1. Ice Spikes

Have you ever seen bumps or spikes come up from the ice cubes in your ice cube tray? SnowCrystals.com has a great discussion of ice spikes, how they form and how to grow some of your own. For more pictures and a movie, try Spikes on Ice Cubes.

2. Ice cube rescues

Give your child(ren) a challenge to “rescue” ice cubes floating in a glass of water with only a piece of string and some salt. Then watch this video to see how it is done.

3. Freezing and thawing water

Freeze water in various-sized containers and then set the ice “sculptures” out to thaw. (Set them in in deep bowl indoors or outside on a sidewalk or patio where a little melt water won’t matter.) Time how long it takes various sizes and shapes to melt with a watch or clock. Does size or shape influence melting time? How?

Try freezing a water-filled water balloon (set in a bowl first). Once it is frozen, what happens when you toss it? What happens when you freeze a balloon filled with air in a bowl of water?

4. Floating and sinking

Create an ice cube boat and float it to emphasize that ice is less dense than water.

Gather:

• ice cube tray
• cold water
• pie plate or shallow bowl
• plastic wrap
• toothpicks
• triangle of paper
• clay (optional)

Fill the ice cube tray with water. Cover the tray with a tight layer of plastic wrap, which will hold up the toothpicks. Stick a toothpick in the center of each cube, enough so that there is a least one for each child. When the ice cubes are frozen, remove from the tray. Insert a small triangle of colored paper on each toothpick to make a sail, and float the ice cubes in a bowl of cold water (the colder the better). Do the boats float? Do they stay upright? If not, try adding some clay to the bottom until the ice cubes are balanced. (This may be difficult at first, if the oily clay doesn’t stick to the wet ice. I found it did work with patience.)

5. Moving on to dry ice

Dry ice (frozen carbon dioxide) is available at many grocery stores. Just remember that it is much colder than regular ice and will require special handling. Always use gloves, and tongs are a good idea too. Never put dry ice in a swimming pool!

See this Steve Spangler video for some ideas and handling suggestions.

Ice is so much fun to experiment with in the summer. Let me know if you have any other experiments to do with ice or activity tips.

For more information, try these books:

and these related subjects:

Ice Scientist: Careers in the Frozen Antarctic (Wild Science Careers) by Sara L. Latta

Pioneering Frozen Worlds by Sandra Markle

Note: Be prepared for a mess (we did these outside). We supplied goggles, which we had purchased at a home supply store.

1. Density

Gather:

• periodical table of the elements
• accurate kitchen scale
• two or more objects of the same size made of different metals, for example the zinc and copper plates from a lemon battery kit

Ask the children if they predict the two objects will weigh the same (because they are the same size). If not, can they use the periodical table to figure out which will weigh more? Use the kitchen scale to test their prediction.

The Intermediate Physical Science Kit from Exploration Education has the materials for this activity, including supplies to make your own working balance.

2. A Density Column

A density column is made of liquids of different densities layered one over another.

Gather

• clear container (I used a water pitcher) big enough to accommodate the ladle)
• corn syrup
• water
• food coloring
• cooking oil ( I used canola)
• isopropy alcohol (standard rubbing alcohol)
• soup ladle
• items to test, such as crayons, pennies, hard candies, toothpicks

Ask the children to predict which liquid is the most dense and which is the least. Pour about an inch of corn syrup in the bottom of the container. Add a few drops of food coloring to the water. Hold the ladle with the bottom resting at the top of the corn syrup layer and slowly pour in an inch or so of water. Gently empty the ladle move it up and pour in the cooking oil. Again empty the ladle, move it to the top of the cooking oil layer and gently add a layer of rubbing alcohol. You may also want to add food coloring to the alcohol layer.

Once you have a column, then test how other materials float in the layers. The pennies should be the densest and fall to the bottom. We dropped in Mentos candies, which are made of sugar and glucose syrup, and found they were roughly the same density as corn syrup. The crayons are made of wax, and floated in the oil layer. Our toothpicks were the lightest of all and floated on the alcohol.

