Age: 7 & 10
Science Co-op Session 1 Week 3: Solids and Liquids are Dense
Agenda:
- 盤古 Pangu – Chinese Creation Myth
- Solids are Dense Lab #1
- Liquids are DenseToo worksheet
- Lab from Daily Living Science 生活裡的科學
Density is a concept that is repeated very often in the First Great Lesson. It wasn’t until training that I realized density had a big hand in how the Earth was formed (air in our atmosphere vs the heavy earth core). It’s why I continue to come back to Montessori science even though I find it hard to implement, because it ties all the disparate scientific concepts together and show how they’re related to each other.
盤古 Pangu – Chinese Creation Myth
For our survey of creation myths, this week I read the children a story out of Hansheng’s Chinese Folklores book 漢聲中國童話故事. Though long, the lovely illustrations always keep the kids engaged. You can click on link of picture to read the text.
Tip: Before starting a lesson, it is good to ask the children if they remembered what they learned last week. “Do you remember the story I read you last week? (Wait for kids to answer) ….Today, we’re going to read another creation myth from a different country….”
Solids are Dense
Materials Needed: plastic bin + tons of stuffed animals
The next activity came from the Real Science Odessy book. I had 5 huge stuffed animals and asked each child to put one into the box. After about two they had to really work at it and we had to close the lid immediately or else it wouldn’t fit.
As I’m looking back on this, I know now I should have slowed down and really ask questions slower and wait for them to come up with the answers; namely, to observe that density is when the particles are squished very close together.
After this activity, we did another one from the book, where the children were asked to go, one by one, into a small hallway closet. They had tons of fun and that made an even more impression on them on the concept of density.
Liquids are Dense Too worksheet
Materials Needed: water, oil, corn syrup, test tube
To prep the kids for the actual experiment, I started by reviewing the concept of solids, liquid, gas for the kids who didn’t have this presentation in our science co-op two years ago. Thankfully, Real Science Odessy (RSO) has a worksheet on it. It asks the children to make a hypothesis, then draw what they observe. Since half the class already knew the answer it was easy peasy. But the kids were quite excited about mixing things in a test tube.
It took a long time for all the kids to fill out their form because most of them are not used to writing.
On a side note, we have a class of kinder to 4th graders. As I told Mandarin Mama the other day, you can tailor the RSO worksheets for children of different levels. Older kids should be reading and writing everything themselves. If they can’t read instructions, read it to them. If they can hold a pencil, ask them to tell you the answer, then you can write it out if it’s a simple answer onto a whiteboard or another sheet of paper, then they copy it onto the worksheet. If they can’t write, then you can prep the answers before hand, show them the answer, they glue it. Or, they can draw the answer if the answer is drawable.
Tons of ways to modify worksheets to a child’s level.
Lab from Daily Living Science 生活裡的科學
Material needed: test tubes, water, alcohol, vegetable oil, dish soap, corn syrup, food coloring, ice cube
Lastly, it was time for the major experiment. I reminded the children what we just did in regards to learning about density of water, oil, and corn syrup. We were now going to do an experiment.
First, the children were separated into two groups. We gave some color to water and alcohol. Each group had to pour the 5 liquids into the test tube and record on paper their density from least to most.
Then, just like the video, they had to choose 3 liquid to use where if you put an ice cube in, it will be at the bottom most liquid layer. (Their answer was dish soap, water, alcohol I think)
After that was done, they then had to choose 3 liquid where if you put an ice cube in it, it will be in the second layer. (I told them between second and third and we ran into issues). In the video, it says between second and third. But it’s really just second. (Their answer was water, oil, alcohol)
A picture is worth a thousand words. Click on them for larger pics
Tips: You can’t add color to oil, it won’t work. When you pick colors, don’t pick dark colors for liquid with similar density. So don’t make water green and alcohol blue. They don’t contrast well. Instead, red and yellow contrast.
Make sure to pour less dense liquid like water and alcohol down the edge of the jar and denser liquids like oil and corn syrup into the middle of the jar. If you don’t, your alcohol and water will just mix together instead of forming layers. We used chopstick to help the liquid pour.
It works better to pour your liquids in in order of most to least dense. Otherwise if liquid has to travel through another layer to sink, it can mix together. All these things can be figured out by the kids. But good for you to know during demonstration.
During lunch time, I showed the kids the video of the experiment. We wanted to see when ice cube was added because we could not get the ice in between first and second layer. This episode in general was a great episode on water and ice. The experiment starts around 20 min in.
The kids ran away by now because they were hungry. So that was kind of it for the day. 不了了之. The parents sat around trying to figure out why it was not going into the right layer.
What I Learned
One major thing I learned is the importance of testing experiment before hand. I tested it at home, and it worked. But because we were in someone else’s house for the presentation, I used other material and did not follow the exact order. This is how we ran into the problem of having different results than what we saw on the video.
I actually had to research why. And I wish that I hadn’t set up too many activities and we started the class on time so the kids weren’t hungry and ran off. Ideally they would be interested in why things didn’t work and want to look up the answer. If we had had time, I would have tried to lead them to ponder this question more.
Because the point of the presentation is to arouse interest and further research more than straight memorizing some fact.
In any case, apparently, ice melts when you put it in water faster than when you put it in oil. So, when we added the ice cube at the end of our experiment, it wasn’t melting fast enough compared with when I added the ice cube first during my trial run. So the ice cube floated to the top of the oil in class and bottom of oil at home.
The other thing is, the density of an ice cube isn’t between oil and water like the Daily Science Video seem to be suggesting (at least that was my interpretation when I watched it). Ice cube has similar density to oil, but as it melts it gets heavier because water is more dense, so it sinks.
Don’t quote me on it.
After this class, I realized the children aren’t quite ready to work in groups, because I didn’t set it up for them to do so. I just kind of lumped them together and expected them to start talking to each other. Especially the younger children, they don’t know how to have a discussion or to problem solve together. They’re quite used to working by themselves. I need to figure out a better set up.
Vocabulary
- Solids – 固體
- Liquid – 液體
- Gas – 氣體
- Density – 密度
Resources
Because I could not procure the items listed in the video, I got ideas for what other things I can put in our 5 layer test tube from these websites: