Leaf Disk Lab

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Better late than never, I guess. Followers of Catholic Christian Homeschooling Facebook Page saw a preview of this post with the statement: I would update the blog later today or tomorrow. Well, today and tomorrow came and went -- they are long gone, the post wasn't done within the promised time frame, but it's here now.

This year our science focus has been biology. The topic this past week was photosynthesis. I try to have her do hands on labs as much as possible to go with the course work -- I still need to get a decent microscope, but we have found other labs to do that don't require a microscope. One of them has been the leaf disk lab. When you google search and look on youtube there are several tutorials on this lab.  The two videos we based our lab on was the following videos:













The second video talks about adding detergent to the mixture. We did not do this! We did use spinach leafs and soaked them overnight like the first video suggested. We pulled the oxygen out of spinach leafs according to the second video (it looked easier to do) and dumped them into a contain of more solution -- we also felt this was easier to do -- seeing we didn't have a real good way to keep the syringe in an upright position.

If we were to do the lab all over again we would have done a second patch of leafs without the light. So time could be compared between having the light and NOT having the light.

Our Lab:

• 2 Measuring Cups (2 cups and 1 cup)
• Baking Soda
• Water
• Spinach Leafs (left to soak overnight)
• Container To Soak Leafs In
• Oral Dosing Syringe
• Hole Puncher 
• Light
• A Means To Keep Time (we just used the timer on my daughters iPod touch -- but any device that has a time would work)

I went to the store and bought a package of spinach leafs. I soaked a handful of them overnight in some cold water. -- we used the rest of them for a dinner. :D

After the leafs soaked overnight we used a hole punch to punch out leaf disks. We punched out about 20 of them. We then put them in an oral dosing syringe with the solution of baking soda and water.

For the solution, we mixed 2 cups of water with a dash of baking soda. I actually own measuring spoons that say drop, dash, pinch, etc.

After the leafs and solution were mixed we followed the instructions on the second video and started to extract the air, oxygen, from the leafs; as we did this we could see them fall to the bottom of the syringe.

We then dumped them into a 1 cup measuring cup that had more of the baking soda and water solution and turned on the light! We actually did the whole process several times and after about 5-10 minutes we had at least 5 disks floating on top of the solution.  -- like I said if I could have done it again I would have done it without the light too so we could compare time with the light and without the light.

This is a pretty straightforward lab and I believe it to be good hands on experiment on how photosynthesis works. Of course, it requires talking about photosynthesis and what is going on with the leafs and why the change from floating and not floating. :D

This also lead to the discussion on how different labs are set up to test or show different things. Doing all of this reminded her how long ago when she was younger we did labs that showed mass by floating and sinking -- What a fun discussion that was too!

Oh, and the very first picture was just Web-Princess being silly and goofy. She was hamming it up some for the camera -- especially seeing she knew it was going to be posted here.  She may still ham it up for the camera, but her being a teen matters -- she changed clothes before I was allowed to even snap pictures. She didn't want her in her other clothing, her lounge at home clothing,  mind you just a tshirt, to be on the blog.  She didn't want to people to see her in this tshirt. It's just a tshirt. :D