Whoa, Whoa, Whoa…Volcano!

vinegar, baking soda, and a bottle.
Hard to mess with the classics, but here are some extra tips to try.

A popular experiment with kids is to put baking soda in a bottle and then add vinegar. The mixture foams up and bubbles out of the container like lava coming out of a volcano. We’re no stranger to the volcano experiment, so here are some deeper details you can share with your kids as well as a few twists to try.

NOTE you’ll need to take the proper precautions so that no one gets the mixture in their eyes, mouths, etc.

Vinegar is a liquid that contains acetic acid and water. Depending on the variety, you can find other things in there to give it flavor, like apple cider or balsamic vinegar. The amount of acetic acid varies, but is generally pretty low, so vinegar is fairly weak as acids go. That’s why you can safely use it in cooking. It’s on par with lemon juice (remember that for later).

Vinegar is formed when alcohol is fed to a particular variety of bacteria that converts the alcohol to acetic acid. That’s biochemistry! In fact, it’s the same basic process that’s used in brewing, yogurt making, baking with yeast, and many biotech companies. They all fall under the name “fermentation”. In each case, you have single celled organisms that take a particular food source (alcohol) and convert it to something you want (acetic acid). We’ve done several fermentation projects with our kids, so keep an eye out for those articles coming soon.

The volcano happens when the acetic acid in the vinegar reacts with the baking soda, a.k.a. sodium bicarbonate, a mild alkali salt (it is a mild base, which is the opposite of an acid). This reaction is an easy to demonstrate example of chemistry. When the two chemicals mix, their atoms recombine, creating carbon dioxide, among other things. Carbon dioxide appears as a gas, i.e. the bubbles. They are trapped in the mixture by surface tension, and as more and more carbon dioxide is produced, the bubbles grow and the mixture gets bigger, eventually overflowing the container. ERUPTION! The bubbles in soft drinks are also carbon dioxide gas, but they come from something else. They do behave similarly if you shake up your bottle.

OK, that’s the background. Now the experiments. First, demonstrate the process by spooning some baking soda into a bottle or other container and then adding vinegar. We like to do it over a cookie sheet to contain the mess. Ask your kids to think about what they can change, and then try it out. If they get stuck, here are some suggestions. Be sure to have the kids predict what will happen before you try it. Then afterwards, they can come up with explanations about what they saw.

  • Different shaped containers: bottles (wide at the bottom, narrow at the top), bowls (the opposite), wide or narrow glasses, etc.
  • Different acids: Remember the lemon juice comment? Try lemon juice. Try coffee. Try whatever you have, but don’t waste the good balsamic. Save that for salads. Try buttermilk or kefir.
  • Different base: Baking powder looks and sounds kind of like baking soda. Does it work? What about baking soda toothpaste or kitty litter? What about a fresh box of baking soda vs. an open box that has been sitting in the fridge for months?
  • Different amounts of baking soda and/or vinegar.
soda bread on cooling rack
Mmmmm, homemade soda bread

When you’re done playing around and have washed up, serve up a snack of soda bread. Soda bread is made with baking soda and buttermilk, which is acidic. When the bread is baking, the volcano reaction is going on inside, producing carbon dioxide bubbles inside. That’s what makes the bread fluffy rather than a solid brick. Stay tuned for a soda bread project post.

 

Crittermon GO!

catching a pokemon
Gotta catch ’em all!

If you’re like me, you installed Pokemon GO, um, for the kids to play, yeah, that’s it. It’s a great game for getting out and exploring the neighborhood together. You and your kids probably learned all about what kind of biome is likely to hide a Squirtle and what creature is best suited for fighting a Jigglypuff. If only there was a similar app that would get you and your kids outside learning facts about real plants and animals…

Oh Magikarp, are you in for a treat. Check out the iNaturalist site and accompanying app. It’s a nature cataloging project run out of the California Academy of Sciences. From the site: “iNaturalist is an online social network of people sharing biodiversity information to help each other learn about nature “. They don’t do scientific research themselves, but by creating a huge plant and animal database that includes location and date, scientists can use the data to gain all sorts of knowledge about what lives where, what time of year it’s around, etc. Since non-professional scientists like us are helping out, they call it “Citizen Science” (search that term for lots of projects you can join).

