Good Eats Fan Page
This lists both scientific and nonscientific themes covered in the episodes. Handy if you want to find an episode that covers a topic you'd like to use to enhance your classroom lesson.
Editor's Note: The link to this site may change. If the link is dead, please report it to me, and I'll try to fix it.
Note 2: Still not getting paid by anyone for mentioning the site. :)
Thursday, March 21, 2013
Celebrating 15 Years with the 15 Classroom Activities Greatest Hits from the Journal of Chemical Education
Free activities! These are written so you can use them in the classroom as soon as you've gathered the materials for the experiments. Many of them are quite clever in their use of materials to demonstrate a chemical property.
Celebrating 15 Years with the 15 Greatest Hits, 1997-2012
September 2012 marks fifteen years since the first classroom activity, "A Refrigerator Magnet Analog of Scanning-Probe Microscopy" was published in the Journal of Chemical Education.
112 Activities later - readers are still finding these activities attractive and useful; with their use of materials available from local grocery and hardware stores, wide range of chemical concepts covered, a ready-to-photocopy-and-use format, and the knowledge that each one had been tested by fellow teachers. Many of the activities require a subscription to JCE, but others do not. Here's a link to more information about the 15 greatest hits.
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Medicine safety: Are these caplets the same or different?
Not the best photo, but do you think that these caplets are the same or are there differences? What observations could you make to determine if they are the same or different? The answer will be revealed soon.
This was a little thought experiment I came up with while I was at the Hoosier Association of Science Teachers Conference. :)
Sent from my Windows Phone
How to turn a room into a camera....don't you want to try it?
Turn a room into a camera: Cool optics experiment idea
This could be such a cool optics experiment in a classroom. I could imagine getting a few large boxes (refrigerator size or bigger), taping them together, then creating the set up as described. You could try different lenses to see how that changes the image as well as their suggestion to change the aperture, or the amount of light, that goes through the lens. it would be neat to set it up so the lens could pick up the movements in the school, like in a cafeteria, so you could have a video camera set up to capture the images over time, then do a time elapse of the video to speed up the motion vs. time.
Editor's note: When I get excited about an idea, I tend to write really long run-on sentences. Sorry.
Note 2: I haven't been paid by anyone to share this idea or websites associated with it.
Note 3: I think I may have to build one myself. This could become a very cool traveling experiment for family science nights. The key will be to 1) get extraneous light blocked out, and 2) make it durable, and 3) make it easy to assemble and disassemble.
This could be such a cool optics experiment in a classroom. I could imagine getting a few large boxes (refrigerator size or bigger), taping them together, then creating the set up as described. You could try different lenses to see how that changes the image as well as their suggestion to change the aperture, or the amount of light, that goes through the lens. it would be neat to set it up so the lens could pick up the movements in the school, like in a cafeteria, so you could have a video camera set up to capture the images over time, then do a time elapse of the video to speed up the motion vs. time.
Editor's note: When I get excited about an idea, I tend to write really long run-on sentences. Sorry.
Note 2: I haven't been paid by anyone to share this idea or websites associated with it.
Note 3: I think I may have to build one myself. This could become a very cool traveling experiment for family science nights. The key will be to 1) get extraneous light blocked out, and 2) make it durable, and 3) make it easy to assemble and disassemble.
Saturday, February 2, 2013
Science at Home: How to Ripen Fruit Quickly
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| Banana, Pear, and Golden Delicious Apple ready to eat |
Science at Home.
Photo from my own kitchen.
Have some pears or apples that aren't quite ripe enough to eat? If you have a banana handy, use this simple trick to speed up the ripening process of the fruit so you can enjoy it sooner.
Experiment:
Put a banana and your other fruit in a plastic bag (not completely sealed) or a brown paper bag. Wait. How long it takes for the fruit to ripen will depend on how hard it was to start with.
You can also use a ripe apple to ripen other fruits using the same process. This works well with peaches, plums, and other stone fruits when placed in a paper bag.
How does it work?
Even though the fruit has been picked, the cells within it are still alive! Starch in the fruit gradually converts to glucose , a sugar, when certain enzymes are present. If you've ever tried to eat a pear before it was ripe, you probably noticed that not only was it very hard but it also wasn't sweet. That's because the starch hadn't yet converted to sugar, which is part of what makes fruit taste so yummy.
Ethylene is a gas that is made by some fruits, and it triggers the ripening process. Ethylene acts like an enzyme by speeding up the conversion of starch to sugar. Bananas make lots of ethylene as they ripen. The ethylene gas that comes out of the banana is trapped in the bag, exposing the other fruits to extra ethylene. The extra ethylene then triggers the ripening process for the pear and the apple. Apples also produce a lot of etylene, and that's why they can also be used to ripen other fruits.
This doesn't work for all fruits. Some fruits ripen by other processes, like grapes and cherries.
What happens if fruit is exposed to too much ethylene?
Fruits that make ethylene to trigger ripening do not stop making ethylene once the fruit is ripe. They will continue to make ethylene, and the fruit will continue to get softer and softer, with more and more sugar, and will eventually be rotten.How do you like your banana?
Bananas have many levels of ripeness and people often disagree about which one tastes best. Some people like them slightly green, when they have a bit of sweetness but are still quite starchy. At the other extreme are people who love bananas with lots of dark brown spots. These bananas are much softer and very sweet. They may have bruises caused by the fruit getting injured, which causes the ripening process to be accelerated at those spots.Did you know?
Bananas are picked very green and shipped in containers pumped with ethylene gas. Supposedly some grocery stores also have chambers to ripen fruit with ethylene before putting it in the produce area for sale. The ripening process can be stopped during shipping by stopping the addition of ethylene to the shipping containers.
Other Resources:
This website has a nice diagram showing the chemicals that are involved as fruit turns from being unripe to ripe.
http://plantphys.info/plants_human/fruitgrowripe.shtmlA more detailed explanation of how ethylene contributes to the fruit ripening process.
http://postharvest.tfrec.wsu.edu/pages/PC2000F
Nice resource about the ripening process for many fruits from a company that makes machines that produce ethylene safely for container ripening. The banana section has a chart showing bananas at several stages of ripening.
http://ripening-fruit.com/banana
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