Typically in chemistry we cannot directly observe what is happening because it is occurring on a microscopic level. In order to better understand the cause of our macroscopic observations, we will need to examine microscopic particle behavior and create models to represent what we cannot see.

You will observe food coloring added to both hot and cold water.

In the question below you will be asked to make a prediction about the speed of the spread of the food coloring in both temperatures of water. 

Three trials of the experiment are shown below, view each one separately. You will be recording both qualitative and quantitative measurements for each trial below the videos.

Trial 1

Trial 2

Trial 3

In chemistry class, when we answer a question, we call that answer a "claim". You may have heard this term before, in relation to the explanation structure Claim-Evidence-Reasoning. A claim states the relationship between your independent variable and your dependent variable. You do not provide any data or explanation of why this relationship exists. 

Evidence is data that we gather in class, organized to support a claim. It is important that you realize that the data you record from an experiment in class is not automatically evidence. To produce evidence, you will pull two data points from your raw data to support the relationship stated in your claim. For a lab report, you will be required to compose evidence with multiple data point sets. Quantitative data is prioritized over qualitative data if available.

Reasoning is the explanation of why the data is appropriate (i.e., why is this data relevant?) and how the data support the claim. This is where you explain the science behind why your evidence supports your claim.

You already made a claim to answer the question: "In which temperature water did the food coloring spread faster?" on the previous page. It was clear in the experimental video that the food coloring spread faster in hot water. Below, you will be asked to support that claim with evidence and to explain why your evidence supports that claim with reasoning.

If we were to write a claim evidence reasoning statement to answer the question "In which temperature water did the food coloring spread faster?", it would look something like this: 

Claim: The food coloring spread faster in hot water than it did in cold water.

Evidence: In hot water, food coloring took X seconds to hit the walls of the container. In cold water, food coloring took X seconds to hit the walls of the container.

Reasoning: Hot particles move faster than cold particles. As temperature increases, so does the speed of particle movement.

The following image shows food coloring particles in hot water vs cold water, according to how we will model things in our class. Examine the model and answer the questions below.