Redeeming online time

It's so easy to fritter away time on the internet, visiting websites that have little educational value-so here are addresses of three well-executed, instructional websites that teach math, art history, and Hebrew.

• Go to Mathtv.com for videos that teach various math topics. Some of the short videos feature a teacher explaining the concept, while others show students solving and explaining problems on a whiteboard. You can click on different students to hear and see how they approach the problem. Videos teach basic math, trigonometry, algebra, and calculus-and it's all free, although you have to provide an email address in order to watch all the videos.

• My-Hebrew-Dictionary.com teaches modern day Hebrew through pictures and audio. Each picture is labeled with its Hebrew name written in Hebrew script, its transliteration, and its English name. Push a button and the narrator's clear voice pronounces the word. The website features short video slideshows on topics like animals and entertainment that allow you to quiz yourself, providing the name before the narrator does.

• Smarthistory.org is a lovely, free resource for people interested in art history: Its creators (professors Beth Harris and Steven Zucker) call it a web-book. The site includes 220 artworks that you can explore by style, artist, time period, or theme. The multi-media site combines images and text along with podcasts and videocasts of conversations about the art and artists that are more engaging than monologues tend to be. You can download podcasts related to particular paintings found in the Metropolitan Museum of Art, the Museum of Modern Art, and several others: Sound quality varies because some of the conversations are taped in the museums where the paintings hang.

A fourth website sponsored by the Newseum displays maps of the United States, Asia, Africa, Oceana, the Caribbean, Europe, the Middle East, and South America. A visitor can move the cursor to any city and a small image of the day's front page of that city's newspaper pops up. Click on the city and a larger image opens: newseum.org/todaysfrontpages/flash.

Ready to eat?

You know you've had that carton of eggs in your refrigerator for weeks (or maybe months). Are the eggs still safe to eat? How about the jars of capers or marmalade that you bought for that recipe and haven't used since? Stilltasty.com is a website devoted to answering the question: Save it or toss it? It provides shelf life information for thousands of foods, answers questions, and provides info on topics related to food safety.

And what if you have an old cell phone or DVD player? Wired magazine has compiled a list of places that will recycle or dispose of your old gadgets. Best Buy offers recycling at its stores, and some of the manufacturers listed will take your gadgets for a fee. One company will pay for recyclable material it can turn around and sell.

How about obscure movie titles that film buffs want to watch but mass audiences don't? Warner Brothers is opening its movie archives and allowing consumers to purchase for about $20 print-on-demand DVDs of movies that haven't been released on DVD: wbshop.com/Warner-Archive/ARCHIVE,default,sc.html).

Follow and be followed

You may have read in news stories of the role Twitter played in breaking the story of the US Airways plane landing on the Hudson or updating in real time the Mumbai terrorist attack. Recently protesters in Moldova used Twitter and Facebook to organize a demonstration that drew 10,000 people to a large square in the nation's capital to protest election results. On Good Friday, one New York church presented a Twitter passion play.

So what is Twitter? It's a social networking application that's also known as micro blogging because it requires messages ("tweets") to be short, consisting of no more than 140 characters. (See "Tweet, tweet," Nov. 1, 2008.) Twitter is organized around following and being followed. A user who follows a politician, for instance, will receive all the politician's tweets. Unless designated as a private tweet, Twitter messages are all public and can be tagged or labeled to be searchable. Twitter is also designed for use on cell phones as well as computers. The idea is fast interaction.

According to Scientific American, Google is interested in acquiring Twitter because it has a "large database of information, which expands daily in real-time. . . . Twitter also has a very effective search engine for mining this database, which would give Google plenty more web pages to sell to advertisers."

Watching Washington

Sunlight Labs is devoted to making messy government data useful to ordinary people. It recently sponsored its annual contest to encourage software developers to create applications for making "Congress more accountable, interactive and transparent." The group received 45 entries, which can be viewed at sunlightlabs.com/appsforamerica/apps.

For $19.99 the Chia Pet Company is offering something interactive but not transparent: a clay bust of President Obama along with chia seeds to smear on top. The growing seeds soon cover the figure with "hair" that eventually turns into a green afro. According to Wired.com, Walgreens has ordered stores in Tampa and Chicago to stop selling the ChiaObama because, according to a corporate spokesman, "We got some complaints from people that they thought it was racist."

Chia Pet creator Joseph Pedott, though, told FOXNews.com he was "shocked" by the Walgreens decision. Pedott, 76, said, "I'm sick about it. . . . It's Americana. I thought I would take the good name of Chia and support the good things that he's trying to do. . . . That was a labor of love." Pedott said he's a Republican but he voted for Obama.