I’m sure the plethora of data the app can generate will be a boon for researchers, but for parents of junior scientists, it offers a great way to get exercise while stimulating curiousity. With my girls, I call it “Real Life Pokemon Go”. Whenever we’re out and about, I have them keep there eyes open for interesting life. Usually they spot bugs and birds, but sometimes we capture flowers that catch their eye. It’s a good tool to get them thinking like a scientist a little bit each day, and it doesn’t drain my phone battery as fast as Pokemon GO.

Sometimes though, you want to go big with a project. For that, we head out to one of the local hiking trails and do a nature scavenger hunt. We form teams with one kid, one parent, and one smart phone with the iNaturalist app per team. Then we set off and try to collect as many different plants and animals as we can by the end of the hike. Hikes often end with lunch or snack at a favorite restaurant, and waiting for food gives us a chance to compare notes.

western fence lizard
My daughter took this photo of a Western Fence Lizard (Sceloporus occidentalis) on a recent hike. Id provided by community members: https://www.inaturalist.org/observations/5729573

A big part of doing science is gathering data. This app lets you become a field scientist as you gather gather gather data. Your kid may wonder what happens with all the data. When you first submit a picture (or three), you have a chance to identify the species. Don’t worry if you don’t know, however, because while there are a lot of folks out gathering data, there are also folks working to identify all of the submitted observations. For you and your kids, that means that usually within a few days, someone will have suggested the proper species name. When you open your app, you can find out what it was you saw. We’ve learned a lot about what lives in our neighborhood that way.

Check it out, and when you submit observations, be sure to add them to the Science With Your Kid project. How many different species can we observe? Check the project link to find out.

Magnify, Now Enhance!

Here’s a little animation my daughter and I made to describe magnifying glasses.

Now here’s an easy experiment you can do with your kids. Hold something about a foot from your eyes. You should be able to easily focus on it. Now bring it slowly closer. At some point, you won’t be able to focus. Light bouncing off the object goes through the lens in your eye and gets projected on the retina (the back of the eye where all the detectors are located). The lens is designed to bring light from far away in focus right on the retina. As you bring something closer to your face, muscles in your eye stretch the lens to keep the object in focus.

diagram of eye
The lens focuses far away objects on your retina.

Depending on your age and how near or far sighted you are, the distance where you can still focus will change. As you age, you lens in your eye becomes less able to change focus easily. If you are near sighted, your eye is stretched out and the lens can’t keep far away things in focus. Normally you wear extra lenses (eyeglasses or contacts) to compensate. If you take off your glasses, you can get something very close to your face and still focus. The opposite is true for far sighted people. They have to hold things farther away to see them in focus.

diagram of eye
When you bring an object close to your eye, the lens can no longer focus its image on your retina and it appears blurry.

If you want to see an object close, you either need to be nearsighted and take off your glasses, or else you need an extra lens between you an the object. A magnifying glass held at just the right spot, can change where the light focuses, allowing you to see close objects clearly.

diagram of an eye
Inserting a magnifying glass between the close object and the eye focuses the object on the retina again letting you see the magnified image clearly.

Paleontology Toys or How To Cover Your House With Plaster Dust

Mega Fossil Mine Dig Kit box cover
Mega Fossil Mine Dig Kit box from amazon.com

For Christmas last year, my then 5 year old wanted all things paleontology. And Lego. We opted for the former since we knew she had lots of Lego sets coming. We got her a great dig-your-own-fossil kit from National Geographic called the “Mega Fossil Mine Dig Kit“.

