Question

a lightweight material is being tested for effectiveness in blocking ultraviolet (uv) rays from the sun that cause skin to burn and possibly develop skin cancer. which method would be most helpful for testing this material? use specialized equipment to measure how much uv light passes through stacks of one, five, or 20 layers of the material. test the material in controlled natural settings by using natural uv light, and measure the uv light that passes through. write a survey that asks people on beaches about their preferences for sunscreen and protective materials. test the material in a lab setting by using humans and a variety of uv light sources, and develop a scale to measure the damage that is caused to human skin.

Explanation:

Step1: Identify the goal

The goal is to test the effectiveness of a lightweight material in blocking UV rays.

Step2: Analyze each option

Using specialized equipment to measure UV - light transmission through layers of material directly measures the material's ability to block UV rays which is relevant to the test. Testing in natural settings with natural UV light has too many uncontrolled variables. Testing in a lab with humans exposes humans to unnecessary UV risk and has ethical concerns. Writing a survey about preferences is not related to testing the material's UV - blocking ability.

Answer:

Use specialized equipment to measure how much UV light passes through stacks of one, five, or 20 layers of the material.