intro to hot chocolate
For your lab, you’ll be investigating what’s known as the “hot chocolate effect.” You don’t need to know anything about this effect and you certainly don’t need to try to look it up or read about it. (This usually just makes things worse.) Instead, take a look at my intro and then use this as a starting point for your own investigation:
Truly, I hope you always tap the bottom of your mug from now on when you stir hot chocolate.
(I created this other post for the general public about this effect, too. I think the effect worked better in this video.)
hummingbirds in slow motion
I don’t have much to say about this except I really enjoy watching hummingbirds. Even in slow motion they’re still really fast. I like the way that they turn their wings and use their tails to maneuver, but I’m especially fascinated with how still their heads are while everything else is moving:
getting into the swing of data collection
One of our first tasks has been to collect some data on an object known as a “simple pendulum.” There’s no perfect simple pendulum, but instead this term is used to describe something that swings back and forth with all of its mass stuck to the end that’s swinging. A yo-yo swinging back and forth is a good example, or maybe a tetherball at the end of its cord; but lots of things are really close to a perfect simple pendulum. In fact, I was counting on the fact that you could find something that would work, likely right there in front of you.
Here are the instructions I gave for setting this up:
Then, you each collected data from your own objects: keys at the end of a lanyard, the adapter at the end of an electrical cord, a weight at tied to the end of a string, etc. These all work — though you might wonder if it’s okay to all be using different things if we’re going to share the data with one another. That’s a good question, and we’ll get to this.
After everyone reported data for the length of their pendulum and the time it took to swing 10 times, I took all of that and made a graph. Here’s an example:
I love this graph for a few reasons. First and foremost, you each collected ONE piece of data, and that single piece of information didn’t tell you very much. But now we have it in the context of all the other data. You can see how yours compared to others. More important, you can see if there are any patterns in these data. To me, it looks like there are. I tried to sketch some of what I’m seeing right on the graph:
MOST of the data show that the shorter strings take the least amount of time to swing, and the longest strings take the greatest amount of time. In addition, it looks like those times change most drastically when we change the shortest strings, and they change less for the longer strings. This makes a kind of curve that seems to be getting flatter and flatter as you go from left to right (shorter to longer strings). There’s a pattern here, and your data likely fits right into it. But we needed lots of these experiments in order to see the bigger picture. In fact, now we can even imagine that this curve could be described mathematically. Nature actually abides by this mathematical relationship — or maybe it even invents the mathematical relationship for which we needed to invent the mathematics!
For now, I’ll leave you with a few questions:
- Seeing that there’s a pattern here, what do you think a shorter pendulum would do? A longer pendulum? In other words, does this graph/pattern tell us about other pendulums we didn’t collect data for?
- I never told you to use a specific kind of object, so people probably used objects that had different masses (or weights). They probably also had bigger and smaller swings. Since we didn’t account for those variations, what might that mean?
- Not everything fits the pattern perfectly, and there are definitely a few outliers. Why? What do you think happened? What does this tell us about collecting data, conducting experiments, and creating investigations? Or, maybe more broadly, what does this tell us about science? Can we trust it?
bees in slow motion
I put a camera at the entrance to a bee hive and took slow motion video of these honeybees. Each time I watch the video I see something different and am fascinated by the way that bees fly and control their path. I also just like their behaviors as well as some interesting play with the light. Oh, and you should be prepared to observe how the slow motion also affects the sound.
There’s a good bee blooper at the very end, too.
And here’s another longer video I took later from above the hive:
What do you observe about the bees and their behaviors outside of the hive? What about the way they fly and maneuver? How do they take off and land? What do you imagine they’re all doing? What else do you notice? What do you wonder? How could you study this, either with the video here or in another way?
Epilogue
It’s probably worth noting that I can politely hang out right next to all of these bees. They’re very busy and don’t want to bother me as long as I don’t bother them. In fact, my son, Reed, is so good at calming a bee that he can coax it onto his finger — something he did once when Victoria (the bee) was inadvertently stuck in the house and being chased by Gus (Reed’s cat). Honeybees are not only easy to live with, they’re important to our way of life. You might take a look at some things you could do to help honeybees.
I also have a few other resources:
- This collection of slides I used for a presentation on honeybees.
- A photo album of some of my photos of bees I’ve worked with.
balancing acts
If you see me in front of an in-person class and I have a meter-stick, you’ll often witness me trying to balance it in various ways. The most impressive and kind of magical way to balance a ruler, stick, baseball bat, etc., is using this trick of sliding your fingers towards one another. They naturally meet up at the exact balance point, even when the object is lopsided. Take a look:
I also like this video because it shows me messing up and dropping stuff, and there’s a great cameo of our puppy, Nina. Oh, and the intro and outro features my favorite band.
