Osmosis Egg Lab Part 1

This week we had to implement a structured inquiry lesson. Since I am currently substituting I have been working with one of the 5th grade teachers at the school. The students had been learning about plant and animal cells. I thought it would be fun for the students to see how the cell membrane works and explore osmosis. The first day we watched the BrainPop video on Passive transport found here http://www.brainpop.com/science/cellularlifeandgenetics/passivetransport/.

I used the experiment listed as my demonstration to give the students some knowledge about osmosis. The experiment used peeled carrots; one carrot was placed in a bowl of water and the other was placed in a bowl of salt water. A third carrot was left out as a control. We checked the status of the carrots at the end of class, but then left them overnight. The carrot in the water became stiff and was hard to bend because the water diffused into the carrots cells. At the same time the carrot in the salt water the water diffused out of the cells and the carrot became soft and very bendable.

Now that the students were armed with some background information we could work on our osmosis lab. The first step was preparing the eggs- to do so eggs were placed in a cup and covered with vinegar. The vinegar produces a chemical reaction with the shell and leaving the egg surrounded by the membrane. The students massed the eggs and predicted what they thought would happen to the eggs. The eggs were then placed in various solutions including:

Distilled Water

Colored Distilled Water

Salt Water

Karo Syrup

and

Molasses

The eggs were left overnight. The next day we observed and massed the eggs. All of the eggs in the water solutions gained mass while the eggs in the sugary solutions lost mass. Here you can see the eggs that were in the molasses and the Karo syrup lost mass and left dents in the eggs.

The purpose of using the colored water was the show the students that it is the water that is entering the egg, they compared it to Easter egg dying as that is what it looks like.



Here is one last shot of a very bloated egg.

After all the observations had been made we popped the membranes to see what would happen. Those that were in the water solutions produced geysers as all the water came shooting out. The eggs in the sugary solutions did not do much since the water had diffused out of the egg. Unfortunately we ran out of time to finish up their calculations and conclusions so we will continue our discussion this week and give them time to create their posters demonstrating how osmosis works. Examples of student work will follow in a few days. The students have been very excited to do some hands on activities and the teacher would like me to continue to work with her on new ideas and she was ecstatic to see how her students responded to this activity.

The lab was initially found here:

Bilash, B. & Shields, M. (2001). A demo a day- Biology. Flinn Scientific.

Some other references for the lab came from one of my favorite sites The Science Spot found here

http://sciencespot.net/Pages/classbio.html#Anchor-eggs

Recently on the NSTA listserv someone was looking for kitchen science lessons and someone else shared this sitehttp://www.exploratorium.edu/cooking/index.html



Melting Icebergs

This week we have been asked to consider the implications of what happens if the polar icecaps were to melt.



Image via Vanity Fair

Could this be a stunning realization in the future? From what I have read it all depends on which icecaps are melting. From what I have read most of the ice is located on Antarctica in the South Pole and if it were to melt the sea level could rise by 61 meters, but the average temperature is around -37C and most of the continent never gets above freezing, so it seems the ice there is not being affected. The reason for the potential rise in water is due to the fact that the ice is on land. Moving to the North Pole the ice is floating in the water and the sea level would not be affected by the melting ice. Another potential problem is that the ice is mainly freshwater, while the sea is made of salt water. This would change the salinity of the water affecting the animals living in the water.

But what other consequences are there of the melting ice caps, especially those in the Artic?



Photo via Ebuam's World

The polar bears habitat is melting out from underneath them and there is evidence of polar bears drowning, starving and cub deaths. Even though the polar bear spends a great deal of time in the water, it needs the land for its lively hood. Also with the ice platforms moving father apart the swimming conditions are more dangerous. The polar bears are not the only animals affected by this. With the Artic ice melting, the cooling layer over the Artic is disappearing, the Earth then absorbs more sunlight and becomes hotter. This rise in temperature is creating an increase in the population a certain beetle in Alaska which is destroying millions of acres of the Alaskan forest. To me although there is problems with the polar icecaps melting, global warming in general is a problem

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What other questions do I have about this science inquiry experience?

• At what rate are the polar ice caps melting?
• Is there a way to compare and contrast the land ice melting vs. the ice floating in the water melting?
• How would the salinity be affected if this was conducted in salt water versus fresh water?
• What are ways we can prevent global warming and equalize the Earth's temperatures so there is neither and dramatic increase or decrease in temperature?

Solcomhouse

This topic is very interesting and I am looking forward to continuing my research into the matter of the melting icecaps and global warming in general. I hope we as a society can change our attitudes and start turning things around.

STEM Strategies

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This week we were asked to write a lesson plan using STEM strategies. I found this very challenging. Is there truly a way to incorporate Science, technology, engineering, and mathematics into the same lesson? The school I was teaching at in TX was suppose to become a STEM school, but the district decided to concentrate on the high school first. Implementing STEM in any school would require a lot of collaboration between the teachers involved. Although I have a background in science with a chemistry major and math as math minor I am not sure that I effectively integrated the math into the lesson well enough. Also at the moment the extent of adding technology is having the students create PowerPoints. While I have grown up around computers I still do not know how to use half of the things out there. I have worked around teachers that have had their students create movies on movie maker, creating podcasts among other things. I do not know where to start with these things. It would be wonderful if there was a course on how to incorporate technology into our lessons where we would experiment with what is out there. This is my first time attempting a blog and they have been a round for a while. I know other teachers have implemented them into their classes.

Another twist given to us was the use of the 5E's- engagement, exploration, explanation, elaboration, and evaluation. This process is similar to what we have used before. In TX we had to use very specific plans, and the focus was always more on the vocabulary and what we did as a teacher and what the students would do. I like the 5E format better as I feel we get to explain more of what the students will be doing. However I wish we had a little more explanation about how to implement each section. I am not sure if I applied each section correctly.

The lesson I wrote dealt with infectious diseases where the students would simulate a disease spreading and would try to figure out where it started from. They would be given some math problems to figure out that if an outbreak were to happen for real how it could affect the school, town, state and country. They would then work in groups and study an outbreak that has happened in the past, find out why it happened, what was done to stop the outbreak and what has been done to prevent future outbreaks. I would conclude by discussing careers that deal with infectious such as immunology and epidemiology. The main logistical issue would be working with the math teacher to try and figure out the problems or if there is an algorithm for the students to use for their calculations. Other than that I think the lesson would work out well.