Show Activity Developed by the University of Colorado Museum of Natural History Description/Learning goals: Participants will sort and classify objects based on size and weight. Participants will practice using scientific tools to measure and make predictions. Supplies:
Activity Instructions:
Science Concepts:Density: Density is found by how much mass (amount of matter) is in a set amount of volume or space. If there is a lot of mass in a small amount of space, the object is very dense. So, if you have two objects of the same volume- like two round balls, but one is more dense than the other, that ball will be heavier. Floating Objects: To have an object float in water, it must be less dense than the water it is sitting in. Remember density isn’t necessarily tied to weight- a large log can float in water while a tiny piece of sand will sink- because the log is less dense than the water. Early Learning 101: Classify, compare, and contrast objects, events, and experiences Have your child compare objects throughout your house based off of size. Can you find multiple objects of a certain shape and size? Like round, and fits in the palm of your hand. Which do they think will be heavier? Follow Up: Talk with your child about the objects around the house they found that were the heaviest. Do they think that any of these object will float in water? Experiment with objects around the house to see if you can find objects of less density than water. One fun way to test this is to get an orange or clementine and see if it floats while unpeeled. Then peel the orange and try again. Because of the porous skin of the orange, air is allowed to be trapped, helping the unpeeled orange to float. Book Suggestion: Things that Float and Things that Don’t by David Adler Are you loving this? Not loving this? Please consider taking a moment to share your feedback with us. Thanks!
Students will observe a copper and an aluminum cube of the same volume placed on a balance. They will see that the copper has a greater mass. Students will try to develop an explanation, on the molecular level, for how this can be. Students are then given cubes of different materials that all have the same volume. Students determine the density of each cube and identify the substance the cube is made from. ObjectiveStudents will be able to calculate the density of different cubes and use these values to identify the substance each cube is made of. Students will be able to explain that the size, mass, and arrangement of the atoms or molecules of a substance determines its density. EvaluationDownload the student activity sheet, and distribute one per student when specified in the activity. The activity sheet will serve as the “Evaluate” component of each 5-E lesson plan. SafetyMake sure you and your students wear properly fitting goggles. Materials for Each Group
Materials for the Demonstration
Notes about the materialsCubesFor this lesson, you will need a set of cubes of different materials that are all the same volume. These sets of cubes are available from a variety of suppliers. Flinn Scientific sells a Density Cube Set, Product #AP6058. This set comes with 10 cubes—4 metal, 3 plastic, and 3 wood. It is easier for students if you reduce the number to 8 by using all the samples of metal but only two wood and two plastic cubes. We suggest using the nylon (off-white, least dense) plastic cube and the PVC (gray, most dense) plastic cube. For the wood, we suggest using the oak (darker and most dense) and either the pine or poplar (paler, less dense). In the activity, each group will need to measure the mass of each of the eight cubes. Groups will need to measure and record their data for a cube and pass it along to another group until each group has used each of the cubes. BalancesUse a simple, plastic, two-sided balance that looks like a see-saw for the demonstration. One of the least expensive is Delta Education Primary Balance (21-inch) Product #WW020-0452. Have students use any balance that can measure in grams. Metric rulerStudents will use a metric ruler in the engage portion of the activity when they measure the length, width, and height of a cube along with you. About this LessonThis is the first lesson in which students see models of molecules that are more complex than a water molecule. Some of these molecules may look a little intimidating. Let students know that they do not need to memorize or draw these molecules. For the purpose of this chapter, students only need to think about the size and mass of the atoms that make up the molecule and how they are arranged in the substance.
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