How To Learn More from Making a Tin-Can Phone

Everybody's made a tin-can phone or string phone as a child. They're fun, they work (Can you hear me? Yes!!!), and they're quick and easy to make. But what can we as parents and teachers do to increase the fun and learning? Read on for the basics of how to make a tin-can phone, and then read some ideas for experimenting for more fun and learning!

photo by Florian Seroussi (CC BY-NC-SA 2.0)

Making a string phone is easy. Here's what you need.

• Two paper cups.
• A length of non-stretchy string.
• Something to poke holes in the cups (a sharp pencil will do).
• Two paper clips (big ones work best).

And here's what you do.

1.  Poke small holes in the bottom of your cups.
2. Poke string through the bottom of each hole.
3. Tie a knot around each paper clip so that the that the paper clips are inside the cups. This anchors the string and prevents it from pulling through the hole in the cup when you pull the string taut.
4. Decorate as desired.
5. Enjoy your phone by holding the string tight between two people. One talks, and the other listens. 

 Then experiment!

 

My students experimenting with string phones

Kids will probably have lots of ideas for experimenting with their string phones, but here are some to get you started.

• Make a phone for each person and connect them so everyone has an earpiece and a mouthpiece as in the photo above (They could hear each other well).
• Try different materials: cans or plastic cups instead of paper cups, different kinds of string or twine.
• Experiment with the string length. How long of a string can you use before the sound is too weak to hear? The video after this list shows people who really push the limits.
• Do the people on the phone need to be in a a straight line? Try talking with the string going around a wall corner. How about around the leg of a chair.
• Will the phone work if the string passes under a rug? What if it's wet? What if someone pinches the string?

Can You Hear Me?: The Longest Tin Can Phone Ever.

 

What do kids learn from string phones?

Kids often understand intuitively why things work if they get hands-on and experiment a lot, but it never hurts to ask the "why" question and see how much they really understand and what needs to be taught. Depending on the interests and abilities of your children, they can learn about sound waves and what media sound travels through, how signal can be dampened and amplified (maybe focused is a better word). They can also learn some engineering when they try to keep the line tense without it ripping through the cup. Kids can learn about real telephones which operate on the same basic concept, except the sound signal is electronic instead of accoustic. (Here's a page about how telephones work.)

Enjoy your string phones, and if you have questions or ideas for further experiments, please leave a comment!

Home-Made Hot Air Balloon

The first human flight took place in a hot air balloon in France over 100 years before Orville Wright took to the air. It's not easy to make a working airplane, but balloon technology is simple--just heat the air inside a balloon so that the air inside and the contraption itself are lighter than the air that is displaced.

We made our balloon with a thin trash bag, straws, aluminum foil, tape, and six birthday candles, following the excellent instructions from sciencetoymaker.com.

Here is our balloon's second attempt at flight, after trimming some weight from the straws, trash bag, and foil.

 

 A fun way to add some literacy and history to this activity for younger kids is with Hot Air, the story of the first balloon flight with passengers aboard (animal passengers). For older kids, The Twenty-One Balloons a fun mix of fiction, history, and balloonology is recommended.

Enjoy making your balloon, and keep a fire extinguisher or bucket of water handy just in case!

 

Be a Citizen Scientist

Citizen science is a fun way to participate in a bigger science project than what one can do at home or even in a lab. Citizen scientists help collect data for professional scientists to analyze--think bird counting or amateur astronomy. Or they can help analyze and report on data that has been gathered by professional researchers.

At zooniverse.org, you can mark and measure craters on images of the moon, help model the Earth's climate 100 years ago by transcribing Royal Navy ships' logs from World War I, or identify species and ground cover on the sea floor. These are just a few of the science projects available to work on and there are over 800,000 people taking part worldwide. My son and I analyzed some photos of animals in the Serengeti that were taken with motion-sensor-equipped cameras.

Scientific American has a list of current citizen science projects.

Scistarter.org is a kid-friendly portal for citizen science. It helps budding scientists find projects based on topics, activities, locations, cost, and more. Some of the projects are gamified to add more elements of fun.

Please let me know in the comments if you've participated in any citizen science projects, or would like to.

How Do Bats Poop?

Have you ever wondered how bats pee and poop while hanging upside down without getting it all over themselves? Me neither. Nevertheless, my son and I discovered the answer today by watching some bats at the zoo. A bat, which had been hanging upside down by its feet, flipped over, hung by its wings, relieved itself, and flipped back upside down. Another one did this shortly after. I never knew that bats' arms/wings were strong enough to hold their body weight, but evidently they are, at least for a short time.

Fruit Bat at Rest (by Ben Charles)

These are the kinds of things you don't read about in textbooks. You just have to be there for the experience. I discussed this in my post a couple weeks ago, "Kick Your Kids Out of the House," and it should be self-evident, but I think it bears repeating that we learn much about the natural world, by being out in it. Science education is more than book learning!

