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ETD 24 A. Draw + Explain at the microscopic level: Why slugs are afraid of the ocean?
November 06, 2013 at 9:59am

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Kelli Vetter
November 07, 2013 at 9:17pm

Parent: Kelli taught me why slugs are afraid of salt water. She first drew out a diagram of the slug's membrane and drew what was in the intracellular and extracellular part of the membrane. She explained how the water molecules and salt molecules move through the membrane by drawing out the aqua pores. I learned that water will go to the negative water potential, or water will go from a high concentration to a lower concentration in the membrane through osmosis. This explanation taught me why slugs shrivel up when salt is placed on them. I now have a better understanding on how cells work in various situations in life.

Student: I talked to my mom about why slugs shrivel up in salt because my mom used to do this to some of the slugs in front of our house. I thought it would be difficult to explain this process without any visuals, so I drew a visual similar to the one we drew in class. I simplified this visual so my mom could easily understand. I talked about the intracellular (inside) and extracellular (outside) part of the membrane to lay a basis of facts about membranes. I then taught my mom how the pores worked, and how different types of transports work within different cells.  I talked about how water usually wants to move from a high concentration to a lower concentration through a permeable membrane. I then talked about the water potential, and how it worked within a membrane. Overall, this helped me understand this concept better because I was able to explain it to my mom in a way she could understand it without missing key points in the concept.

Cooper Larson
November 10, 2013 at 2:18pm

I taught my mom that since the concentration of water in the intra membrane is greater than that of the salt water in comparison to the solute, the hypotonic cell will diffuse water out of the selectively permeable membrane in order to create a dynamic equilibrium between the extra membrane and the intra membrane, causing the slug to shrivel up with the loss of water.

Karina Larson
November 10, 2013 at 2:19pm

From what Cooper told me about the salt in the oceans being lethal to slugs because their cells are trying to create an equilibrium between salt and water, I decided that the next time I find slugs in my garden they will get to swimming in a bucket of salt water.  

Brenda Sifferman
November 11, 2013 at 7:15pm

Peyton taught me about salt, slugs and water.  He explained that the inside of a slug is less salty than the ocean, the water leaves the slug in an attempt to balance the salt water, however, in the process the dehydration process kills the slug.  

Peyton Groshart
November 11, 2013 at 7:19pm

While teaching my mother about slugs and how fun it is to destroy them on a molecular level I gained an increased understanding on what it is that actually kills the slugs and that it's not the intake of salt but the loss of water be expelled out of their body that causes them to shrivel up and die.

Tyler Brenneman
November 11, 2013 at 9:29pm

Mom:  Basically I learned that salt (and salt water) can dehydrate a slug.  The salt pulls the water out of the slug. Surprisingly, water moves in and out of the cell but, more water pushes from the high concentration to the low concentration. Hypotonic is a term used to describe a cell with less salt compared liquids.  Hypertonic is a term used to describe a cell with more salt compared to liquids.

 

Tyler: In this lesson today, I taught my mom everything about what happens when a slug is put into an ocean. In no surprise, she already knew that salt messes with the slug and kills it. However, she did not what happened at the microscopic level, so I drew a picture explaining that to her. I think that the main point to grab from this lesson is that water moves from high concentration to low concentration.

Jon Neil (Instructor)
November 12, 2013 at 4:12pm

Thank you to all who contributed.  As both Tyler and Kelli mentioned, I would encourage students to use microscopic drawings to enhance your explanation of the process of osmosis is the slug analogy.  Be sure that your discussion hits upon the idea of Water Potential and the movement of water from a higher to lower Water Potential, as this is the key concept behind the salty slug problem.  I'm glad to see parents are finding useful strategies to tackle slugs in their gardens.

Brett Babbel
November 13, 2013 at 7:56pm

Mom: That the salt attracts the water from the slugs cell and causes it to shrivel and die. The plasma membrane is selective but water can always pass through through osmosis. Because the salt is in the air it makes it have a lower potential than inside the slug so the water goes from positive to negative. Learned that solutes decrease the water potential, water always follows solutes.

Student: I better learned that water will follow solutes. Also learned that the plasma membranes are selective and will always take or give water by osmosis so the water will go from high conc. to low conc. It helped me remember the importance of the of our bodies oils and why we use chaps tic and stuff to keep our water in and not letting it diffuse from osmosis. 

Danielle Agoh
November 18, 2013 at 7:15am

Student: I asked my mom if she knew why slugs were afraid of the ocean. Before she answered I recalled on her asking me a few days ago why the coconut lost its water from sitting out. She thought that there were no holes so the water should still be in the coconut. I saw this as a perfect opportunity to explain water potential in living cells. I told her because coconuts are living things; they were made up of cells. I explained to her that cells have cell membranes and water can move through them. Since thin air contained less water molecules than the coconut, the coconut water moved to the air because water potential moves from high concentration to low concentration. I drew a picture of how water concentration affects the movement of water molecules. This helped me better understand how water moves to a higher concentrated solution, but it moves to a lower concentration of water molecules.

 

 

Parent: One is NEVER too old to learn and my daughter, Danielle taught me something new today. A coconut had been lying in the fridge for quite some time now…..so long that it felt very light when I picked it up….all water “evaporated” through the shell. I was really stunned because I did not understand how water could seep through a hard shell that did not have any crack. Danielle was in the immediate vicinity and she explained the process to me. From what I understood, all living things, plants, animals, including human beings have cells that have membranes and water on its way from high concentration to a lower concentration(air) will move through those membranes. Hence, the coconut without water.

Francisco Perez
November 18, 2013 at 7:13pm

Parent: Today Francisco told me about slugs and how they would react in salt water. First, he told me that molecules move from a high to low concentration. And if slugs were put in water then the salt in the ocean water would move towards the slug which will eventually kill the slug (it will shrivel up). Also, he told me what hypertonic and hypotonic means. 

Student: I taught my mom about diffusion and how slugs would eventually die if they were placed in salt water. I told her that molecules move from a high to low concentration and since the salt water contains more solutes then the slug then that means the salt will move towards the slug. 

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