How the heck do you teach the conservation of mass to 8th grade students?  Lab activities are always good, but what lab activity can be done without the students getting super confused?  Two components are required. First, a chemical reaction is needed.  It must use simple chemicals, and it should be obvious that a chemical reaction took place.  Second, it must be easily quantifiable. In other words the mass is easy to measure and it must show very clearly that mass was not lost during the chemical reaction.  I think I may have finally developed a lab activity that addresses both components.  Watch the video and download the student worksheet for more details.

Evolution is the change in a species over time. Scientists look at multiple sources for evidence that a species has evolved overtime.  Fossils are one of those sources.  How do scientists no the age of a fossil? They use a technique called radiometric dating to determine the absolute age of a fossil.  You can use M & M"s to simulate how radioactive decay actually works.  Watch the video to see how and download the student handout (word document).

Let’s Grub on Some Grass Beetles is a natural selection simulation. Natural selection is the “process by which favorable heritable traits become more common in successive generations of a population of reproducing organisms, and unfavorable heritable traits become less common.” In this activity, part 1 involves variations in silver beak loon beak types. There are tweezers, spoon, and knife shaped beaks. The beak best adapted to capturing grass beetles will survive and more chances to reproduce. The tweezers and spoon beaks are best adapted. The population of silver beak loons will change to a majority of tweezers and spoon beaks. Part 2 deals with variations in grass beetle color. The green grass beetles are best adapted to hiding in the grass than the orange or yellow grass beetles. In successive generations the populations of grass beetles will shift to green colors, since they will have the best chance to survive, reproduce and pass the variation to their offspring.

Watch the video and listen to the commentary on how to do the activity. Download handout: Let’s Grub on Some Grass Beetles

Protein synthesis is the process that the cell goes through to make a protein from the information stored in the DNA. The video below shows a demonstration that you can do in your classroom to show how protein synthesis works. This demonstration emphasizes the following points:

1. DNA contains the information to make a specific protein.
2. The DNA is in the nucleus of the cell.
3. The DNA cannot leave the nucleus.
4. The ribosomes make the protein from the information.
5. The ribosomes are in the cytoplasm and cannot go into the nucleus.

The metaphor that I use in class is that the DNA is like a series of recipe books in the library. These books cannot be checked out/taken out of the library. The only way to get the information that is in the books out of the library is to make a copy. mRNA is the copy of the information that can leave the nucleus and go into the cytoplasm so that the ribosome can read and make the protein. Watch the video to see how it comes all together.

Teaching tips: Place the amino acids around the classroom (cytoplasm). Assign students to be specific tRNA’s. They will get the specific amino acid and bring it to the ribosome for you.



An important component in learning matter, is being able to measure how much space matter takes up–in other words volume. Measuring the volume of liquids requires the use of a graduated cylinder. Students need practice to use the graduated cylinder effectively. My colleague, Cindy Giove, shared the lab activity, Rainbow Volume with me. It is a fun way for students to practice and an easy way for teachers to assess their growth. Students first start out with beakers of blue, red, and yellow water. They then measure a certain amount of colored water into each test tube. If they follow the directions carefully, and do the measurements accurately they will end up with test tubes with 11 ml of red, orange, yellow, green, blue, and purple water. Download rainbow volume handout. Download rainbow volume key.

Materials: beakers of red, blue, and yellow water, and a 25 ml graduated cylinder

Materials: empty test tubes at the beginning

End results: colors and equal volumes