What other objects can you balance? Can you create an investigation around finding the balance point of an object under different conditions? How would that point shift if I kept adding weights to one end or another, or to a different spot? What other strangely shaped objects would balance this way?
raisins in soda
For some people in my family, there’s no good use for a raisin. I happen to disagree. I love them mixed in with nuts and candies, and I also discovered that they make for a great science investigation. When someone set aside all of their raisins, I decided to take video of what happens when I put them in soda water:
When you watch this, you probably have some observations, ideas, and questions. What makes the raisins go up and down? Why are some stuck on the bottom? Why doesn’t my family like raisins? For me, the more closely I look, the more questions I have and the more different things I’d like to try out.
While you’re thinking about this, here’s another video of the same raisins. This one is up close, and most of this video is shown in slow motion so that you can look really closely at some things going on.
You might want to look at this a few times closely, but maybe this is just the first step. If someone in your family doesn’t like raisins and shares them with you, maybe you’ll put them in a favorite drink and see what happens. There could be other liquids and other objects that could do similar things.
ice melting
On hot summer days you might really enjoy a glass with ice, just because you like a cold drink. But have you watched the ice in your glass up close?
I like investigations just watching ice melt. By taking some video and speeding it up, you get to see the whole process in just a few seconds. Here’s an example where we take ice that’s made from water with red dye. This way, as the ice melts you get to trace where that new liquid goes.
When you watch the ice melt, it’s funny that it goes from the top of the glass and falls to the bottom. What makes it do this? Why did it float in the first place? What would make it sink?
There are other liquids besides water that we can’t drink, but we can still put ice in them (as long as we’re very careful and label these liquids so we don’t accidentally put them in our mouths). I decided to compare what regular (water) ice does when it melts in water compared to when it melts in rubbing alcohol (isopropyl alcohol) that you can get at a pharmacy or grocery store.
Here’s a fast timelapse of these two, side-by-side. We think there’s a lot of interesting things going on, even at the beginning before any melting has happened. We added some salt at the bottom of the isopropyl alcohol to make it a little easier to see and to make some salt water as the ice melted.
I really enjoy making these videos because then we can replay these episodes really quickly and make comparisons. But it’s also great just to see how ice melts in different ways in real time. You could make videos; or, you could write notes or take pictures or just observe and talk to others about what you’re seeing. You might think of other variations on this theme.
sun circles
It was a nice morning, and I thought it would be a good choice for me to sit in my backyard and read a book. But it’s easy for me to get distracted, and soon I was really interested in a spot of light that was on my chair:
(For more information about this great book, see:
https://www.hepg.org/hep-home/books/science-in-the-city)
I wondered what made this spot and I turned around to see how sunlight was coming through this tree behind me:
What I think is really amazing is how all of these leaves and the gaps between them are different shapes, but the light coming through makes circles. I used a white notecard to find more of them:
You’ve probably seen spots like this before, maybe without even knowing it. (Once you start to see them in a few places, you might have a hard time not seeing them!) Sometimes under a tree we say that there’s “dappled light,” but it doesn’t matter what you call it. There are funny shapes and a kind of light that photographers and artists like, all made by the overlapping circles of light like this.
Can you find circles of light like this in other places? What do you think makes these circles? Why are there so many? Are there other ways to make these sunshine spots? Could these circles be a picture of something else?
waves on a lake
On a camping trip a while ago, we had a site that overlooked a small, calm lake in the Uintas. From a perch we could toss small rocks into the lake and watch the ripples they created. Tossing two rocks at the same time made it so that we could see what happens when the two sets of waves overlap.
You might want to look at the video up close, or even pause it at certain spots to see what’s happening. What do you observe? What patterns do you notice? Where else could this happen?
light in gelatin
Some science investigations are especially fun to do at home. Playing with light and playing with jello are each great activities for indoors. This investigation prompt puts these two things together.
Here’s a video that I made at home, with no fancy lab or equipment — the perfect setting for most science-in-the-making. This is just to give you some ideas of where you can start, but there’s lots more you can play with and do.
In summary, all you need to do is make a gelatin dessert in your choice of flavor/color. Plain gelatin works great, too, but it doesn’t smell as good. When we make it, we just use half as much water (or don’t add any chilled water) and let the gelatin set in the refrigerator overnight. Then, cut out any shapes you’d like and put them on a surface like wax paper, a cutting board, or even just a clean table. Use a small flashlight or laser pointer to shine through the jello from the side, and observe what the light looks like as it goes into, through, and out of the jello. In my investigation in the video, I discovered some new things about how the light gets bent and focused; and I learned that my yellow jello lets through certain colors of light, but not others. I thought this was all really surprising and interesting, especially knowing that it was all caused by my 99 cent box of generic, lemon dessert.
Many other people do jello optics as well. Our friends at the Exploratorium in San Francisco showcase jello optics as one of their “science snacks.” Once you get started you’ll probably find other experiments to create on your own; or if you’re in a course I’m teaching you may be crafting lenses or other light bending and bouncing shapes with jello at home or in the lab.