Monday, November 4, 2013

Race a Speedboat


Can you make a paper boat race across the water just by gently touching the surface of the water?
Gently does it...

Hypothesis (What I think will happen)

Crighton: "The washing liquid will make bubbles and push the boat along the water."
Hemani: "I think that as you touch the water gently with a little dish wash on your finger the water might get a little bubbly and it might make the water push away. Just like how I wash the dishes at home. As I put the dish wash on any plate or glass the soap starts getting bubbly."
Marcus: "I think that the dishwashing liquid would make bubbles and when the bubbles pop it would let out air and then the air will push the boat."
Bree: "I think the dish washing liquid will make bubbles and the the bubble will make wave and the boat will move."


Coloured card, washing up liquid, pencil or sharpie, scissors, large container of water.

Method (What we did)

  1. Drew and cut a boat shape (bird's eye view) out of the cardboard.
  2. Teva: "We gently put our boats on the water, and tapped the water with washing liquid on our finger." 

Observation (What happened)

Elijah: "When we put our fingers in the water, the boats moved." 
When I did it with Room 18, the boats moved across to the other side.

Speedboat from Kieren Moriarty on Vimeo.

Conclusion (Why I think it happened)

The water surface tension is broken behind the boat. This means the surface tension is stronger in front of the boat and it pulls the boat forwards.

Short Experiment to Follow Up: Make Metal Float

Gently place a paperclip on the water’s surface.
Heavy metal?

What will happen? Will it sink or float?


  1. Hi Room 16,
    I have really enjoyed reading about your science experiment. You obviously all thought carefully about your hypothesis before you started your investigation. Did you try the same experiment with any other substances on your finger or with a clean finger? I wonder if you would get the same results?
    The class I work with are new to blogging so we haven't put any of our science investigations on to our blog yet. It was great to be able to read yours.
    Kind regards,
    Miss Williams
    Teaching Assistant

    1. Thank you for your comment, Miss Williams.

      We did not try the experiment with other substances. However, we did find that when one group broke the water surface with their hands prior to the experiment, that it didn't work. So, a different result.

    2. It looks like a really good enjoyable experiment!

  2. Wow Mr Moriarty!
    I really love how you have created a video asking a question in the start.
    I also like how you have put peoples predictions in too.
    The caption for the last photo is a great caption.
    Well done Mr M:)

  3. Awesome Mr M!
    I like the short 12 seconds video,
    I like the Crighton's and the other kids hypothesis.
    Keep up the great posts! :)

  4. Awesome post Mr M.
    I really like the science video.
    Its a great experiment.
    Well done.

  5. Awesome post Mr.M,
    Science has been so fun lately.
    Great video!
    I really liked that experiment.
    Well done:-)