Lesson Plan
To Float or Not to Float - A Lesson on Density by ECSDM
Subject
Math, Science & Technology, Science (NYS P-12)
Grade Levels
Intermediate, 7th Grade, 8th Grade
Description
This lesson discusses density as a property of matter. Students will use the formula to calculate density to determine if an object/material will sink or float.
Website(s)
Brain Pop
United Streaming
Materials and Resources
Density Activity Sheet.doc
To Sink or To Float-Finding Density.doc
Density lesson organizer.notebook
Density lesson organizer.pdf
Duration
Two 45-minute periods
Learning Objectives
Students will learn:
- To explain and define density.
- To calculate density.
- To explain how to use density to identify a substance.
Materials
- Ice Cubes
- Several blocks of wood and metal (or other materials)
- Rulers and Triple Beam Balance
- 2 Clay Balls (the clay should be the same kind and same amount)
- 2 Large Container with Water
- Graduated Cylinder and 40ml of water.
- Internet Access for additional support from Brain Pop and United Streaming. These websites requires a subscription
- SMART Board software, SMART Board, and projector
Provide students with:
- 2 graduated cylinders
- triple beam balance
- cooking oil
- water
Procedure
First Day:
- Present the question: What would you rather carry through a dessert, a pound of feathers or a pound of lead?
- After discussing the students’ answers, point out that a pound of feathers is the same as a pound of lead. The main difference is that a pound of lead is smaller (has less volume) than a pound of feather.
- Review mass (the amount of material/”stuff” an object has) and volume (the amount of space an object takes up).
- Write the formula for finding density on the board.
- Identify the horizontal line in the formula means to divide the number on top by the number on the bottom.
- Try several examples before introducing density.
- Students can practice using the blocks of wood and metal to find density.
- After students practice, explain the concept of density (a measure of how tightly the matter of a substance is packed into a given volume).
- Density can also be used to identify particle substances because the density of a substance does not change regardless of the size or shape of the piece of substance.
- Allow students to work together to complete the Assessment Activity - Density
Second Day:
- Show the class the clay boat and ball. Both objects should be made of the same kind of clay and the amount of clay.
- Invite the students to predict if the clay objects will sink or float.
- Have a large container with water to finish the demonstration.
- After they have discussed their predictions place the objects in the water. Let the students observe and discuss why the clay boat floats while the clay ball sinks.
- Finally explain that by changing the shape of the clay from a ball into a boat the volume of the clay was changed therefore changing the density.
- Students will then find the density of water and cooking oil. They will determine what the density of any object must be for a substance to float or sink when placed in water.
- There is an assessment activity – “To Sink or to Float" in Word format.
Assessment
- Activity Sheet - Density
- Activity Sheet - To Sink or to Float
