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  • Populations

Browse by Grade & Topic: Populations

Find Gizmos organized by grade level and topic.

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Estimating Population Size

Adjust the number of fish in a lake to be tagged and the number of fish to be recaptured. Use the number of tagged fish in the catch to estimate the number of fish in the lake.

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Rabbit Population by Season

Observe the population of rabbits in an environment over many years. The land available to the rabbits and weather conditions can be adjusted to investigate the effects of urban sprawl and...

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Effect of Environment on New Life Form

Using the scientific method, control the environmental conditions for a fictional alien organism in order to learn how the organism responds to changes in conditions. Sunlight, water, and...

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Temperature and Sex Determination

Observe the sex ratios of birds and geckos as they hatch in an incubator. Vary the temperature of the incubator and measure the percentages of male and female hatchlings to determine if...

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Temperature and Sex Determination - Metric

Observe the sex ratios of birds and geckos as they hatch in an incubator. Vary the temperature of the incubator and measure the percentages of male and female hatchlings to determine if...

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Natural Selection

You are a bird hunting moths (both dark and light) that live on trees. As you capture the moths most easily visible against the tree surface, the moth populations change, illustrating the...

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Rainfall and Bird Beaks

Study the thickness of birds' beaks over a five-year period as you control the yearly rainfall on an isolated island. As the environmental conditions change, the species must adapt (a...

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Rainfall and Bird Beaks - Metric

Study the thickness of birds' beaks over a five year period as you control the yearly rainfall on an isolated island. As the environmental conditions change, the species must adapt (a...

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Ecosystems

  • Stem Case

As a national park ranger, students must restore the ecosystem of a park back to normal. They interact with populations of many organisms including wolves, deer and bees. Students learn the...

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Animal Group Behavior

  • Stem Case

A farmer in Africa is having problems with elephants eating her corn and cotton crops. As a wildlife biologist, students learn about animal group behavior and relationships of elephants and...

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River Detective: The Case of the Missing Shad

  • Stem Case

FREE with no time limit!

An important fish species, the American Shad, has disappeared from the James River in Virginia. Students take on the role of a junior River Watch member to investigate the shad population’s...

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River Detective: The Case of the Missing Shad

  • Stem Case

FREE with no time limit!

An important fish species, the American Shad, has disappeared from the James River in Virginia. Students take on the role of a junior River Watch member to investigate the shad population’s...

Lesson Info STEM Cases

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About STEM Cases

Students assume the role of a scientist trying to solve a real world problem. They use scientific practices to collect and analyze data, and form and test a hypothesis as they solve the problems.

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Each STEM Case uses realtime reporting to show live student results.
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STEM Cases take between 30-90 minutes for students to complete, depending on the case.

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© 2025 ExploreLearning. All rights reserved. Gizmo and Gizmos are registered trademarks of ExploreLearning. STEM Cases, Handbooks and the associated Realtime Reporting System are protected by US Patent No. 10,410,534

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Find Gizmos
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© 2025 ExploreLearning. All rights reserved. Gizmo and Gizmos are registered trademarks of ExploreLearning. STEM Cases, Handbooks and the associated Realtime Reporting System are protected by US Patent No. 10,410,534

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