Science: Atoms & Molecules Unit

This unit could be easily adapted to a variety of units and/or lessons. This unit is titled Atoms & Molecules in the state of New Mexico, and in my district, where each classroom has access to the units in kits from The Center for Hands on Learning. The great thing about these kits is that the activities and information can be easily reproduced at a very low cost, as they mostly involve household items. This page exists for two purposes. First, many of the links are things I will be using in class, but I also have the teacher in mind who does not have access to materials and need high quality things to do in class. On this page, I will focus mainly on providing important, immediately usable links to information, activities, videos, and printable documents (mainly in pdf format). The following major concepts are taught during this unit, and it can normally be completed in 8-12 forty-five minute sessions.

  • Atoms & Molecules
  • States of Matter
  • Mass of Objects
  • Volume of Solids
  • Density
Provided below are various links to each important concept (TEACHER RESOURCES ARE LISTED LAST AND ARE IN ALL CAPS):

Atoms & Molecules

  • AN ATOM APART: A pdf document with a one page reading, questions, and a crossword. The reading is good in that it provides the basic information about atoms.
  • MOLECULARIUM: A fantastic teachers guide with multiple great, low cost classroom activities and labs, as well as great visuals and information. I especially like the activities on page 11, 15, and the vocabulary list on pages 26-27.
  • ATOMS AND MOLECULES UNIT: This unit provides many of the activities that I do in my classroom, including growing salt crystals and working with different materials to build models.
  • PRINTABLE PERIODIC TABLES: Here is one in color, and one in black and white.
  • FUN WITH ATOMS AND MOLECULES: A 2 page pdf that outlines a very simple yet effective activity for students to try in class. This has students play the part of the nucleus, protons, neutrons, etc, to visualize the movement within an atom. 
  • ATOMIC MODELS: A 2 page pdf that shows the structure of atoms.
  • INVESTIGATING MATTER THROUGH INQUIRY: A huge 474 page document provided by the American Chemical Society that has pretty much any activity you can imagine. I'll be consulting this document probably as much as I do my own curriculum and teachers guide, there is SO MUCH in here, it's the definitive stop for activities on atoms and molecules. This document is not mine, but I am providing a link to this from my Google Drive for convenience.