We designed our density column based on a video at the Happy Scientist website.
We also found examples at Steve Spangler Science:
Bubbling Density Concoction
and
Seven Layer Density Column

Science is Fun in the Lab of Shakhashiri has a Layered Liquids demonstration as well.

3. Elephant’s toothpaste – recommended for outdoors where messy soapsuds won’t be a problem.

Gather:

• empty plastic water bottles – enough for each child
• hydrogen peroxide (the kind you get at the grocery store works fine)
• baking yeast
• water (food coloring optional)
• dish detergent (we used Dawn)
• funnel
• 1/2 cup measuring cup

Using a funnel, add 1/2 cup of peroxide and a ’squirt’ of dish detergent to each water bottle. In another container, mix roughly two teaspoons of yeast with about 1/4 cup water for every two bottles hydrogen peroxide (doesn’t need to be perfect). If you have a lot of children, you may need two or three containers of yeast/water. Shake or stir the yeast/water, and then pour a couple of tablespoons into each bottle containing the hydrogen peroxide/dish detergent mix. The concoction should erupt in a foamy volcano. Note: this is an exothermic reaction, which means the reaction gives off heat. Allow the children to explore the foam and some may notice the warmth.

The yeast in this reaction supplies the enzyme catalase. Oxygen is rapidly released causing the foamy bubbles in the soap.

For a much more detailed recipe, see Steve Spangler Elephant’s Toothpaste

4. Acids and Bases

Is it an acid or a base?

Liquids tested:

• lemon juice
• dish detergent
• ammonia
• vinegar

The first day we used the standard red cabbage indicator (red cabbage leaves ground in a blender with a bit of water) but the smell was unpleasant.

The next day we used frozen mixed berries ground in the blender with a bit of water. The mixed berries smelled better, although they didn’t give quite as good a range of colors.

Previous post about color and acids and bases

Steve Spangler’s Red Cabbage Experiment

Science is Fun in the Lab of Shakhashiri has an Exploring Acids and Bases Demonstration

If you children are tired of the standard red cabbage indicator, try mixing a little tumeric (spice used in curries) and rubbing alcohol in a small container and then dip in strips of paper towel. Watch out, tumeric will stain like crazy! Allow the paper towel strips to dry on a newspaper.

The tumeric solution makes a lovely yellow color. Once the strips are dry, test your acids and bases again.

We found the acids did not change the color of the strips, but bases made them turn a startling red.

We also used the tumeric/alcohol to write messages on orangy-yellow paper and after they were dry, revealed the “secret message” by lightly spraying with a household cleaning product that contained ammonia.

5. Using chemicals to make light

See Glowing Chemistry for more information

Extensions:

For the person interested in kitchen chemistry, try

Kitchen Science Activities

and Food Science 101 (the chemistry behind a simple cake)

For those interested in learning the names of the elements and their symbols:

Chemical Elements: Origins of Names Trivia Quiz

Free Rice has a chemical symbols challenge

Chemistry is great fun. Hope this inspires you to do some hands-on chemistry, too.

Tracking Trash: Flotsam, Jetsam, and the Science of Ocean Motion (Scientists in the Field Series) by Loree Griffin Burns is about Dr. Curt Ebbesmeyer, an oceanographer who studies the huge streams of water flowing through the ocean, called currents. In 1990 his mother pointed out an article in the newspaper about piles of sneakers washing up on the shores near Seattle, Washington. Dr. Ebbesmeyer turned his scientific curiosity to the problem, and discovered the shoes came from containers that had fallen off a ship during a storm months before. The sneakers floated in the ocean currents and ended up washing up on shore. By tracking how fast and how far the sneakers moved, he and other scientists could map the direction and speed of the ocean currents carrying the sneakers.

Activities:

(Note: always watch children around water).

