Density is a measure of how much matter (mass) there is in a given amount of space (volume). Density basically describes how tightly packed the tiny particles that make up any substance/material are. The higher the density, the more closely packed the particles (called atoms and molecules) are. The lower the density, the more spaced out the particles are.
If the same piece of clay is shaped into two different shapes (oval and hollow square), then does its density change? In order to answer this question, we simply need to measure the mass and volume of the clay at each shape.
Dr. OPHERC holds two different amounts of molasses that came from the same jar. Does the amount of molasses affect its density?
Again, in order to answer this question, we simply need to measure the mass and volume of the molasses at each amount.
If we heat or chill the same amount of water, then does the density of the water change? Fairly measuring the mass and volume of the water (in order to address this question) is a bit more challenging, because water evaporates when heated, thus affecting both the mass and the volume of water being measured.
Check out the video below on "lake stratification" in order to learn more about how temperature affects the density of water (and other materials).
Matter generally compresses (packs up/tightens up) at cooler temperatures, and spreads out at warmer temperatures. This is very similar to the behavior of penguins. During the brutally cold winter, penguins huddle (compress). But during the warmer seasons, penguins spread out.
Therefore, temperature does affect density. The relationship between temperature and density explains how hot air balloons work, why we run a hard-to-open jar under hot water, and why the bottom layers of a lake are much cooler than the top layers!
Complete the assignment on Google Classroom.