University Corporation for Atmospheric Research
Ucar: Just a Phase: Water as a Solid, Liquid, and Gas
This site helps students construct a model of the arrangement of water molecules when present as solid, liquid or gas. Includes background information, lesson plans, links to standards and assessment ideas.
CK-12 Foundation
Ck 12: Earth Science: Scientific Models
[Free Registration/Login may be required to access all resource tools.] Recognize the uses, limitations, and different types of scientific models.
Rice University
More Fun Fractions
In this site, pattern blocks are used to explore fractional relationships among shapes.
University of Cambridge
University of Cambridge: Nrich: Path to the Stars
See if you can solve this challenge with a 5 point star. What about a 6 point star? 7? 8? 9? The one page website gives you the solution so that you can check your answer.
University of Cambridge
University of Cambridge: Nrich: Three by Three
Push your problem-solving skills to the limit. Arrange 3 red, 3 blue and 3 yellow counters into a three-by-three square grid, so that there is only one of each color in every row and every column.
University of Cambridge
University of Cambridge: Nrich: On the Edge
On which polyhedra are you able to trace along the edge without retracing any edge? When you have found the correct polyhedra then check the solution provided for you right at this one page NRich website.
University of Cambridge
University of Cambridge: Nrich: Single Track
See if you can figure out how to get two trains on a single track past each other using only a very short siding. Check your results right on this one page websites to see if your answer works.
University of Cambridge
University of Cambridge: Nrich: Two Dots
Sharpen your problem-solving skills with this challenge that has you place dots on a diagram so that only two are on each straight line.
Other
Visual Fractions: Rename in Higher Terms With Circles
Practice renaming fractions in higher terms using circle fractions, in this Java applet interactive game. A simple activity for most. However, if you get stuck, see the detailed, directions and examples that are included.