In Science Class . . . Week of 1/24

This week in science, we've continued our learning about how plants make energy (and gain mass) and how other organisms use that energy. We did an experiment with yeast. By giving the yeast sugar (in the form of crumbled up Chips Ahoy cookies), they became active and started cellular respiration. This process produces carbon dioxide as a waste product, which caused our bags of yeast and warm water to puff up! We used a tool to measure that gas produced as well as the amount of gas produced by the control experiment (no cookies), which was zero in most cases.
Key questions to ask your student:

• What organisms make their own energy? How can we tell that they are making energy? (Gain mass, grow)
• In the experiment with yeast, how did we know that the yeast were burning sugar? (They produced carbon dioxide as a waste product)
• Can you think of other organisms that produce carbon dioxide as a waste product of cellular respiration? (Most animals, including humans!)

In Science Class . . . Week of 1/17

The 4th and 5th graders have been wrapping up our study of vascular plant systems. We watched a video on plant structure and growth earlier this week, and yesterday, we studied different vein patterns in leaves we found around the school yard. Thanks to the huge wind storm, there were a ton of great options around! Here are some examples:

Palmate:

Pinnate:

Parallel:

Key Questions:

• How do vascular plants get water and sugar to cells? (Xylem transports water up from the roots, while phloem transports it downward to other cells. Both xylem and phloem are part of "veins" that we see on leaves.)
• What leaf patterns did you see in your leaves that you collected?

In Science Class . . . Week of 1/10

Hi, everyone! Happy New Year! Apologies for not getting this out to you last week. We had a major power outage during the time I normally update the blog! Anyway, here's what we have been working on:

We've just wrapped up our human body systems and have started looking at the ways plants get energy, water and gas to their cells. This week, we've been experimenting on celery. We set up an experiment to see which type of celery uses more water - celery with leaves or celery without leaves. Students also got to put red food coloring in the water so that we could track the flow of water up the stem and into the leaves. Here are some key questions:

• What do plant and animal cells have in common? (All need food, water, gas exchange and waste disposal)
• How do vascular plants transport water? (There are tubes in vascular plants called xylem that bring water from the bottom up into the leaves. These tubes turned red in our celery experiment due to the red water we used.)
• What would be analogous in the human body to xylem in plants? (Probably our circulatory system of veins and arteries, though we obviously have a heart that pumps it around, while plants depend on evaporation out of the leaves to draw water upwards.)
• What did you find from your experiment? (Celery with leaves used more water. This is because the evaporation out of the leaves "pulls" water molecules from below. )

Here's a nice cross section photo of what we worked on. This photo also includes some celery where blue food coloring was used. We only used red, but using other colors would be a great at-home project!