Animal Diversity Web

http://animaldiversity.ummz.umich.edu/site/index.html

Butterfly Lab

Everything butterfly, including a field guide.

http://www.naturemuseum.org/online/thebutterflylab/index.htm

Or this one:
http://kidsbutterfly.org/

AWESOME lessons on science (mostly genetics)

This is a fantastic site. Entire lessons, completely online. Check out the "learning pathways" section.

http://www.nature.com/scitable

Insects--great insects site

http://www.insects.org/

Science Net Links

This is one of the best places to go for resources on science. I think I've posted their link before, but they recently re-designed their site, and all the materials are accessible now.

The "Tools" are my favorite--they are the best interactives from around the web.

http://sciencenetlinks.com/

Virtual microscope (free download)

This is developed by NASA and is very thorough.

http://virtual.itg.uiuc.edu/

Bugscope

http://bugscope.beckman.uiuc.edu/

You can schedule a time for a class (or, I imagine, a homeschool group) to have your own specimens shown to you through the scanning electron microscope. Or check out the archive.

Oceanography activities

http://www.fi.edu/fellows/fellow8/dec98/main.html

Insect activities

http://projects.edtech.sandi.net/grant/insects/

Partner Activities for the book "Stellaluna"

http://projects.edtech.sandi.net/chavez/batquest/batquest.html

Fun Abecedary

http://www.bemboszoo.com/Bembo.swf

Virtual Cat Dissection

Not for the faint of heart, but very very neat.

http://bio.bd.psu.edu/cat/

Kidwings: all about birds

This is a very cool site. Bird skulls, feathers, calls, feet, and more.

http://www.kidwings.com/index.htm

Virtual Owl Pellet Dissection

Very cool: http://www.kidwings.com/owlpellets/flash/v4/index.htm

Middle and High School Science Glossary (multilingual)

Middle School: http://www.glencoe.com/sec/science/mlg/mlg.php?site=19 

High School: http://www.glencoe.com/sec/science/mlg/mlg.php?site=20

Classic Lit .pdfs plus lessons

http://www.glencoe.com/sites/common_assets/literature/literature_classic_09/hs/index.html

http://www.glencoe.com/sites/common_assets/literature/pdfs/literatureclassicsms/ms/index.html

http://www.glencoe.com/sites/common_assets/literature/pdfs/literatureclassicshs/hs/index.html

These three sites are middle school and high school level literature in .pdf format. This is actual classic literature, from poetry to complete Shakespeare plays. There are no complete novels, but there are chapters of novels.

The databases are searchable by title, author, genre, "big idea" (thematic unit), date, country, or grade level, and there are lesson materials available.

Entire Units on Classical Literature

http://www.glencoe.com/sites/colorado/student/languageart/assets/index1_litlib.html

They are labeled "study guides," but these .pdfs are really entire units, complete with background, author notes, and worksheets.

Annotated Writing Samples (Guide to what your child should be doing)

These are really helpful guides to what an average, above average, and below average piece of student writing looks like in different types of writing for grades 6-12.

http://www.glencoe.com/sites/colorado/student/languageart/assets/indexann.html

Glossary of Math Terms

http://www.glencoe.com/apps/eGlossary612/grade.php

For grades 6-12, plus a section just for formulas.

Math Review Help

http://www.glencoe.com/sites/colorado/student/mathematics/assets/math_review.html

Math Problem of the Week

http://www.glencoe.com/sites/colorado/student/mathematics/assets/pow.html

Scientific Articles Archive

The explanation: http://royalsociety.org/news/Royal-Society-journal-archive-made-permanently-free-to-access/?f=1

and the archive: http://royalsocietypublishing.org/search

How to make a bracelet (or rope) out of plant fibers

Make a solar cooker

http://solarcooking.org/plans/Dublin_Ohio_class_project.pdf

or

http://www.hometrainingtools.com/build-a-solar-oven-project/a/1237/bhcd2/1262811159/

and recipes: http://www.hometrainingtools.com/images/art/SolarOvenRecipes.pdf

Free computer programming course

http://www.codecademy.com/#!/exercise/0

Free video sewing course

From bobbin winding to slash pockets, this has videos that cover basic and advanced skills.

http://sewingvideos.byu.edu/

Unit on peanuts

There is a lot of information here, plus some good science experiments.

http://www.innovativeclassroom.com/Downloads/ThematicUnits/Peanuts.pdf

Curriculum Bits Interactives

Interactives on all topics.  http://www.curriculumbits.com/resources/

Earth Systems Science Courses

Very cool resources here.

http://essea.strategies.org/modules.php?action=list&sort=bytopic

Bake Trilobite cookies (seriously)

http://www.georgehart.com/trilobites/trilobite.html

Earth Science Explorer Elevator

Explore a virtual earth science museum

http://www.cotf.edu/ete/modules/msese/elevator.html

Exploring the Environment

Lessons and activities, focusing on problem-based learning, on many topics in the environmental sciences.
http://www.cotf.edu/ete/modules/modules.html

Jefferson Labs

I've posted a link or two to Jefferson Lab before, but it's been a long, long time, and they are worth looking at again.

