Comparing Solutions
Aligned to 3-5-ETS1-2 — Next Generation Science Standards.
What this lesson teaches
A problem can be solved in more than one way. Engineers think up several possible solutions, then compare how well each one meets the criteria and fits within the constraints before choosing the best.
Worked examples
Example 1
To carry your books, you could design a bag, a cart, or a strap. Comparing them, the cart holds the most but won't fit through a narrow doorway — so the bag might win.
Example 2
Three ways to cross a stream: stepping stones, a plank, a rope. The plank is fastest to build but the stones last through a flood.
Example 3
No solution wins on every criterion. Write down which criteria matter most before you choose, so the decision is honest.
Practice questions
- Think of two different ways to solve the same problem. How are they different?
- List three ideas for keeping a drink cold, then rank them from best to worst.
- Explain how you would decide which of two solutions is the better choice.
Watch the lesson
Every lesson comes with a video taught in English and Spanish — the same video the QR code in the printed workbook opens.
▶ Watch this lessonEn español
Comparar soluciones
Un problema puede resolverse de más de una manera. Los ingenieros piensan en varias soluciones posibles y luego comparan qué tan bien cumple cada una con los criterios y las restricciones antes de elegir la mejor.
Ejemplo 1: Para cargar tus libros, podrías diseñar una mochila, un carrito o una correa. Al compararlos, el carrito carga más pero no pasa por una puerta angosta — así que la mochila podría ganar.
Ejemplo 2: Tres formas de cruzar un arroyo: piedras, una tabla, una cuerda. La tabla es la más rápida de construir pero las piedras aguantan una crecida.
Ejemplo 3: Ninguna solución gana en todos los criterios. Anota cuáles criterios importan más antes de elegir, para que la decisión sea honesta.
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