States of Matter

Mass of Objects, Volume of Solids, and Density

I used to teach mass by having students build balance scales, and measure the mass of different objects using gram cubes. It's important for students to conceptually understand the difference between mass and weight, so that's a good place to start. The following links are good to use in the classroom to help with teaching this important scientific concept.
  • Float or Sink, You Find Out!: This is a simple online activity in which you find the volume and mass of an object, and then see if it will float. It shows simply the concept of density, in that if the volume of an object (in milliliters) is greater than its mass (in grams), the object will float because it will have a density (mass divided by volume) less than that of water. This also helps students find volume using water displacement, which is how I teach this in science class. 
    • The Float or Sink, You Find Out! activity has an accompanying pdf worksheet, that is worthwhile in having students fill out. I will be using this as a precursor to the mass, volume, and density labs that we will conduct in class.
  • MAINTAINING THE BALANCE: A quick balancing activity where students find out the mass of an object in paper clips. A nice pdf worksheet.
  • FLOATING AND SINKING: A pdf packet with activities about density using the displacement method. Good stuff!
I'm going to end this page by explaining how I do each of the lab activities included in this unit. A couple of fun science activities I do are more for the "wow factor," but everything fits within the content of the unit. Then, finally, at the tail end of this page, you will find links to the videos I use in this unit. 
  • VOLUME: 
    • VOLUME OF REGULAR SOLIDS: I teach my students how to find the volume of regular solids using the simple formula of Volume = Length x Width x Height. (v= l x w x h). It's easiest for a fourth or fifth grader to understand that the unit is cubed because there are three dimensions being measured, which is why it's called "3 dimensional." For non-regular solids, like a rock or a nail, that can't be measured using a mathematical formula (at least not in elementary school), we use the displacement method.
    • DISPLACEMENT METHOD: If an object is non-regular, like a rock, nail, or any other object that you can't apply the formula for volume to, the displacement method is best. Using a graduated cylinder, have students fill up to a "zero point," a point where the entire object will be submerged when you place it in the water. Then, after you put the object in the water, measure how much the water went up. The final point of the water minus the starting "zero point," will give you the volume of that object. It's common to use Milliliters (ml) to measure this.
  • MASS OF OBJECTS:
    • We find the mass of objects in class using a balance scale. Real quick, here's a worksheet that asks students to practice interpreting the data within scales. A very simple, yet good lead in activity. DOWNLOAD HERE (pdf). In past years I've had students make their own balance scales out of materials that were purchased through the science kit company that the schools contract with. There are a few low cost ways of doing this. This first method, using yogurt containers and clothes hangers is really good. What I do is start asking parents to help collect materials and I usually end up with more than enough. 
    • Once the scales are built, you can measure using anything, paper clips, crayons, etc., as long as you know how much one of each weighs. If you have access to gram cubes, I highly recommend using those. 
  • DENSITY: 
    • The actual method for finding out the density of an object is using the formula density = mass / volume ( d = m / v). It's a simple method, but sometimes students are still left with some confusion. Water has a density of 1 g/cc, which ends up being something of a baseline for the measurements of mass in grams and volume in milliliters. Anything with a density over 1 g/ml will sink in water, anything with less will float. So what exactly is density? I have students practice playing with the concept by measuring the mass, volume, and density of various objects, and testing out their results by seeing if they float or sink in water. The best method for getting this through is discussion, practice, and repetitions with the math.
    • DENSITY OF GASES: Here's a site that has visuals showing the molecular movement inside of different gases. I blow up a regular party balloon with air from my lungs, then, next, I fill another balloon up with 2 tablespoons of baking soda. Take a glass soda bottle, fill it with 1/2 cup of vinegar. Secure the balloon over the top of the soda bottle, and let the baking soda fall into the vinegar. The chemical reaction will create carbon dioxide, which will be caught in the balloon. Let this happen until the balloon gets plenty of carbon dioxide in it, work with it to make sure no liquid gets in the balloon. Remove, make the same size as the air balloon, and tie off. Now, you'll have an air balloon and a carbon dioxide balloon. Although both have the same volume, they will have a different mass, and a different density. Students can play with the balloons and see that the carbon dioxide balloon feels different, falls faster, and is obviously heavier than the air balloon. This is a great, visual activity to prove that not all gases are created equal. 
  • GROWING SALT CRYSTALS: 
    • A final project for this unit is usually growing salt crystals. There are endless variations on this, but I usually gives students the option of using epsom salt, kosher salt, borax, alum, a salt and vinegar solution, and finally, everyone gets to rust a paperclip in a copper sulfate solution. It's a simple activity, here are the instructions:
      • Each student receives 2 tablespoons of their chosen mixture in a styrafoam cup. Each student is then given approximately one third of the cup full of boiling hot water. Using a stirring stick, they stir their solution until it is completely dissolved. Students then take a popsicle stick, wrap string around it, and tie either a washer or a pipe cleaner snowflake to the end. I have them leave them alone for about a week, then they have their crystals, that we can analyze under microscopes.
      • For the copper sulfate solution, I mix two cups of boiling water with three tablespoons of copper sulfate. Each student gets some sort of lid full of the solution. They then drop a paperclip into the solution. It's neat to see the paperclips rust on contact. Within a week, the paperclips will mostly dissolve, turning the solution a rust color. 
  • 2 END OF UNIT "BANG UP" ACTIVITIES:
    • Every student likes a showy activity. These two are always favorites.
      • LIGHT IN THE DARKNES: Cut up a medium sized potato into irregular sized chunks (2x2 inches on average). Put them inside of a sealable rubbermaid container. Pour in enough isopropyl alcohol (100% would be great) to completely submerge the potato chunks. Seal up the container for about 15 minutes, you can give the container a quick shake to get things going. You can discuss that the chemical reaction of the alcohol and the starch in the potato creates an oxygen rich environment inside the bottle. Take a kebab skewer and light it on fire. Keep the tip burning, and let the fire go out. What you want is an ember on the end of the stick. Now, have someone turn off the lights. Open up the container, and put in the ember burning stick. The whole container should light up, burning off the oxygen. It's a seriously cool activity that kids love. It's not the basis of anything that I teach, but is a neat activity that everyone enjoys.
      • WHOOSH BOTTLE: To do the whoose bottle, you need ethanol (you can buy denatured alcohol at most stores, like Wal Mart or a hardware store). You will also need a 5 gallon water jug (the big ones that they sell water in, they're pretty easy to get at a grocery store or hardware store). Put 1 tablespoon of the denatured alcohol inside the water jug, and move it around until it evaporates. If you're especially adventurous bring a hair dryer and use it to heat the jug and evaporate the alcohol. Now, here's the fun part. You can sit the jug upright and drop a match in (watch your fingers, and don't let the kids do this part). OR, you can lay the jug on its side and do this, and watch it fly across the room. It's a cool activity that shows the power of expanding gas. Steve Spangler has done this activity as well, check out his version (it's not as powerful if you don't use a hair dryer).


Finally, here are the videos that I use to teach this unit: 

On the first day of this unit, I show this video. It's also a great lead in for the unit on Earth & Space Science, so you'll see it again in that unit. It's Cosmic Voyage, an IMAX presentation, narrated by Morgan Freeman. It gives insight into the immensity of space, and then the smallness of the world of atoms and molecules:

I always show this Bill Nye episode fairly early in the unit as well. His videos are great:

Bill Nye - Atoms (part 1)


Bill Nye - Atoms (part 2)




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