Curated OER
Geometry: curves
In this curves instructional activity, learners identify the curves in the shapes given as being either closed or open. Students complete 5 problems total.
Science Education Resource Center at Carleton College
Serc: Electric Circuits Guided Inquiry
An electrical circuit guided inquiry where middle schoolers investigate what an electric circuit is, the main parts of a circuit and the difference between series and parallel circuits. Students groups create a circuit using materials...
National Council of Teachers of Mathematics
The Math Forum: Ask Dr. Math: Closure
Dr. Math explains the algebraic concept of closure. Dr. Math gives several examples and explains why the set is closed under the operation or not.
Oswego City School District
Regents Exam Prep Center: Closure Property
This site gives a very clear discussion on the topic of closure of sets over an operation with many examples.