My kids love the liquid nitrogen videos.

But they have so much more.  Homework Help.  Games and Puzzles. Video lectures.

TONS of fun stuff. Jefferson Lab is science, and focuses on chemistry and physical science.

Earth Science Interactives

http://www.cotf.edu/ete/modules/k4/k4modules.html

K-4

Great lesson on why leaves change color in the fall

Written by a homeschooling mom with gifted children, this is an awesome lesson:

http://chastitywilson.blogspot.com/2011/10/autumn-homeschool-lesson-fall-leaves.html

and projects homeschoolers have done with fall leaves: http://pinterest.com/debchitwood/autumn-leaf-unit-study/

Kids Gardening--My First Garden

http://urbanext.illinois.edu/firstgarden/index.cfm

Unit plans--many subject, many levels

http://www.beaconlearningcenter.com/unitplan/Subject.asp

The Online Zoo

http://www.theonlinezoo.com/

Great Science Interactives

http://sv.berkeley.edu/showcase/index.html

Marine Habitats slide shows

There are video clips, slide shows, photo galleries, and lots of good information on marine habitats, including various coastal zones, here: http://www.barwonbluff.com.au/barwon_index.htm

Cool microscopic photography

http://www.boston.com/bigpicture/2011/10/nikon_small_world_photomicrogr.html

Free Open Courseware Writing classes

http://education-portal.com/articles/10_Universities_Offering_Free_Writing_Courses_Online.html

Science Podcasts

here: http://www.thenakedscientists.com/HTML/podcasts/

and here: http://radio.seti.org/pages

Another Link Aggregator

http://www.jennifererix.com/bookmarks/index.html

Novel Writing Courses, K-12--these are really good

Workbooks:

http://ywp.nanowrimo.org/files/ywp/ywp_10_es_workbook_3rd_edition.pdf   Elementary Level

http://ywp.nanowrimo.org/files/ywp/ywp_10_ms_workbook_3rd_edition.pdf  Middle School Level

http://ywp.nanowrimo.org/files/ywp/ywp_10_hs_workbook_3rd_edition.pdf  High School Level

And the Lesson Plans to go with them: http://ywp.nanowrimo.org/lesson-plans

Math and Science interactives

http://lgfl.skoool.co.uk/index.aspx

Lots of good stuff here.

AP Environmental Science

http://www.eoearth.org/article/AP_Environmental_Science_Online_Course

Virtual Fetal Pig Dissection

Fascinating, but not for the faint of heart.

http://www.whitman.edu/content/virtualpig

Virtual Historically Significant Books

This is one of the cooler resources I've found ever. You can actually look through virtual copies of many of the most historically significant books ever produced, including Mozart's notebook, Leonardo's notebook, Alice in Wonderland (the handwritten original copy), Mercator's atlas, the Lindisfarne Gospels, and many more.

http://www.bl.uk/onlinegallery/ttp/ttpbooks.html#

VERY impressive site.

Forests Unit

http://wupcenter.mtu.edu/education/Forest_Institute/Pregitzer_Finding_Out_About_Forests_2005.pdf

Newton's Apple Science Movies, lessons, and activities

http://www.tpt.org/newtons/

There are fabulous resources here!

Complete Unit on Oceans

http://www.usc.edu/org/seagrant/Education/IELessons/IELessons.html

PreK-2 Oceans Unit

http://www.seaworld.org/just-for-teachers/guides/pdf/ocean-discovery-prek.pdf

Marine Education Resources and Lesson Plans

http://web.vims.edu/bridge/?svr=www

Science behind our food Unit

For grades 3-12

http://apps.caes.uga.edu/sbof/main/showLessonPlanByQcc.cfm?qcc=25&subject=Biology

K-3 All about plants unit

http://www.saps.org.uk/primary/teaching-resources/539-plants-for-primary-pupils-booklets-overview

Pollinators Unit

http://pollinator.org/nappc/PDFs/curriculum.pdf

Web Currents Weekly Online Lesson

http://www.learnersonline.com/weekly/index.htm

Really cool webquest-style lessons.

Agriculture and Environmental Science Lesson Plans

http://www.khake.com/page81.html