Question

1. a student kept a notebook during an investigation. which recorded observation was likely a physical change?

a solid formed when two liquids were mixed together.
the solution was heated for two minutes until it boiled.
two solutions were mixed and the resulting solution felt hot.
the color of two mixed solutions changed from clear to white.

Explanation:

An observation in a science - related investigation is a description of what is seen, felt, etc. during an experiment. A color change (the color of two mixed solutions changed from clear to white) is a direct visual observation. Feeling hot is also a sensory observation. Heating a solution until it boils is an action, not an observation. Forming a solid when two liquids are mixed is an inference about a chemical reaction that has occurred based on the result, not just a simple observation.

Answer:

The color of two mixed solutions changed from clear to white., Two solutions were mixed and the resulting solution felt hot.