I know I just knocked book learning, but I can't help plugging a wonderful book about a bat that gets adopted by a family of birds. The story is touching, the illustrations are excellent, and the science is good. If you haven't read Stellaluna, by Janell Cannon, please check it out. You can view the first few pages online by clicking the book cover to the left, but unfortunately you can't see the beautiful illustrations, only the text.

Question: What is something you've learned about nature just by being there to experience it?

Make a Homemade Paddleboat

Tokyo had a big typhoon today, so we came home early from school and work. My four-year-old and I watched a TV segment about how to make a paddleboat with recycled materials and just had to try it ourselves. Here's the way to make your own paddleboat if you want to try it at home.

Materials:

• Styrofoam tray

• A pair of chopsticks (pencils or craft sticks would work too)

• A milk carton or something similar

• Electrical tape (Scotch tape doesn't hold up well in water)

• A rubber band

Procedure:

• Tape the chopsticks to the sides of the tray. We found that wrapping the tape all the way around the tray prevented the chopsticks from falling off when the rubber band was wound up.

• Cut a rectangular piece from the milk carton for a paddle. Experiment to find the best size.

• Tape the paddle to the rubber band and stretch the rubber band across the chopsticks.

• Accessorize with Lego if you feel the urge.

• Wind up the rubber band paddle, place your boat in some water, and enjoy! The video below is our paddleboat plying the waters of our bathtub.

You can use this paddleboat project to explore the ideas of potential and kinetic energy, or actions and reactions. Today we just had fun sending our boat back and forth across the bathtub. I'm just going to say that the physics lessons were learned intuitively.

Question: What's a rainy day activity that you enjoy? Please share in the comments.

Kick Your Kids Out of the House

My older son loves to spend summer days in the park near our home, searching the trees for cicadas. When he finds one within reach, he catches it, looks at it for a while, and lets it go. He has been doing this for years, but it wasn't until recently that I realized how much he is learning just by spending time outdoors.

Cicada in Japan (photo by autan)

The other day day he said, "Dad, did you know that cicadas are higher in the trees late in the summer? I don't know if that's because they keep climbing, or because the ones lower in the trees get eaten." That is some deep scientific thinking. He observed a natural phenomenon and hypothesized some possible explanations.

He also noticed that one kind of cicada tends to have more wing damage than another. He reckoned that this could be either because the first kind comes out earlier in the summer and has more time for the wings to get wear and tear, or that it crashes more often due to reckless flying.

He made several other acute observations about the animal and plant life in our neighborhood. When I see other kids lugging their books back and forth to cram school, I feel sad for them. They are missing out on so much life and learning all around them. We need to give our kids more free time in the outdoors.

This free and active exploration is a lot closer to what real scientists do than the experiments that children do in their science classrooms. Too often, those experiments are really just demonstrations, recipes that deliver predictable results if followed precisely.

I'm not the only one advocating more outdoor time for kids. In the second of his pair of articles entitled "Want Your Kids to Get into Harvard? Tell 'em to Go Outside," Richard Louv writes in part:

Children are more likely to invent their own games in green play spaces rather than on flat playgrounds or playing fields. Green play spaces also suit a wider array of students and promote social inclusion, regardless of gender, race, class, or intellectual ability. One study found that so-called at-risk students in week-long outdoor camp settings scored significantly better on science testing than in the typical classroom. At the Human-Environment Research Laboratory at the University of Illinois, researchers have discovered that children as young as 5 show a significant reduction in the symptoms of attention deficit/hyperactivity disorder when they engaged with nature.

So how about it? Ready to kick your kid out of the house for a few hours? If we can do it it Tokyo, you can do it anywhere.

Question: What's a discovery that you or your child has made just by spending time outdoors?

Cloud in a Glass

We found a simple weather experiment online and tried it at home this morning. The idea is to make water condense in a glass to simulate cloud formation. You fill a glass about a quarter full with warm water and place an ice cold metal dish on top. The water vapor in the warm moist air trapped in the glass is supposed to condense as it cools near the cold dish and form a cloud.

Our first attempt didn't work. I think the problem was a combination of the water not being warm enough and a gap where the rim of the glass and the bottom of the bowl met.

First try. No cloud, just some condensation on the bottom of the bowl.

So we tried again. This time we heated the water more and put it in a different cup, one that we hoped wouldn't have a gap. We heated the water too much because the water was steaming even before putting the cold dish on top. The glass immediately fogged up with condensation and we couldn't see whether a cloud was forming inside or not. Steam escaped through the gap again.

Second try. The water was so hot that it immediately fogged up the glass.

So we tried a third time. We let the water cool a little and covered the glass with plastic wrap so no water vapor could escape. We put the ice on the wrap and watched the condensation happen. Again, no visible cloud inside the glass.

Third try. We definitely saw condensation, but no cloud.

 This experiment turned out to be a good one for the kids to learn that whatever the expected outcome, good scientists don't fudge their results. Instead, they learn from what they observe and think about how to structure the experiment better next time. We did observe condensation when hot moist air met cooler air, and the kids could visualize how clouds would form. Here are their write-ups.