Moving Underwater

Inspired by our time observing Betta, Kindergartners began to discuss how different marine animals move their bodies. We noticed that our warrior fish swims by moving his tail from side to side. The fins positioned on either side of his body seemed to help him balance and steer. For swimming quickly, we saw that these side fins were held flat against his body but when the fish wanted to stop quickly, it extended its side fins out at the same time, using them as a break. We mentioned that most fish have several fins and we talked about how the fins positioned on the top and bottom of its body might prevent the fish from rocking back and forth, side to side.

We learned that some fish have a swim bladder (an air-filled sac inside the fishes body) that enables the fish to rise in the water. As our Betta comes up to the surface, he allows air to enter through his mouth, or from the bloodstream, into his swim bladder. As the bladder fills with air, the fish rises in the water. The fish sinks when he lets the air leave the bladder.

To demonstrate how a swim bladder works to allow a fish to move up and down we used:

A wide-mouth jar
tap water
2 glass marbles
2 round balloons

Using marbles and balloons we made two different sized swim bladders. We filled the jar with tap water and placed 1 marble inside each balloon. In the first balloon we tied a knot as close to the marble as possible. We inflated the second balloon slightly with air and tied the knot as close to the mouth of the balloon as possible. Then I asked students to predict what would happen when we dropped each balloon in the jar of water. Just as some of them had predicted, the inflated balloon floated and the deflated balloon sank to the bottom of the jar. The smaller, or more deflated the swim bladder, the deeper the fish can swim.

Not all marine animals have swim bladders though and we started to think about how and why marine animals might need to move around so much. Students said that fish move "to find food" and "to get away." After watching a few minutes of Oceans, we talked about how different marine species might be uniquely shaped to help their bodies move in very different ways through the water. Students were especially excited to watch the marine iguana move; we enjoyed seeing it make very deep dives and lumber along the rocky beach in the video. We noticed that its long tail and spiky fins seemed to help it to move quickly through the ocean and that its long sharp claws helped it to climb along the rocky shoreline.

Other animals shown in the video, such as the sea urchin, seem to hardly move at all. But when we watched very carefully, we saw that the sea urchin was actually crawling along the ocean floor. Pumping water into and out of its tubed feet, the urchin slowly glides along the sand. With their long spines we all agreed that other animals would be smart to stay away from the sea urchin!

We are looking forward to future investigations and are excited to learn about how other marine creatures move their bodies through the ocean.

Underwater Lab - Brick by Brick

In math class students were given the assignment of constructing a 24x8x10 ft. underwater research station. Using unit blocks, the students modeled a scaled down version that was able to accommodate 4 people and included a kitchen/living room, bedroom, and bathroom. They built a separate wet lab facility outside the main structure for experiments.

The group worked collaboratively, decided on the base design, and then recorded the necessary dimensions for calculating perimeter, area, and volume, for each room in their station. Their work also involved testing different methods of construction. After some trial and error, the students found that the strongest wall construction resulted when they used alternating brick orientations and that the weakest wall resulted when the brick seams were vertically aligned on top of one another other. Similar testing was done to shore up the corners and the students determined the best method for building and uniting strong intersecting walls.

Kindergartners would not be left out, they helped finish off the station by making signs and labels and thoughtfully affixed them around the underwater research vessel so that each room was clearly identified.

One 2nd grader suggested that the station be lit so we decided to include a lesson on electrical circuits. After a demonstration of open and closed circuits, and a discussion about volts and batteries, the students determined that they would be able to install only 3 small light bulbs (each requiring 2.33 volts) using the provided 9 V battery.

After the group worked together to measure out the appropriate wire lengths and determined the best placement for the lights within the station, we decided that another demonstration was in order.

We ventured outside and using relatively easy to find materials we fashioned a homemade light bulb. As electricity began to flow from our "super battery" it heated up our graphite (pencil refill) and it began to glow!

Wet Pet, Your Pet

A gorgeous warrior fish is the newest member to join our classroom. Kindergartners spent some time getting to know him last week. While making observations about his movements and behavior, they happily made suggestions for the name he should be given. Kindergartners noted that our fish is sometimes swimming in one spot near the surface while other times he can be found resting near the bottom in the rocks.

Therefore one suggested, "He should be named Rocky!"

Another Kindergartner felt the name "Rainbow" best suited him,  she said, "The sun shining through makes him change color."

They pointed out that he has two small fins near his gills that always move very quickly but that his tail doesn't move much while he is resting in one spot.

Students made some beautiful Betta fish drawings as they continued to debate names.

Regardless of the final name, they all seem to agree that the best part of taking care of their new classroom pet is when they are able to feed him his daily allotment of 3 freeze-dried bloodworms!