THINGS THAT FLOAT
Ralph the Rugged Raft
Cartesian Diver Construction Process
My Video Showing off my Diver!
Why it Works
Materials Used
Figuring out the volume of Jeff's head!
My Density Demonstration
Materials: ​​
PART 1
PART 2
As I pore the oil into the water, the oil doesn't mix or dissolve into the water, but rather settles at the top of the water, making a thick layer of oil. This happens becuase the oil is less dense than the water, meaning it is lighter in comparison to waters mass and volume. Next, salt sinks to the bottom when added because it is heavier than both oil and water. The salt carries some oil with it as it sinks to the bottom, as you can see by the blobs traveling downwards. Next, as the salt begins to dissolve into the water, the oil that was once trapped with the salt, is released and floats back to the top. The food coloring allows one to see the oil as it travels back up in the form of blob bubbles shown in the video.
What is Happening?
Procedure:
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Fill your clear glass about 2/3 of the way with water
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Pour vegetable oil into your cup. (You want to create a layer that’s about 3/4-1 inch high.)
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Add one drop of food coloring to the cup.
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Sprinkle salt into your cup and watch what happens!
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Continue adding more salt and observe.
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Clear glass
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water
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vegetable oil
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food coloring
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salt
For this project, we made a Cartesian Diver that consists of a 2L bottle, water, a nut, and a pipette. Our task this week is to trick a friend on how the pipette is able to float up and down inside the bottle, before explaining how it works.
This week we learned about density! We practiced exploring density by creating our own boats and teaching a friend about our cartesian diver.
Density: how much stuff (mass) in how much space (volume).
Here is a great video that explains density:
The goal of this activity was to take a chunk of clay and make a boat that was able to hold 30 or more pennies.
Our Results:
My partner and I made a boat that held 21 pennies at the most!
*As a class, we found the shape that worked the best was a circle shape. The circle also needed to have a rounded bottom, lots of space in the middle, and high edges.
*We also found the shapes that tended to sink were solid shapes, a solid bar, and pancake shapes.
We created Ralph with a flat, round bottom that was very wide in order to have a bigger surface area. We also added in high sides to keep the water from getting in the heavier it got! All of this made our boat low in density, making it float!
THE BIG IDEA: "Things that are more packed together tend to sink. Things that are less packed tend to float."
MATERIALS USED:
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A block of clay
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pennies
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tank
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water
Less packed things
are less dense
ON AVERAGE
More packed things
ON AVERAGE
are more dense
Cartesian Diver
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Inside the pipette is a little air bubble at the top
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So, when the bottle is just sitting, the density of the diver is lower than the water, causing it to float.
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But, when the bottle is squeezed, the pressure inside the bottle is increased because the water has less space to move around. So, by squeezing the bottle, the pressure on the air bubble is increasing as water moves into the pipette. As this water is moving in, it is pushing air out of the bubble, making the air bubble smaller. This causes the weight of the diver to increase as water is taking the place of air, making the diver denser and able to sink to the bottom.
Here is a great video explaining how to make a diver and why it works!
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Put a ballast nut at the end of your pipette. Make sure it is on tight as far up the pipette it can go. Then cut the excess pipette end, but not too close to the nut, giving a little room to hold the nut on the end of the pipette.
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Squeeze out the air in the pipette and place it in a tank of water. Fill up the pipette until the very top is barely floating. You can measure this by placing your pipette into your water tank.
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Fill a 2L soda bottle and fill it with water all the way to the top, almost so it is overflowing. Next, you are going to place the pipette inside the bottle and twist the cap on. Fill the pipette with more water if needed.
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Once the bottle is closed tightly, squeeze the bottle to make sure the dropper moves down to the bottom. If this does not happen, take out the pipette and slowly add more water to it. This step is tedious and takes time!
Another Density Demonstration
This bottle contains salt water, 2 types of beads, and rubbing alcohol.
HERE IS THE LINK TO THE BOTTLE DEMO & KIT: https://www.teachersource.com/product/poly-density-kit/density
The air is the least dense, staying at the top, either way, you flip the bottle. The alcohol is the next least dense, followed by the white beads, blue beads, and finally, the salt water at the bottom.
Next, shake the bottle so all the components are scrambled up!
Watch as the alcohol and salt water mix, leaving air the least dense at the top, followed by the white beads, the mixed solution, and then the blue beads. *As the solution mixes, the salt components (NaCl) keep the water and alcohol from mixing together permanently. The beads slowly start to come back together in the video.
The saltwater and alcohol unmix and the solution sets back to its original state.
WHY ICE FLOATS
Alcohol is less dense than water so it floats. Ice is denser than alcohol but less dense than water! Water is made up of tiny molecules floating all over the place. As it freezes, the molecules spread apart and form a circle, becoming less dense as they expand.
(People holding hands and stepping apart)