Forums

I am working on making my students more aware of real-life applications and why they should be learning this information. I am stuck on mass, volume, and density. Any thoughts and/or activities? I'm stumped on why anyone should care...oops? haha

Hi Mary,
What grade do you teach? There are quite a few resources on density (and mass and volume) in the NSTA Learning Center. I thought you might be interested in this one in particular: Get in the Game with Team Density. As the article's description mentions, 'Density is a central concept in chemistry and physical science from middle school to college.'
Another activity that sounds interesting is this one:Floating Boats.
It is in The Science Teacher journal, so it is probably appropriate for 7 - 10 graders. Let us know what grade level you are interested in; we will help you with some activity ideas.
My Best,
Carolyn

Hi Mary - One interesting idea that came to mind (especially for density) is to pose the question, "Who likes to go fishing?". Then ask them why they should care about density at a local fishing hole. This could lead into an investigation of the densities of water in the solid and liquid forms which would allow the students to determine the differences in density and come up with an explanation of why they should care about density and how it ultimately affects them. I'm assuming you live in a cooler climate. :) Cheers! Kathryn

Well one really real life application that should be mentioned are boats. Ask them if they were to make a boat and were on a budget, would they make a boat out of iron? Wood? Obviously, if something is less dense than the medium its surrounded by, it's going to float. You might also ask them if they think it's easier to float in the ocean as opposed to a pool? One thing that I have them do to figure out density is to have them measure the mass and volume of various objects - some are really easy, like a square block, others are much harder, like an irregular shape rock. Have them troubleshoot how they can calculate the volume of the rock, its mass, and therefore density. Let them try it on their own; usually there's always one group that catches on and knows that they can find the volume through water displacement!

I teach 7th grade in an urban area - most don't fish or boat, although they could understand the concept.

I think it's more about showing the relationship between mass and volume. I use the density triangle to do this. Also a pretty cool and memorable activity is to measure the density of one of the students in your class. You weigh a student in kg, then get their volume by using water displacement. To do this you fill a trash can full of water drill a hole at the side near the top fill the water to the bottom of the hole and have the student slowly submerge themselves. as the water comes out the hole you measure that and use the triangle to get is density.

When I think of those terms I think of airplanes flying through air, density is less as the airplane flies higher, this is part of the lift formula. Or I think about boats floating on water because of the density is much less than the water it displaces.

Hi again, Mary,
I wanted to bring this article to your attention: Science 101 - Do balances and scales determine an object's mass or its weight?. Anything by Dr. Robertson has lots of great information about how to teach the concepts in question. Plus he always has great cartoons and/or graphics to share.
Also, I came across an article on concept maps that used the concepts of density and buoyancy as the vehicle to teach how to use this strategy in a middle school classroom. It is called: Using Concept Maps in the Science Classroom. Perhaps these two articles will be of help in coming up with ways to teach these concepts to your diverse group of 7th graders. It is fun to hear what other middle school teachers are doing in the way of activities to help their students understand these concepts.

Density - some ocean currents flow due to density. I do a lab where students test different balloons filled with different types and temperatures of water to see how the different densities affect them. I fill balloons with hot water, hot salt water, cold water, cold salt water, room temp water and room temp salt water. I have them experiment with the balloons to try and figure out what is in each balloon and why it is floating, sinking, or perhaps starting to rise after it has sat in the room temperature container for a while. Then we learn more about ocean currents and what drives them.

LAVA LAMPS! Great way to illustrate changing densities and convection currents and they model the water cycle to boot. Also, think about how erosion sorts particles by weight and density (why are the rocks in the river bed and the sand is on the beach?) Another colleague mentioned finding the volume of a child by water displacement - very few schools where you can pull that off these days, what a shame. An old episode of Mr. Wizard demonstrated this, but the water was obviously much too cold. I can still see the child's face! Don

Mary wrote, 'I am working on making my students more aware of real-life applications and why they should be learning this information. I am stuck on mass, volume, and density. Any thoughts and/or activities? I'm stumped on why anyone should care...oops? haha'

Hi Mary,

You have a really great question. The activities mentioned in the the forums are great real-life applications. As a high school science teacher, I always appreciate it when my students' middle school teachers take the time to teach them about the basics. While mass, volume, and density seem unimportant, they are the basis for many applied lab techniques we use in high science biology, chemistry, and physics.

Mass, Volume and Density is pretty much EVERYTHING. I spend a lot of time with this in my class and students need to review and address it constantly. They experience it everyday - you can make it easily relevant. Food is my favorite and especially contraband candy. I have a great chocolate lab - I get small pieces of wrapped candy (squarish) - they measure (a skill they need to develop), calculate volume, weigh it, calculate density. I even had them taken an orange, they figure out the volume using displacment, peel the orange, figure out the peel volume by displacement, use this value to calculate the remaining volume. Weigh everything, calculate density. Compare with classmates. Put parameters on it: which would be the best value based on the mass, cost, density etc. Gets them thinking. And oh, you can't eat the experiment until you get all your data collected and you've evaluated and recorded everything. 100% engagement.

I love it! Fruits, chocolate, and what's the other food group? Don

I found a really good website that simulates density by using different objects with the same density, mass or volume. My students predicted what would happen when I dropped the object in the water. The students had a lot of fun exploring the simulation. Website: http://phet.colorado.edu/

Cynthia thanks for sharing that! I don't teach density in the integrated class that I have (they have that later for physics), but for my summer school classes I do, and that's a great idea. I'll have to try it out next summer. Thanks again for the tip. Do you have students bring in their own objects too?

Thank you for your responses! I like the chocolate/fruit and online simulation ones, especially. (I wish I could dunk a kid in water!) You were all very helpful in forming a better picture of "why should we care" for me and my students! Thanks!

This thread reminded me of a cool challenge that was at a mall a few years back. It uses Archimedes principle which is using density, mass and volume. We were given 8 stirring straws (for coffee), 8 small rubber bands (I think they were the one's used for braces) and a 50 cm piece of aluminum foil. The challenge was to see who could make a boat that could hold the most marbles, washers, etc. This could be used in a class room with a container of water in the front and students working in pairs/groups to see who can float the most mass. It is a great way to use mass, volume and density because students can manipulate variables by their designs. Just brainstorming but one could start off with two pieces of clay that have the same mass, keep one is a rectangle and place in water (it sinks), and shape one into a boat and it floats. This could start a discussion about mass but how the change in shape affected the volume, which in turns changes the density. Then this could turn into the challenge above. A post discussion focusing on density (mass and volume by extension) are central in chemistry and physics. To make it more relevant the discussion can extend to weather, currents and climate which is driven by changes or differences in density in both air and water.

Hi Don – in a middle school mind…There are other food groups?! ;-) Hi Loren, Absolutely. In fact, when they are practicing measuring and weighing objects – I don’t provide them anything for the first lesson. I just show them the basics of how to use a scale and let them rummage through their backpacks and purses. They are much more interested in their own stuff and the curiosity of how it much weighs – singly, combination, space it takes etc. It is a great way to engage students and have them practice measuring and calculating and as a teacher, I don’t have to explain relevance…it’s their stuff, so it is already relevant and important. All - great posts. I've enjoyed reading them all!