Tag: floating and sinking (Page 2 of 5)

Weekend Science Fun: Hot and Cold Water

Want to have some more fun in the sink or bathtub? Let’s take a look at how hot and cold water act when they are together. Note:  always watch children around water.

You will need:

  • A plastic test tube with a cork or narrow plastic spice jar (empty) with a cap
  • Food coloring (helps you to see the results)
  • Ice cubes (optional:  colored with food coloring)

Fill a tub or sink with cold water. With an adult’s help, fill the plastic container with hot tap water and then add a drop or two of food coloring. Plug the test tube or cover the jar. Sink the container of hot water to the bottom. Gently open the lid, without disturbing the surrounding water too much. What happens?

Now, do the reverse. Fill the sink with pretty warm water, but not so hot that you will get burned when you put your hand in. Put cold water into the container and add food coloring. Stopper it up and then sink it to the bottom. What do you think will happen when you release the water? Gently release the water. What happens?

If you aren’t going to do the experiment, then you can find out what happens when you put dyed cold water into a bath of warm water by watching this video (cat is optional :-).

Now, take a look at an unusual property of water. What happens when you put cold water in the form of ice into a sink of warm water? Does it float before it melts? Try freezing some ice cubes with food coloring in them to see what happens to the melt water.

When water freezes into ice, the molecules actually push away from each other a bit, making water have the unusual property of being less dense at certain cold temperatures.

Take a look at a frozen lake, puddle or pond. Because the ice freezes at the top rather than the bottom of a body of water, living things can stay underwater even in the winter. Cool!

Bathtub Buoyancy 2: Paper Boat Floating Results

Are you ready for the results of the floating experiment for paper boats? (See “How Long Can a Paper Boat Float?” post)

A friend did this test, although she didn’t say what kind of boats or for how long. Our friend found “the one that lasted the longest was made from a wax paper sandwich bag.” Thanks M!

We folded 5 different boats out of various papers and then floated them in plastic bins filled with water. We left the boats in the bins outside for 24 hours.

paper boats

Here are our results:

1. We made a newspaper boat, inspired by the “Curious George” book. How did it do?

paper boats

The newspaper boat was getting soggy after about ten minutes and went down in half an hour.

2. Paper boat number two was a piece of computer/laser printer paper rescued from the trash.

paper boats

How did it do?

paper boats

It actually sunk right before the newspaper boat, although in the past I have had computer paper boats make it over night. Perhaps it was folded more tightly than this one or the paper was a different brand.

3. Number three was a small piece of bubble gum wrapper.

paper boats

It floated 24 hours. Go, gum wrapper, go.

4. The fourth paper boat was a folded piece of yellow legal paper.

paper boats

It was still going strong after 24 hours, although its bottom was a bit soggy.

5. Paper boat number five was also made of yellow legal paper, but it had a fancy wing design.

paper boats

It was also floating after 24 hours.

We didn’t try any coatings or finishes, which would probably have allowed our boats to float even longer.

Edit: See our final results

If you want to be inspired to make a paper boat, try reading:

Curious George Rides a Bike
by H.A. and Margret Rey
In this book, Curious George makes a paper boat regatta. The instructions for folding the boats are included.

The Complete Adventures of Curious George: 70th Anniversary Edition
by Margret and H. A. Rey

The Amazing Book of Paper Boats: 18 Boats to Fold and Float by Jerry Roberts, Melcher Media, Willy Bullock, Melcher Media

For more advanced boat builders (although you wouldn’t want to float them when you are finished). Assembly trick: investigate some of the tape adhesives used for scrapbooking.

Disclosure: The books above were from our local library. Also, I am an affiliate for Amazon. If you click through the linked titles or ads and make a purchase, I will receive a small commission at no extra charge to you. Proceeds will be used to maintain this self-hosted blog.

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