Whoah! With our covers off, we noticed a LOT of changes. Not only did the weight of the lake drop dramatically, but we noticed this crystal-like substance hanging around the top! Fifth graders also noticed a difference between each of the lakes. Since not every group started with the same volume of water, we're noticing that the lakes with a greater volume of water from the start still appear to be wet, while the lakes with less volume seem to be drier. Hmmmmm....
Students are trying to make sense of what happens to the water droplets they seemingly saw disappear on both the paper towels and the plastic cups. Many students suggested the water evaporated, but what does evaporation really mean? How can we gather evidence to support the claim that the water evaporated?
How long does it take to have water evaporate? Since many bodies of water contain much more than just "water," we've set up three two-bottle systems to see just what happens! One system contains sand/water, another contains salt/water, and the third contains blue food coloring/water. We made observations and predictions today for what will happen to the water over time as the light is turned on...
Wait and see!!!
As fifth graders continue to check in on their lakes, they're starting to make some connections to our driving question, "Why are these ships in a field?" By examining water droplets of even the tiniest sizes, students saw that these drops "disappeared." If these drops of water are disappearing, is it possible that the millions of drops of water in the sea where the ships were located could have disappeared, too? How can we explain this?
Many students suggested that the water on the cups and the paper towels evaporated, but their understanding of how evaporation works is unclear. How do we know that the water wasn't absorbed by the cup or the paper towel on which the water was placed? We'll have to figure out of a way to see if we're right one way or another...
Stay tuned...we'll have to figure out a way to "catch" those tiny water droplets that seem to be floating around in the air.
So we're recording the mass of our lakes daily...
And we've discovered that the lake these ships were in was really a sea, indicating that there was salt in the water. So we're adding salt to our lakes and recording the differences we notice.
What happens to the mass of the salt plus the mass of the water when they're combined? What happens to the volume? What do our results tell us? Continue to check back as we uncover our understanding of mass, volume, and matter!
As scientists, students agreed that in order to see if our lake changes, we'll need to track the changes over time. Besides qualitative observations, students will also be recording the weight of their lakes over time. For starters, we agreed to leave the covers on our lakes to see if there are any changes, and we will soon take off the covers to see what happens. Don't forget--we're trying to explain why these ships ended up in a field. As scientists, we can't visit the actual lake, so building and studying model lakes in our classroom will be a close second!
We also are digging deeper into understanding the difference between weight and volume. We compared two materials in our lakes (water and sand) and discovered that even though we measured the same weight of the materials, they took up quite a different amount of space, indicating that they had different volumes for the same mass. This is introducing the concept of density as "heavy for size." Sand is heavy for size since it occupies less space for the same mass. Therefore, sand is more dense than water, and therefore, it sinks!
With all our lake materials measured (both their weight and their volume), students built their mini-lakes with sand, water, rocks, and gravel. We agreed to measure the weight of the lakes over time, and will keep track of this measurement both in a data table and a graph. Check back frequently to see what happens!
To kick off our next unit, students were asked the Driving Question: "Why are these ships in a field?" Here are some of their responses:
1. A big storm washed them on shore.
2. A drought happened and the boats got stuck there after they sank.
3. Someone brought them on land as a tourist attraction.
4. It's actually someone's home.
5. The water evaporated and the ship got stuck there.
6. A big machine brought it on land.
7. A really high tide brought it on land, and when low tide came, it got stuck.
As we work through these ideas, students will be investigating water transformations to make sense of this phenomenon, of how a ship could possibly be brought on land. To do so, students spent their first day in the unit preparing to build mini-lakes to study, since they can't visit the real lake where this happened (and quite frankly, it would be hard to take a field trip of this magnitude every day)!
Here's all their preparation to build their mini-lakes!