Growing Crystals
The third lesson was a lesson in phases of matter taught by me. The activity was growing crystals and using math skills to measure and count them. The children worked in two groups to begin an experiment. They added baking soda to warm water and mixed it until it was supersaturated. They then decided if they thought the crystals would grow better on a pipe cleaner or a piece of yarn. The yarn and pipe cleaner were each placed on a pencil and placed in separate cups of the mixture. The students also added coloring in order to make the experiment more exciting. Over the next week, the children measured the crystals to see if they grew better on the yarn or pipe cleaner.
Half of the students at my table predicted the pipe cleaner would grow crystals better and half predicted the yarn would grow crystals better (two students picked each out of four total). The students were then asked why they chose that item. None of the students were able to come up with an answer for their hypothesis.
Below is included the lesson plan, recordings of what the children said about the crystals, my reflection, the results of the children's experiment, and some pictures.
Half of the students at my table predicted the pipe cleaner would grow crystals better and half predicted the yarn would grow crystals better (two students picked each out of four total). The students were then asked why they chose that item. None of the students were able to come up with an answer for their hypothesis.
Below is included the lesson plan, recordings of what the children said about the crystals, my reflection, the results of the children's experiment, and some pictures.
Reflection
The children really enjoyed being able to actively add the baking soda, mix it with water, and wait for crystals to grow. One student also had great ideas about what crystals were and how they grow. He said that crystals are like diamonds and that they grow in soil like you would grow plants. The children really enjoyed adding coloring to the mixtures. I thought it was also exciting that I was not sure which one would grow best so I was learning with the students in this experiment.
In the end, it looked as if the yarn grew crystals better than the pipe cleaners. This could be because the pipe cleaners were made of a slippery material and the yarn was rougher and easier for the crystals to attach to.
If I were to do this again, I would probably make it an experiment that I would be present for multiple days in a row instead of once a week, as I cannot be sure if the teacher and students are actually measuring them. I would also like to work with the students two or three at a time. This way I could use more details when explaining what is going on, take more detailed notes of what they are telling me, and guide them more in their measuring. We could also use other materials to make crystals, such as salt or Alum. We could use other materials to grow crystals on including shoe laces, plastic bags, felt, and other objects we find outside or around the classroom. One example I saw in a book also had a string extend between two cups and had the crystals growing in between the two. This would be another option for an extension in the classroom.
I think that the students learned a lot from this lesson. They were able to count the crystals on the pencils. Once the crystals grew to be quite large in number, they needed help pointing to them to keep track of where they were, but they were able to measure them. They enjoyed the lesson and were very excited to talk about it. They also understood the activity and the fact that something had grown. In the discussions, six out of the twelve children mentioned that something had grown and shown up that was not there before. They understood that the crystals grew, changed, and got bigger.
In the end, it looked as if the yarn grew crystals better than the pipe cleaners. This could be because the pipe cleaners were made of a slippery material and the yarn was rougher and easier for the crystals to attach to.
If I were to do this again, I would probably make it an experiment that I would be present for multiple days in a row instead of once a week, as I cannot be sure if the teacher and students are actually measuring them. I would also like to work with the students two or three at a time. This way I could use more details when explaining what is going on, take more detailed notes of what they are telling me, and guide them more in their measuring. We could also use other materials to make crystals, such as salt or Alum. We could use other materials to grow crystals on including shoe laces, plastic bags, felt, and other objects we find outside or around the classroom. One example I saw in a book also had a string extend between two cups and had the crystals growing in between the two. This would be another option for an extension in the classroom.
I think that the students learned a lot from this lesson. They were able to count the crystals on the pencils. Once the crystals grew to be quite large in number, they needed help pointing to them to keep track of where they were, but they were able to measure them. They enjoyed the lesson and were very excited to talk about it. They also understood the activity and the fact that something had grown. In the discussions, six out of the twelve children mentioned that something had grown and shown up that was not there before. They understood that the crystals grew, changed, and got bigger.
The Results
The results of the students' experiment showed that the yarn was a better material for growing crystals than pipe cleaners. The pencils with the yarn grew many crystals where the pipe cleaners grew few crystals or a small, hard blob of crystal.