1. Bathtub or pool currents

Try to create a current in a bathtub or pool using a hose or a handheld shower head. Partially fill the pool or tub with water, then create a fast current by shooting water through it. Try adding a plastic floating toy to track the movement of the water flow.

2. Floating high versus low

Dr. Ebbesmeyer also studied the movement of some floating bathtub toys that had fallen off another boat. He found that the bathtub toys moved to shore more quickly than the movement of currents would have predicted. Then he floated a sneaker and a bathtub toy in seawater. What he saw suggested the answer.

Do you have an old sneaker or similar object that you could use to test this question? Float an old sneaker and a plastic bathtub toy in a tub or pool. Do they look the same in the water? Do they move through the water the same when pushed by currents?

Dr. Ebbesmeyer used seawater for his experiment. How do you think that might change the results?

His idea was that the bathtub toys floated high up out of the water and thus caught the winds. When the wind helps move an object along, it is called the object’s “windage.”

It turns out the plastic tub toys had been packaged in sets of four, yet none of the packages were washed up on shore. He wondered how the packages might influence the movement of the toys, so he placed packages of toys in tubs filled with seawater. He found the packages fell apart overnight, and so the toys were moving freely very quickly.

What else might change how an object moves in the water?

3. Plastic brick floating

In February of 1997 a ship lost containers filled with over four million LEGO pieces into the Atlantic Ocean.

Gather:

• Plastic bricks
• container for holding water, sink or bathtub

Now you are ready to answer some questions.

Do plastic bricks float?
Can you build a boat out of them?
Do you think they would float differently in seawater?

Check out the Techbrick Site for some photos of a LEGO boat race to give you ideas.

Tracking Trash: Flotsam, Jetsam, and the Science of Ocean Motion (Scientists in the Field Series) by Loree Griffin Burns

I admit, I wanted to be an oceanographer when I was in fourth grade. Now through this awesome book I can catch a glimpse of the world of oceanography.

For your information, the last two chapters are more about the trash found in the oceans, the giant pool of trash that is circulating in the Pacific Ocean, and how damaging adrift fishing nets can be. The information would be a tie-in to a study unit on environmental issues, as well.

Boats!

Children are fascinated by boats and floating. You can do a lot of interesting science projects with boats, starting with some basic questions: How can huge pieces of heavy metal float? How are boats propelled? Can you really make a boat out of paper?

We already have covered some floating and boat topics in previous posts.

Why Things Float contains some experiments on floating and sinking.

The How long can a paper boat float? challenge, with the early results for paper boats challenge.
The yellow legal pad boats lasted five days.

The Bathtub Buoyancy Challenge asked kids to find ways to propel boats across a bathtub without using their hands or electrical motors. The Bathtub Buoyancy results show several ways to propel toy boats.

It is always fun to build bathtub-sized boats. This video shows two handmade boats powered by battery packs and small electric motors that my son invented recently. A modified toy car powers the paddle boat; the air boat fan is a modified toy airplane propeller.

Why don’t you try inventing a boat?

For more ideas, try

A Simple Steam Boat at Curious Cat

Miniature Boats at HowStuffWorks

Hope you have fun and let us know what kind of boat you invent!

Edit: To check the rest of the posts on beach science, follow these links:

Sea Horses and Other Fish

Shore Birds

Tide Pool Invertebrates

Beach Science Algae

Beach Science-Sand

Beach Science-Seawater

What do you think? Are you ready to grow a giant pumpkin and give it a try?

Have a fun Friday!

Edit: Check this post for Why Pumpkins Float

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.

Here are our results:

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

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.

How did it do?

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.

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

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

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.

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 by H. A. Rey

The Amazing Book of Paper Boats 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.

Are you ready for another boat building and floating challenge? Let’s see how long you can get a paper boat to float in water before it turns mushy and/or sinks. Although this is called “Bathtub Buoyancy,” I expect you probably would want to carry out the experiment in a bowl of water or other container that could be easily set aside. This might tie up your bathtub for a day or two

Gather:

• Variety of paper products, such as oaktag, printer paper, construction paper, even newsprint
• Test container to hold water, big enough to accommodate your floating boats (Note:  I’m sure you know to always watch small children around water, even little amounts.)
• Optional:  clock, paper and pencil to record results

Instructions: Build some paper boats of different materials, using roughly similar designs. Set them in water and then watch how long they float. You may want to check back every hour or so for boats that are well crafted, others may go down in minutes. Think of ways to make paper boats that float even longer. Yes, you may coat the boats with paint or other waterproof coatings, but not aluminum foil. Then let me know what you find out from your experiments and once again, I’ll post the results in a week or so.

Actually, making a boat out of paper isn’t as crazy as it sounds. For an absolutely fascinating history of paper boats, check out The American Boats... It’s dense reading, but well worth the effort. I’ll talk more about it in the upcoming results post. Hope you have fun.

For a more modern take on paper boats, see this giant paper boat made by an artist at the DailyMail. (You might want to check this website for appropriateness before showing children).

Resource:
Example of Paper Boat Folding Instructions

Edit: For results

1.    Wind or air movement
Probably the most obvious way to propel a boat without touching it is to use air movement or wind. We tried both creating a sail and blowing on it and also using a fan to create air. Both were effective, although somewhat slow and hard to steer.

2.    The classic balloon boat –

You may have seen instructions for these or tried out a kit. I found some available for sale on the Internet (see Resources below) or you can make your own. Check these fun instructions to build a balloon boat from ZOOM, the PBS TV show.

Note:  Please be careful using balloons, and always have adult supervision. Children under 8 years can choke or suffocate on uninflated or broken balloons.

3.    Wind-up propeller
My son took a wind-up propeller from a balsa wood airplane and modified it to propel a flat wooden boat. The stretched rubber band creates the potential energy which is then transferred to kinetic energy. It is fast for short distances.

See the red propeller on the right, rubber band across the center and nail holding it on the left.

4.    Magnet Repulsion
Okay this one was my idea. I remembered moving train cars in a wooden train set by reversing the magnets. It works with an egg carton boat, too. I think this type of boat has the best steering once you get the hang of it.

Here is a short video showing one of our trials. Bear with us, we’re still learning video technology

5.    Detergent Power / Soap propulsion

You may have seen instructions for a soap boat that actually moves. We created one using a top of a Styrofoam egg carton and a squirt of dish detergent. This is not technically a chemical reaction, the movement has to do with the surface tension of the water.

Instructions for a soap-propelled boat from CSIRO.

We simplified the technique a bit by just adding the dish detergent to an egg carton boat and it still seemed to work.

6.    Chemical reactions

My dad told me that as a kid he had a boat that ran on Alka Seltzer tablets. You can also make boats propelled by baking soda and water, or vinegar.

ZOOM has instructions for a Soda Bottle Boat

Good luck and I hope you try some of these. They were fun and we learned a lot too.

Resources for Further Explorations:

Balloon Powered Wooden Boat

Rubber Band Paddle Boat

Let’s Try It Out in the Water : Hands-On Early-Learning Science Activities (Paperback)
by Seymour Simon, Nicole Fauteux , Doug Cushman (Illustrator)

Teaching Chemistry with TOYS (Paperback) by Jerry Sarquis, Mickey Sarquis , and John Williams

Science in Seconds with Toys: Over 100 Experiments You Can Do in Ten Minutes or Less by Jean Potter

Magnetic Boats in the Tub

The challenge is to build a “boat” that will travel on its own, via some propulsion method, from end to end in a bathtub filled with water without being touched by human hands. Measure the length of the tub and record how long it takes in seconds. Electrical motors and/or batteries are not allowed for this challenge, as water and electricity are a dangerous mix.

We came up with four different methods that worked. Let us know what you come up with and what was your best time. We’ll share results next week.

For instructions on how to make some simple boats, see the bottom of the pumpkin floating post.

Edit: Results of challenge 1