Quizlet Vocabulary Game, M5
Videos, etc. for M5,
Part A
Videos, etc. for M5,
Part B
This module was a lot of fun! We did 4 experiments and one game. =)
We played a game as a preview before they began the module. I knew they would need to really understand structural formulas of molecules or
their eyes would fall out of their head when they turned the page and saw this! →
And that was just the
small molecule!
You may be more familiar with the formula for glucose being written this way: C
6H12O
6
They played team against team, winning points for their
2nd contest. Rebekah & Cousin
C vs. Isaac & Cousin
A. We played the chain structure first, since it definitely was easier, then the ring structure. Sometimes one team would be finished and I would check their work, and an atom was out of place and the other team would win! They had a lot of fun. We reviewed where to put the atoms a few times, then had one practice round.
Finally we began, and after 5 rounds, Rebekah and Cousin C's team won 150-100. The fastest time for chain structure was 21 seconds, but the fastest for ring structure was only
25 seconds! I thought it would be more.
Experiment 5.1, Diffusion was done at home. The kids put a spoonful of sugar in a napkin and brought the edges up and secured with a twist tie, making a little sac so that no sugar could seep out. This was immersed in a glass of water for a minimum of two hours. The purpose of this experiment was to show that water molecules could flow freely through the napkin, and that sugar, once dissolved was able to flow through the napkin too. This illustrated
diffusion.
In diffusion, both the
solvent (water) and the
solute (in this case, sugar) are able to flow through the
fully permeable membrane (napkin). Solutes naturally move from an area of high concentration (in the napkin) to an area of low concentration (outside the napkin).
Solutes moving from an area of high concentration to an area of low concentration is diffusion. In the end, the concentration of sugar to water evens out
in the napkin as well as
outside the napkin. However, the water level inside the napkin (fully permeable membrane) and outside the napkin stayed the same. Remember, this random movement of molecules will continue even after everything is equaled out.
The next experiment was done at home as well. It took several days. In
Experiment 5.2, Osmosis, the kids were to measure a raw egg, then place it in vinegar for 24 hours. The vinegar dissolved the shell, and if it wasn't fully dissolved, they were to place the egg in fresh vinegar for another 24 hours. Then it was to be measured again, and placed in Karo syrup for 24 hours. Then measured again, and placed in distilled water for the last 24 hours.
This experiment showed the difference between diffusion and osmosis. In
diffusion, water molecules and the sugar that was broken down were
both able to pass through the
fully permeable membrane, the napkin.
In
osmosis, only the solvent (water) has molecules small enough to be able to pass through the
semipermeable membrane, the membrane of the egg. The solute was the 'stuff' inside the egg. When the egg was placed in vinegar, the water molecules that are in vinegar could pass through the membrane. This made the egg grow larger.
When the egg was placed in the Karo syrup, not only did the water that was in the vinegar come back out of the egg, but water from the egg came with it. This is why the egg had shrunk. This shows something very important. Water is not just
leaking out... it is seeking the
higher concentration of solute. It is gravitating to the Karo syrup because it has a higher concentration of solute. Just like if you lay a sponge on a puddle of water, it doesn't just wet the bottom of the sponge; it soaks up into the whole sponge.
 |
| Osmosis |
The tendency for a solvent (the water)
to move from an area of low concentration across a semipermeable membrane to an area of high concentration is osmosis. Solute cannot cross a semipermeable membrane, so in an effort to balance it out, the solvent (water) will cross the semipermeable membrane to dilute the solute as much as possible.
Water, a solvent, will always gravitate to the higher concentration area, trying to even out the solvent to solute ratio.
This is why when a person drinks ocean water, the water in their cells will move out of the cell by osmosis to the higher concentrated salt water, which can be fatal.
When placed in the distilled water, I bet you know by now the egg swelled up again. But this time it grew much larger than it did when in the vinegar. This is because vinegar has more solute than water in it. We used distilled water to make sure there would be no solute in it.
 |
| choppin' cabbage |
I was glad I still had the leftover distilled water, for it worked right in with one of our experiments this week,
The Cabbage pH Indicator. We had learned about pH, and I wanted the kids to see this amazing experiment.
They boiled red cabbage (cut into large pieces) in distilled water for about 10 minutes. Cousin A labeled cups with the different substances we would be testing. Some needed to be mixed with distilled water. (baking soda, washing soda, salt, sugar, and lye soap) For the dry ingredients, they mixed 1 Tbs. with ¼ c. distilled water, and for the lye soap, we just rubbed some off, maybe ½ tsp., and mixed until it melted.
I had them make sure to use a clean, dry spoon each time they measured or stirred. Glad we were next to a sink! =)
Other liquids we tested were milk, lemon juice, vinegar, ammonia (
whew!), distilled water, and my tap water. We didn't have any rain water.
Then we strained the cabbage juice that had been boiling; it was dark bluish-purple. They added about 1 Tbs. of cabbage juice to each of the cups. In the videos, you can see it is still hot!
Isaac wrote down all the substances that were to be tested, then Rebekah wrote the results as they did them. I made copies of this page for the all kids to use at home when they did their lab reports.
Here is what happened:
The end result:
The blue, bluish-green, and yellow-green are bases, and the pinks are acids.
I would say the salt is somewhat of a base, even though it is lighter, and a little bluish purple.
The distilled water is neutral. It is more clear than it appears in the picture.
We also did
Yummy DNA! I saw this last year at
Applie's Place. Here is the link to the
original instructions.
The kids worked carefully, as they held their lives in their own hands, making sure to link the correct
nucleotide bases together:
adenine with
thymine, and
guanine with
cytosine. They used different colored "backbones" to make the sides of our double helix, as our DNA is all different, right? (and much tastier this way, too!) The backbones of DNA are made up of
phosphate groups (arrangements of phosphorous, hydrogen, and oxygen atoms) and
deoxyribose (a simple sugar that contains 5 carbons). These alternate down the sides of the double helix, but aren't shown in the experiment.
Click for a cool
DNA game. =)
We had a great time today! Even with the smelly ammonia and cabbage, lol.
