Texas Instruments
Texas Instruments: Triangle Inequality Theorem
In this activity, students will explore the concepts underlying the Triangle Inequality Theorem by comparing side lengths and angle measures of a triangle. They will use an interactive construction to see why this theorem is true.
Science Education Resource Center at Carleton College
Serc: Bending Light
In this physics lab students will observe light bending as it enters a medium. Students will then be able to calculate the angle of the bent light and compare that with other students observations for like and different mediums.
Science Education Resource Center at Carleton College
Serc: Calculating the Declination of the Sun for Elementary Students
In the school courtyard, students will measure the apparent path of the sun across the sky using a toilet plunger. Students will then generate questions as to why the sun appears to move, and what is really happening in the process. We...
PBS
Pbs Learning Media: Farmers in Peril
In this video from Wide Angle, the sparse life of the rural farmer in India is compared to the wealth of consumer goods available to wealthier city dwellers.
Wolfram Research
Wolfram Math World: Similar Triangles
Find the necessary information to decide if triangles are similar at this MathWorld site.
CK-12 Foundation
Ck 12: Math Grade 4
Browse resources related to fourth-grade math standards. Click on a topic for interactive lessons, videos, and extra practice.
BBC
Bbc: Gcse Bitesize: Why Do Scientists Think That Light and Sound Are Waves?
Light travels as transverse waves and can travel through a vacuum. Sound travels as longitudinal waves and needs to travel through a solid, liquid or gas. Read about the properties of light and of sound, and learn the differences between...