She’s done similar kits before, and loved them, but this kit really stood out for us for one reason: real fossils. If you aren’t familiar with these kits, they have small fossils embedded in a big plaster brick. It comes with a brush and digging tool and require lots of elbow grease. Similar kits we’ve tried had plastic replicas or plastic bones that can be put together. Those were fun as well, and she always enjoys getting messy, but something about digging actual fossils out of the plaster really excited her.

It took several evenings to dig out all the fossils, and each night, she would wash off her finds and then show them off to everyone. Once she finished, she set up a little museum and walked us around the exhibits. The kit came with a book about fossils, which we read with her, so she was able to tell us all about them.

Set of fossils on a table top
All the fossils we dug out of the kit.

The only downside to the kit is that the plaster is pretty solid, and she would get worn out scraping and brushing. It took a long time until we hit the first fossil, and she almost lost interest. I helped her get going, and once we unearthed our first find, she was hooked. Still, we had to take turns digging. Kids with more arm strength shouldn’t run into that problem. We’ve tried two other kits. One was very brittle and she demolished it readily. The other is even more solid and she eventually gave up on it. We’ll bring it back out this summer and try again. Oh, also, if you aren’t careful, you can get plaster dust everywhere. We set the brick in a cookie sheet to contain it.

By far, her favorite find was the coprolite, a.k.a. dinosaur poo. You can’t imagine the glee in her voice when she showed everyone her poo. We’ll have to turn it into a necklace. Maybe a good gift idea for next year, though she already wants a chewy toy necklace, so maybe that’s not such a good idea. In any case, this dig kit was a huge hit and helped keep her excited about paleontology. It has now surpassed “face painter” as her longest running “what I want to be when I grow up”.

Paper Airplane Your Way To Being A Scientist

A paper airplane resting in flowersOne of the primary ways to turn your kids onto science is to train them to think like a scientist. You want them to try something, then make a little change and then try it again and notice the difference. By the way, the same is true for engineering.

Take paper airplanes for example. You make one, throw it, and see how it flies. Does it go flat and level? Does it turn? Does it rise, then stall, and then nose dive? Now refold it with different sized wings or bend the wingtips up or down. How does it fly now?

Be sure to only change one thing at a time, that way you can build up and understanding about cause and effect. Adding weight to the nose does this. Throwing it hard does that.

Here’s a short video showing a paper airplane design that isn’t too hard to fold, but which flies really well. I also show some of the things you and your kid can change during your tests.

Enjoy!

Q&A Cat Claws and Iron Man

I...AM...IRON MAN
Iron Man as depicted in the video game Marvel Heroes 2016

I recently asked on Facebook and Twitter for everyone, adults and kids, to send me their science questions. My plan is to collect them as they come in and do a post now and then answering the questions. Don’t wait, send in yours!

My first questions come from Dave Y. and his son, Jack. Dave wrote: “What is the purpose of retractable claws (cats) vs permanent claws (canines, bears, etc)?”

At first I thought that there might be a physiological difference, but that they serve a similar purpose, like antlers vs. horns. Perhaps they got to a similar place from different starting points through convergent evolution, but cats, dogs, and bears aren’t that far apart on the evolutionary tree. Also, while I know a ton about cat claws from 20 years of trimming them, I don’t really know much about bear claws (aside from the pastry).

I discovered that bear, cat, and dog claws are all pretty much the same. The main difference is that cat claws are protractile, which means the claws are normally sheathed, but the animal can flex and make them extend (as opposed to normally being out, or always being out). Protractible claws are found on several predatory animals, but mostly cats.

I couldn’t find a clear answer about why cats have protractible claws, but the most likely reason seems to be that it helps them avoid becoming stuck when climbing trees and allows them to let go of their prey once they’ve killed it. When Harry, my orange tabby, got older, he stopped using his scratching post. Without scratching, his claws got long and sharp. He would sometimes get stuck on the carpet or blankets because the claws would stick out beyond the sheath, which supports the idea. Also, it meant that it was time for a claw trimming (which he hated).

