In this Illuminations lesson, students apply their knowledge of addition equations to investigate the equivalence of two numeric expressions using the "Pan Balance-Numbers" applet (cataloged separately). An instructional plan, questions for the students, assessment options, extensions, and teacher reflections are given for the lesson as well as links to the applet and a student activity sheet(word format).

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.

In this activity, students research various topics about ocean health, e.g. overfishing, habitat destruction, invasive species, climate change, pollution, and ocean acidification. An optional extension activity has them creating an aquatic biosphere in a bottle experiment in which they can manipulate variables.

Explore stretching just a single strand of DNA using optical tweezers or fluid flow. Experiment with the forces involved and measure the relationship between the stretched DNA length and the force required to keep it stretched. Is DNA more like a rope or like a spring?

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

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.

What happens when sugar and salt are added to water? Pour in sugar, shake in salt, and evaporate water to see the effects on concentration and conductivity. Zoom in to see how different sugar and salt compounds dissolve. Zoom in again to explore the role of water.

In this math lesson, learners practice addition facts (with sums of 5, 6, 7, and 8) in a concentration-game format using dominoes. Then, learners generate sums of given numbers using a calculator, record the sums on a hundreds chart and look for patterns. This lesson guide includes questions for learners, assessment options, extensions, and reflection questions.

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?

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

In this video adapted from Earth Island Institute, meet a high school student who educated her community about how a coal-burning power plant was contributing to asthma and other health problems there.

Thinking about numbers using frames of 10 can be a helpful way to learn basic number facts. The four games that can be played with this applet help to develop counting and addition skills. (This applet works well when used in conjunction with the Five Frame applet.)

Prior to reaching households, water is exposed to a variety of treatments designed to render it fit for human consumption and use. One of the first treatment steps is the removal of suspended solids using chemical additives called flocculants. In this activity, students learn about two commonly used flocculants and clean water collected from a local pond or river. They experiment with flocculant, stirring and pH variables.

This investigation is a year round study of the phenology of a schoolyard.

An interview with biologist David Pearson, an author and expert on tiger beetles. Did you know that tiger beetles can run so fast that they go blind and just what would it be like to be hunted by these tiny, but ferocious animals? These are a few of the questions that we learn the answer from our guest biologist.

This animation produced by WGBH and Digizyme, Inc. demonstrates the experimental technique used to introduce DNA plasmids inside bacterial cells, a process called bacterial transformation.

The students will observe a maple tree throughout the year and recognize changes in weather and phenology using their 5 senses.