make the boat.

    Happy Blogging!

    Taylor :)


  6.   David Says:

    This is one of my favourite posts, I am still however recovering from my first experience of Juan Pablo!
    I very much enjoyed the social interactions between the children. You chaps collaborate really well. I thought the comment about enjoying having ‘no instructions’ was valid.
    I am always surprised that you don’t have uniforms.
    The technical work was impressive … please could you tell me what software you were using?
    Class challenge … using just modeling clay, we call it plasticine. A rolled up lump of plasticine sink, like a stone. Using just the plasticine can you make it float ?… Can it carry marbles?

    A very impressed
    Mr E
    Hawes, England


  7.   Margot Says:

    Dear Mr. Salsich,

    I liked our boats. It was funny when I accidentally ripped the tin foil! It was very fun making the boats because it was intersting to try your boat the first time and then realize which materials were the best.

    Sponges sometimes would float, but sometimes sink and they were a little unpredictable. The clay was heavy and absorbed water. The straws would get filled with water and they would sink, and if you plugged them with clay they would weigh the boat down.

    The popsicle sticks and the tinfoil were helpful because the wood would float no matter what, and the tinfoil would be rolled up at the sides which caught air and kept the boat afloat.



    •   Mr. Salsich Says:

      Dear Margot,

      Great comment about how the different materials were more or less useful when making the boats. You are right, a lot of it has to do with weight and absorbency and also the shape of the boat. Excellent scientific thinking!

      Mr. Salsich


  8.   Alexandra Says:

    Dear Mr. Salsich,

    I thought that boat building was a very fun experiment. Me and Maggie’s first boat only held 20 marbles but our second boat held 78 and the next time we made them it held 145!

    I liked to see all of the other people’s boats and what they did that might make ours better, for instance we watched Emmett and his partners and when they made a boat completely out of tin foil and how it held so many marbles so we did the same thing.

    *Alexandra :- )


    •   Mr. Salsich Says:

      Dear Alexandra,

      Thanks for a great comment! You obviously learned a lot about what materials and designs to use for your boat because you got more and more marbles each time – 145 is a lot!

      Scientists are always paying attention to what other scientists do and getting ideas from what worked and didn’t work. Great job learning from what other groups did!

      Mr. Salsich


  9.   Cassie's dad Says:

    Dear Mr. Salsich and class,

    I think that was a very good post! I know it is fun to make boats because I like to make boats with Cassie. What was your favorite part of making the boats? Your video was fantastic! I liked when Cassie’s group ripped the tin foil that was very funny!

    Cassie’s dad


  10.   Moira Casadei Says:

    What fun it is to make “something” from “nothing!! The trial and errors of your own inventions sure made the boats improve as the video progressed. Great job; boat creators, scientists, logical thinkers and cooperative teams!!
    Loved the background music that added suspense and the fast speed to show more activity……your video productions are “top shelf”!!
    Sam C.’s Grandma


  11.   Mrs. Watson Says:

    Dear Mr. Salsich’s Class,
    I can’t begin to tell you how much I enjoyed watching your video. I love science! I was so impressed with how well you worked together to plan your boats and make changes based on what you observed.

    There was so much amazing learning happening while you were all having so much fun! I loved seeing the excitement on your faces as you tested your boats.

    I can’t wait to show your video to the 2/3′s. They did a challenge similar to this one in the past and I know they will love seeing the boats you made.

    Keep up the fantastic work, scientists!

    Your friend,
    Mrs. W


  12.   Maggie Says:

    Dear Mr.Salsich,

    I had so much fun with the boats! Science is my favorite subject in school because you can still have fun while learning. The first time me and Alexandra’s boat held 78 marbles but the second time we got the boat to hold 145 marbles. I can’t wait to see what you have planned for the next science lesson.

    Maggie :)


  13.   Jack Says:

    Dear Mr. Salsich’s class,

    Building boats with no directions was an excellent idea. We got to build boats, too. But we had to follow the directions. But we got to chose a name for our boats and we got to color them. But it was still a lot of fun. We used building blocks instead of marbles. But we got to use tin foil. Which boat floated the longest and who made it?

    Your friend from Techie Kids,


  14.   Sara Says:

    Dear Mr.Salsich,

    That’s really cool your class got to make boats. My favorite part was when you tested how many marbles fit on the boat until the boat sunk. I have never done a sink or float, but I hope to do one soon. I don’t know how heavy steel ships float, if they think the tinfoil was light and that’s why it floats. Do you Know why? That would be a cool one to find out and test on. Well again that was really cool,

    Your Friend,
    Sara from Techie Kids


  15.   Paris, Molly and Chloe Says:

    Dear Mr Salsich and class,

    I like your experiment, I think it was amazing!

    I enjoy your posts lots.
    What do you like to do after school?
    What is the most popular food for snack and lunch?
    What does your class look like?

    Well I hope you get back to us!

    Bye For Now,
    Paris, Molly and Chloe


  16.   Makayla Says:

    Dear Mr. Salsich Class,

    Last year in third grade we build boats in Science class and it was fun building the boats. Your kids were very good at building boat and were trying your best at building boats. It was kind of hard building boats. Was it hard for you guys?

    Please comment me back if you can.

    your friend, Makayla


  17.   Erik Says:

    Dear Mr.Salsich’s class,

    I think the lightest object is tinfoil because it is flexible and it can change shape when something goes into it. I think the heaviest object is the sponge because it soaks up water. Another heavy object is clay because it is the hardest thing to use and it does not float.

    From your buddy,


  18.   Madeline Says:

    Dear Mr. Salsich’s Class

    I have done a sink-float experiment. I did it in first grade and in third grade, in science class. I think the tinfoil is light too, but it depends how much there is.

    I think scientists learn by taking chances and doing experiments, just like the class is.

    Your Blogging Buddy,
    Madeline from Techie Kids


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