Boats

I am going to work with some kindergarten kids on “sink & float” because they are doing some content that is about boat voyages. We will give them a variety of items to conjecture then test whether they sink or float. We will try making a foil “boat” to hold some pennies and see how many pennies they can hold. THEN we will try to make an origami boat…I have not figured out the best origami for that yet (I have done almost no origami, so a new learning experience).

I thought to make some “boats” with digital tools as examples and maybe we will test how many pennies they hold. They are actually just small boxes without tops to keep the shapes simple. I designed a 60 mm x 35 mm x 16 mm boat in tinkercad (I forget why I did 16 vs 15???) A rectangular prism with a rectangular prism hole cut out. Remember, in order to have 3 mm thick sides, the hole has to be 6 mm smaller (3 for each side). I raised the hole up 3 mm to get the bottom of the hull.

I also designed the same shape in makercase to laser cut.

I cut some out of cardboard, wood, and 2 different acrylics using the same file.
The kerf adjustment (accounting for thickness of laser beam on the cut) had different effect because all of them are slightly different in thickness. The wood and 1 acrylic had to be tapped together using a hammer. The other acrylic falls apart, then I realized they are 2 different manufacturers. Obviously I have to get better at kerf adjustment, and it should be done with one material in mind. I think I will “paint” the wood one with water resistant wood glue to seal up some gaps in edges and help it to not absorb water. The acrylics I am thinking super glue.

The 3D printed ones took an hour
The cardboard lasered in 1 minute
The wood and acrylics took 1:40 – 1:50 (minutes)

I also did a cylinder to hold the same volume to see if kids predict fewer or more pennies…but then decided to mix the media and shorten build time. I 3D printed the sides but laser cut the bottom. That is a 20 minute print and 30 second laser cut. I used cuttle for the circle svg. When the 50 mm circle gets laser cut, it is about 49.7 mm (i was wondering if the GlowForge laser cut outside, on , or inside the line – some laser cutters you can tell it where to cut).
 

I will try super glue to connect them.

I did make a mistake with these. I was originally going to make the circle bottom be inside the 3D printed ring…but I changed up to have the ring attach on top of the circle base…which makes my ring 3 mm taller than the other objects, so NOT the same volume.