Bottom line: if a cat scratches you, just remember, he had to go to extra effort to pull those claws out. If he merely bats you with claws in, he’s probably just playing. Probably.

Jack’s question was: “How does Iron Man’s cannon shoot?” I’m not as up on my Iron Manology as I should be, so I had to look up his cannons. I assume Jack is talking about the blasts Iron Man shoots out of his hands. It turns out they are “repulsor beams” that are powered by the tiny “Arc Reactor” in his chest. In the Marvel universe, repulsor technology was originally designed as a missile propulsion system, and Tony Stark adapted it to work in the Iron Man suit. The repulsors in his boots allow him to fly.

Repulsors aren’t real, but they behave similar to rocket engines. The difference is that rocket engines need to burn fuel to generate thrust while repulsors appear to convert energy from the reactor directly into thrust. In that way, repulsors are similar to ion engines, which generate thrust using electricity to accelerate ions (charged atoms) and shoot them out of the back of the engine. However, current ion engines can’t produce nearly that amount of thrust. In this case we are squarely in the science fiction world, but grounded in reality.

If you want to keep up to date on the shifting boarder between science fiction and reality, keep your eye on the quantum vacuum plasma thruster, a.k.a. “EmDrive” or “microwave thruster”. According to a NASA study,  it can, apparently, generate thrust without any propellant (fuel), which is ideal for a space ship where weight is a big concern. Again though, the thrust they measured was very small compared to the amount needed to let a person in a metal suit fly.

Bottom line: Iron Man has tiny rocket engine-like devices in his boots and gloves. He can turn them on to fly, or shoot short bursts at his enemies. Imagine getting a second’s worth of rocket engine aimed at you. Not a good idea to get on Iron Man’s bad side!

Paleontology Party!

Fossilized mamoths from the La Brea Tar Pits

My child recently had a birthday. She LOVES paleontology, so she wanted a paleontology themed party, and I was in charge of activities. I thought about doing a “dig up your own fossil” project, but she’s done a lot of those, and they can take a while to complete. Not the best idea for a party full of kindergartners either eagerly anticipating cake or recently having ingested cake.

A few days before the party, I still didn’t have any grand ideas. We had some plastic dinosaur fossils as party favors, but I couldn’t think of any game involving them that didn’t also involve destroying our yard. Instead I borrowed my idea from Halloween: build your own monster dinosaur out of Play-Doh! It would be fun, but not strictly paleontologically themed.

Plastic dinosaur fossils

A friend of mine who is in the field once told me that paleontology sits at the intersection of geology and anatomy. So there I was, staring at plastic dinosaur skeletons and a bunch of Play-Doh and mulling over my options when inspiration struck! Why don’t we flesh out our own dinosaurs by smooshing Play-Doh onto the skeletons. Perfect! It would be fun and messy, but not too hard to clean up after. Also, it would give me the chance to talk about how paleontologists have to look at the bones and then try to figure out what the animals looked like on the outside by modeling the fleshy portions.

Fossil T Rex contemplates Play-Doh

We had a wide variety of Doh colors to choose from, and each kid got to pick their favorite dino fossil. Then they went at it. Some tried to make realistic dinos, while others went for goofy (e.g. the Sweatersaurus who had evolved to survive the cold ice age). The party girl had recently been to the La Brea Tar Pits, so she spread out the black Doh and then walked her dinosaur into it so it could get stuck. Another girl didn’t want to get her fossil messy, so she made a flat piece of Doh, then make footprints. That was another teachable moment, since scientists often study fossilized footprints to learn about anatomy (the gait information can help figure out how the bones went together).

Play-Doh Dino Party!

All in all, the kids had a great time and took home their own creations — hypotheses about how the dinosaurs actually looked. If you’re curious, the Play-Doh came off pretty easily, so the whole project is reusable. We’ll definitely be doing it again.

If you want to try it yourself, here’s what we used: