Students are introduced to the important concept of density with a focus is on the more easily understood densities of solids. Students use different methods to determine the densities of solid objects, including water displacement to determine volumes of irregularly-shaped objects. By comparing densities of various solids to the density of water, and by considering the behavior of different solids when placed in water, students conclude that ordinarily, objects with densities greater than water sink, while those with densities less than water float. Then they explore the principle of buoyancy, and through further experimentation arrive at Archimedes' principle that a floating object displaces a mass of water equal to its own mass. Students may be surprised to discover that a floating object displaces more water than a sinking object of the same volume.

This lesson focuses on how food packages are designed and made. Students will learn three of the main functions of a food package. They will learn what is necessary of the design and materials of a package to keep food clean, protect or aid in the physical and chemical changes that can take place in a food, and identify a food appealingly. Then, in the associated activity, the students will have the opportunity to become packaging engineers by designing and building their own food package for a particular type of food.

In the first of two lessons of this curricular unit, students are introduced to the concept of friction as a force that impedes motion when two surfaces are in contact. Student teams use spring scales to drag objects, such as a ceramic coffee cup, along a table top or the floor, measuring the frictional force that exists between the moving object and the surface it slides on. By modifying the bottom surface of the object, students find out what kinds of surfaces generate more or less friction. They also discover that both static and kinetic friction are involved when an object initially at rest is caused to slide across a surface. In the second lesson of the unit, students design and conduct experiments to determine the effects of weight and surface area on friction. They discover that weight affects normal friction (the friction that results from surface roughness), but for very smooth surfaces, the friction due to molecular attraction is affected by contact area.

In this lesson, students will learn that minerals are a necessary part of our diet. They will learn that different minerals have different functions in the body. More specifically, they will discover that iron is necessary to carry oxygen around the body. In the associated activity, students will design a process that removes the most iron from the cereal.

Students visit second- and fourth-grade classes to measure the heights of older students using large building blocks as a non-standard unit of measure. They also measure adults in the school community. Results are displayed in age-appropriate bar graphs (paper cut-outs of miniature building blocks glued on paper to form bar graphs) enabling a comparison of the heights of different age groups. The activities that comprise this activity help students develop the concepts and vocabulary to describe, in a non-ambiguous way, how heights change as children age. This introduction to graphing provides an important foundation for creating and interpreting graphs in future years.

The marine environment is unique and requires technologies that can use sound to gather information since there is little light underwater. The sea-floor is characterized using underwater sound and acoustical systems. Current technological innovations are allowing scientists to further understand and apply information about animal locations and habitat. Remote sensing and exploration with underwater vehicles allows scientists to map and understand the sea floor, and in some cases, the water column. In this lesson, the students will be shown benthic habitat images produced by GIS. These imaged will lead to a class discussion on why habitat mapping is useful and how current technology works to make bathymetry mapping possible. The teacher will then ask inquiry-based questions to have students brainstorm about the importance of bathymetry mapping.

Students discover the scientific basis for the use of inclined planes. Using a spring scale, a bag of rocks and an inclined plane, student groups explore how dragging objects up a slope is easier than lifting them straight up into the air. Also, students are introduced to the scientific method and basic principles of experimentation. To conclude, students imagine and design their own uses for inclined planes.

Students apply the concepts of conduction, convection and radiation as they work in teams to solve two challenges. One problem requires that they maintain the warm temperature of one soda can filled with water at approximately human body temperature, and the other problem is to cause an identical soda can of warm water to cool as much as possible during the same 30-minute time period. Students design their engineering solutions using only common everyday materials, and test their devices by recording the water temperatures in their two soda cans every five minutes.

Students conduct experiments to determine what environmental factors favor decomposition by soil microbes. They use chunks of carrots for the materials to be decomposed, and their experiments are carried out in plastic bags filled with dirt. Every few days students remove the carrots from the dirt and weigh them. Depending on the experimental conditions, after a few weeks most of the carrots have decomposed completely.

In this lesson and its associated activity, students conduct a simple test to determine how many drops of each of three liquids can be placed on a penny before spilling over. The three liquids are water, rubbing alcohol, and vegetable oil; because of their different surface tensions, more water can be piled on top of a penny than either of the other two liquids. However, this is not the main point of the activity. Instead, students are asked to come up with an explanation for their observations about the different amounts of liquids a penny can hold. In other words, they are asked to make hypotheses that explain their observations, and because middle school students are not likely to have prior knowledge of the property of surface tension, their hypotheses are not likely to include this idea. Then they are asked to come up with ways to test their hypotheses, although they do not need to actually test their hypotheses. The important points for students to realize are that 1) the tests they devise must fit their hypotheses, and 2) the hypotheses they come up with must be testable in order to be useful.

Most of the flavoring in gum is due to the sugar or other sweetener it contains. As gum is chewed, the sugar dissolves and is swallowed. After a piece of gum loses its flavor, it can be left to dry at room temperature and then the difference between its initial (unchewed) mass and its chewed mass can be used to calculate the percentage of sugar in the gum. This demonstration experiment is used to generate new questions about gums and their ingredients, and students can then design and execute new experiments based on their own questions.

Kindergartners measure each other's height using large building blocks, then visit a 2nd and a 4th grade class to measure those students. They can also measure adults in the school community. Results are displayed in age-appropriate bar graphs (paper cut-outs of miniature building blocks glued on paper to form a bar graph) comparing the different age groups. The activities that comprise this lesson help students develop the concepts and vocabulary to describe, in a non-ambiguous way, how height changes as children get older. The introduction to graphing provides an important foundation for both creating and interpreting graphs in future years.

Students set up and run the experiments they designed in the Population Growth in Yeasts associated lesson, using simple yeast-molasses cultures in test tubes. Population growth is indicated by the amount of respiration occurring in the cultures, which in turn is indicated by the growth of carbon dioxide bubbles trapped within the culture tubes. Using this method, students test for a variety of environmental influences, such as temperature, food supply and pH.

Students are introduced to the concept of inertia and its application to a world without the force of friction acting on moving objects. When an object is in motion, friction tends to be the force that acts on this object to slow it down and eventually come to a stop. By severely limiting friction through the use of the hover pucks, students learn that the energy of one moving puck is transferred directly to another puck at rest when they collide. Students learn the concept of the conservation of energy via a "collision," and will realize that with friction, energy is converted primarily to heat to slow and stop an object in motion. In the associated activity, "The Puck Stops Here," students will investigate the frictional force of an object when different materials are placed between the object and the ground. This understanding will be used to design a new hockey puck for the National Hockey League.

Students are introduced to the concept of simple tools and how they can make difficult or impossible tasks easier. They begin by investigating the properties of inclined planes and how implementing them can reduce the force necessary to lift objects off the ground.

Students experience a simulation of echolation, using the sensory method to walk along a path while blindfolded. This relates to the issue of bycatching by fisheries, which they learned about in the associated lesson. Bycatching affects marine animals, especially dolphins, which use echolocation to identify the location of objects in the water, but have difficulty identifying nets, and thus are often caught accidentally. Students learn how echolocation works, why certain animals use it to determine the size, shape and distance of objects, and how humans can potentially take advantage of dolphins' echolocation ability when developing bycatch avoidance methods.

Students plant sunflower seeds in plastic cups, and once germinated, expose them to varying light or soil moisture conditions. They measure growth of the seedlings every few days using non-standard measurement (inch cubes). After a few weeks, they compare the growth of plants exposed to the different conditions and make bar comparative graphs, which they analyze to draw conclusions about the needs of plants.

Students are introduced to circuits through a teacher demonstration using a set of Christmas lights. Then students groups build simple circuits using batteries, wires and light bulbs. They examine how electricity is conducted through a light bulb using a battery as a power source. Students also observe the differences between series and parallel circuits by building each type.

Why does the Moon not always look the same to us? Sometimes it is a big, bright, circle, but, other times, it is only a tiny sliver, if we can see it at all. The different shapes and sizes of the slivers of the Moon are referred to as its phases, and they change periodically over the course of a lunar month, which is twenty-eight days long. The phases are caused by the relative positions of the Earth, Sun, and Moon at different times during the month.

Students work in teams of two to discover the relative positions of the Earth, Sun and Moon that produce the different phases of the Moon. Groups are each given a Styrofoam ball that they attach to a pencil so that it looks like a lollipop. In this acting-out model exercise, this ball on a stick represents the Moon, the students represent the Earth and a hanging lightbulb serves as the Sun. Students move the "Moon" around them to discover the different phases. They fill in the position of the Moon and its corresponding phase in a worksheet.