All of the answer choices are examples of mixtures. Smoke is a mixture of ash and air, trail mix is a mixture of all of the different ingredients (raisins, peanuts, chocolate chips, etc.), and a closet of clothes is a mixture of varying clothing types (pants, dresses, skirts, shirts, hats, etc.). All of these answer choices have at least two substances that are mixed to form something new.

The students in the class created a new substance when they mixed the water and pepper, but the change is only physical. The pepper can be separated from the water, and there is no permanent change to either substance. There was no change in smell or color, and no new substance was formed as in a chemical change.

Separating a mixture is a way to reverse the creating of something new. If sand and rocks were mixed, a mixture was made with the two substances. It can be changed, and the mixture separated if the stones and sand are sifted. The small grains of sand will fall through the sifter leaving the rocks on top and separated.

Iron has a higher density than rubber, meaning that it's weight or mass will be greater even if it's the same size. Standard units are used to measure and describe physical quantities such as weight, time, temperature, and volume.

The answer is "-30 degrees Fahrenheit"

Standard units are used to measure and describe physical quantities such as weight, time, temperature, and volume. The standard unit for temperature is degrees Fahrenheit. Volume is measured in Liters, weight in pounds, and time is measured in minutes, seconds, or hours.

The answer is liquid number 2. Density is a measure of the amount of "stuff" in a given volume. More dense objects sink and less dense objects float.

The answer is 45 because there are 10 millimeters in a centimeter and the ruler is measuring 4.5 centimeters.

The answer is "at number 3" because you measure volume at the meniscus.

This data table provides observations and measurements of two mystery samples. Properties of materials can be used to determine what objects are or the qualities of them. In this case, we are looking for the property that would allude to these samples being solids instead of liquids, and that property is the shape of the samples. Liquids or solids can be measured for mass and volume and described by color, but cannot be characterized by shape. Liquids take the form of the container that they are in, whereas solids maintain a specific shape. These samples are solids because they are a cube and pyramid.

This data table lists what each student observed when they were looking at their material. Some of the properties that describe this material can be gathered through observation, while others are through measurement. In this case, what type of matter the student is looking at comes down to the shape. A gas, liquid, or solid can be any color, mass, or volume, so those characteristics are less helpful in identifying what these materials are. Gases have no shape, liquids take the form of the containers they are in, and solids have a definite figure. Mildred and Dolly look at solids because the material is described as a pyramid and a sphere, which are definite shapes. Edmund and Betsy look at materials with no shape, which means they are gas or liquid, so the only answer choice that matches is "Betsy observed a liquid.".