In this advanced simulation, students experiment with changing the ion ratios in solutions and thus the pH. The experiment can be viewed on a macroscopic or microscopic level, or customized.

In this simulation, students learn how changing the concentration of a solution affects the pH level.

In this video from Cyberchase, the CyberSquad helps Ms. Fileshare realize that Hacker has been deceiving her as they take a look at the scale of a bar graph.

In this video, life-size replicas help demonstrate one-dimensional scaling and the ratio relationship between two real-world quantities. The accompanying classroom activity helps students understand how ratios and proportions can help them determine an unknown height.

This video features the Louisville Slugger Museum and Factory, home to the world's largest bat. Students see the role that measurement and engineering play in making bats to professional players' specifications and are asked to consider the ratio relationship between the big bat outside the museum and a standard-size bat. In the accompanying classroom activity, students use proportional reasoning and equivalent ratios to determine how tall a statue of a ballplayer would have to be to match the height of the big bat.

Students build scale models of objects of their choice. In class they measure the original object and pick a scale, deciding either to scale it up or scale it down. Then they create the models at home. Students give two presentations along the way, one after their calculations are done, and another after the models are completed. They learn how engineers use scale models in their designs of structures, products and systems. Two student worksheets as well as rubrics for project and presentation expectations and grading are provided.

This video tutorial [5:22] explores how objects are represented in a scale drawing to show they are similar. Assess learning with a quiz.

This interactive will present the varying applications of the powers of ten within
the metric system to measure the lengths of objects invisible to the eye and
objects out of this world.

Students learn how different characteristics of shapes—side lengths, perimeter and area—change when the shapes are scaled, either enlarged or reduced. Student pairs conduct a “scaling investigation” to measure and calculate shape dimensions (rectangle, quarter circle, triangle; lengths, perimeters, areas) from a bedroom floorplan provided at three scales. They analyze their data to notice the mathematical relationships that hold true during the scaling process. They see how this can be useful in real-world situations like when engineers design wearable or implantable biosensors. This prepares students for the associated activity in which they use this knowledge to help them reduce or enlarge their drawings as part of the process of designing their own wearables products. Pre/post-activity quizzes, a worksheet and wrap-up concepts handout are provided.

Students learn how to determine map distances and areas using the map scale. They get a feel for how much an area represents on the map in relation to the size they are suggesting for their underground caverns to shelter the Alabraska population.

Students are introduced to the concepts of graywater and water reuse within households. They calculate the amount of used water a family generates in one day and use a model of home plumbing to find out how much graywater is produced in homes every day. They graph their results and discuss energy efficiency implications. Students are then challenged to find ways to reduce water use within the home.

Multiply the perimeter of a smaller polygon by the scale factor to determine if polygons are similar in this video tutorial. [2:16] Assess learning with a quiz.

Students learn about contact stress and its applications in engineering. They are introduced to the concept of heavy loads, such as buildings, elephants, people and traffic, and learn how those heavy loads apply contact stress. Through the analysis of their own footprints, students determine their contact stress.

When you are asked to make an object bigger or smaller, you will ask, "by how much?". In this case, scale factor can help answer the question. In this lesson, we will practice how to enlarge and reduce objects according to the scale factors given to us. A video tutorial is provided.

Maps are designed to allow people to travel to a new location without a guide to show the way. They tell us information about areas to which we may or may not have ever been. There are many types of maps available for both recreational and professional use. A navigator uses a nautical map, while an engineer might use a surveyor's map. Maps are created by cartographers, and they can be very specific or very general, depending on their intended use. The focus of this lesson is on how to read and use topographical maps. Students will also learn to identify the common features of a map. Through the associated activities, students will learn how to use a compass to find bearing to an object on a map and in the classroom.

Students overlay USGS topographic maps into Google Earth’s satellite imagery. By analyzing Denali, a mountain in Alaska, they discover how to use map scales as ratios to navigate maps, and use rates to make sense of contour lines and elevation changes in an integrated GIS software program. Students also problem solve to find potential pathways up a mountain by calculating gradients.

Take a journey inside a leaf of a redwood tree! Enter the stoma and view the inside of a plant cell, translucent enough to capture light from the sun. Fly by familiar structures like the nucleus and mitochondria, and settle into the chloroplast to watch photosynthesis at work. [3:00] The video is followed by three different classroom ideas.

Start with the questions all students ask: How big is the universe, how far away are the planets and stars, how did they form and when, how do they move and why? Build on their natural curiosity. The Smithsonian, in cooperation with NASA, brings you lesson plans to help students discover answers and questions that can't be answered!

Two figures that are the same shape and have the same angle measurements are similar figures. Learn all about them in this tutorial. [7:22]

Scale is used to represent the relationship between a measurement on a model and the corresponding measurement on the actual object. View this tutorial and learn about scale factor. [4:20]