In this lesson, students will explore the causes of water pollution and its effects on the environment through the use of models and scientific investigation. In the accompanying activities, they will investigate filtration and aeration processes as they are used for removing pollutants from water. Lastly, they will learn about the role of engineers in water treatment systems.

This lab demonstrates Hooke's Law with the use of springs and masses. Students attempt to determine the proportionality constant, or k-value, for a spring. They do this by calculating the change in length of the spring as different masses are added to it. The concept of a spring's elastic limit is also introduced, and the students test to makes sure the spring's elastic limit has not been reached during their lab tests. After compiling their data, they attempt to find an average value of the spring's k-value by measuring the slopes between each of their data points. Then they apply what they've learned about springs to how engineers might use that knowledge in the design of a toy that enables kids to jump 2-3 feet in the air.

In this video profile produced for Teachers' Domain, meet conservationist Steve MacLean, an Inupiaq from Barrow, Alaska, who works to preserve the health of the Bering Sea ecosystem.

In this activity, students build a water filter with activated carbon, cotton and other materials to remove chocolate powder from water.

Students are introduced to Hooke's law as well as stress-strain relationships. First they learn the governing equations, then they work through several example problems, first individually, then as a class. Through the lesson's two-part associated activity, students 1) explore Hooke's law by experimentally determining an unknown spring constant, and then 2) apply what they've learned to create a strain graph depicting a tumor using Microsoft Excel®. After the activities, the lesson concludes with a stress-strain quiz to assess each student's comprehension of the concepts.

Short demonstration on scientific notation by asking students to place numbers on a number line using string and notecards.

This animation adapted from Garland Science Publishing takes a close look at the DNA double helix and its individual components, describing their chemical structures and how they function together to make the DNA molecule unique.

A POGIL activity regarding cellular respiration with an additional activity regarding the function of NAD+ in redox reactions.

Studying life on the seafloor beneath Antarctica's thick ice is a major challenge for ecologists. Learn about a new device that can reach those icy depths in this video segment adapted from WomenInAntarctica.com.

Many people do not like spiders and consider them pests. However, spiders provide a service to humans. They eat many of the insects that bother people. In this 7th grade life science activity, students will study 4-6 spider webs and discover what and how much spiders eat. They will identify the spiders building the webs, collect data and make observations related to the webs and what the spiders eat. They will use the information to develop a conclusion.

This article provides elementary school teachers with background knowledge about science concepts needed to understand the first of seven essential principles of climate literacy--the sun is the primary source of energy for our climate system. Graphs, diagrams, and oneline resources provide more background for the teacher. The article appears in a free online magazine that focuses on the seven essential princples of the climate sciences.

This video segment from FRONTLINE/NOVA: "Harvest of Fear" explores genetic modification of salmon and possible consequences.

In this lesson designed to enhance literacy skills, students learn about the varied physical and behavioral adaptations that animals rely on to help them survive changing environmental conditions, such as the arrival of winter.

This video segment adapted from NOVA reveals how junk DNA helped solve an evolutionary mystery: Why do certain species of fruit flies have wing spots while others don't?

The peacock provides a classic example of sexual selection, the force behind nature's extravagances. From Evolution: "Why Sex?"

In this video segment adapted from NOVA scienceNOW, microbiologist Bonnie Bassler shares her discovery that bacteria coordinate group activity by communicating through chemical signals. [4:49]

This video segment from the Nevada Department of Wildlife looks at tarantulas' survival skills and their habitat.

Bonnie Chen builds on students' prior knowledge of mutations to lead her class through a simulation of wading birds feeding.

Marilyn Havlik leads students through a simulation of the Hardy-Weinberg Principle to develop their understanding of population genetics.

This activity uses DNA sequences, protein sequence, and chromosome-density maps to re-trace the ancestry of humans and some of their closest relatives.