Day 4: LAB DAY! Diffusion and Osmosis

Guess what you guys! There were more pretty colors in today's lab!

So last night's homework was to go through and read this long arduous online chapter about diffusion and osmosis and to be quite honest, it didn't really make much sense until I actually got to class and things were explained to me in a different way.

So diffusion is when any molecule "travels" from a place of high concentration to a place of low concentration.

Osmosis on the other hand, is basically the exact same thing, except it's only when water moves from a high concentration of water to a lower concentration of water.

When two solutions are equal in their solute concentrations, the solutions are isotonic. The purple hexagon is the solute in these two solutions. Since both molecules have the same concentration in both solutions, the solutions are isotonic.

When solutions are not isotonic, the solutions are either hypotonic or hypertonic. Hypotonic solutions are the solution with a lower molecular concentration while hypertonic solutions have a higher molecular concentration.

Here's is my bio teacher's explanation beautifully drawn on the board.

So once we reviewed our reading and the slow people like me understood what was going on, we dove straight into our lab where we got to see osmosis happen. And today, my lab partner was once again, the fabulous Michelle. 

For our first part of the lab, we had six different colored liquid substances in which we were to find the molarity. We filled dialysis tubes with 7mL of each substance, weighed the initial mass, and left it in a cup of 25mL of distilled water for half an hour. Here's what it looked like right when we put it in the water.

It looked exactly the same. 

It looked the same when the coloful tubes were in the cup, but when we took them out to weigh them again, the weight changed. 

A lot of the different colors gained mass, meaning that there was more water molecules in the distilled water than in the tube. The blue one however, lost a little bit of mass, meaning that there was more water in the tube than the distilled water. The rest of the class got similar data to ours. Through the compilation of all our groups, we found that the blue colored substance was actually distilled water and had a molarity of zero. The reason why some groups may have gotten something other than zero could have simply been because of when the substance was weighed. Molecules don't just stop moving once they become isotonic. There is a constant motion of molecules (molecular motion). Some other groups like us just happened to weigh it in mid-motion. 

The next part of our lab was to put in 25mL of the colored substance into a cup and soak either a potato or a dialysis bag filled with a sports energy drink. Michelle and I decided to take on the challenge of filling six dialysis tubes with orange flavored Vitamin Water. 

 We were then told to leave it in a spot in the room and come back during the evening lab hours, which was 7 hours and 20 minutes after class ended! And for a day student, that's a lot of time on campus. But I prevailed and I actually got some other homework done while waiting for labs to start. (And my tennis team won their match so yay!)

Okay fast forward to evening labs and our cups are exactly where we left them. The results were extremely different from the first part of the lab. For most of the Vitamin Water, the mass decreased, except for the one with the blue colored substance and the clear substance. Those had gained mass. 

But that was basically it. We got to witness osmosis and diffusion firsthand and figure out molarity all while using pretty colors, just to make life more interesting. So now I must proceed onto the other realms of study, which is fancy talk for "It's time to study for my French quiz tomorrow otherwise I'm going to fail."

Until next time, stay cool or stay warm whatever suits your needs and DFTBA (Don't Forget To Be Awesome)