Inquiry Based Instructional Model
To intertwine scientific knowledge and practices and to empower students to learn through exploration, it is essential for scientific inquiry to be embedded in science education. While there are many types of inquiry-based models, one model that I've grown to appreciate and use is called the FERA Learning Cycle, developed by the National Science Resources Center (NSRC):
A framework for implementation can be found here.
I absolutely love how the Center for Inquiry Science at the Institute for Systems Biology explains that this is "not a locked-step method" but "rather a cyclical process," meaning that some lessons may start off at the focus phase while others may begin at the explore phase.
Finally, an amazing article found at Edudemic.com, How Inquiry-Based Learning Works with STEM, very clearly outlines how inquiry based learning "paves the way for effective learning in science" and supports College and Career Readiness, particularly in the area of STEM career choices.
In this unit, students will develop an understanding of gravity while focusing heavily on the 5th Grade Engineering and Design standards. In the first few lessons students will explore the relationships between gravity, weight, and mass. Then, students will apply their understanding of gravity to engineer and design parachutes and roller coasters.
Summary of Lesson
Today, I will open the lesson by asking students to examine the relationships between a planet's mass, radius, and surface gravity factor (gravity in relation to Earth). Students will then explore how much a pop can weighs on other celestial bodies in the Solar System. Tomorrow, students will construct and analyze a bar graph using their collected investigation data. Through this investigation, students will develop an understanding that gravity is a downward force that pulls objects toward the center of a planet's core.
Next Generation Science Standards
This lesson will address the following NGSS Standard(s): 5-PS2-1. Support an argument that the gravitational force exerted by Earth on objects is directed down.
Scientific & Engineering Practices
For this lesson, students are engaged in Science & Engineering Practices 2 and 5.
Science & Engineering Practice 2: Developing and Using Models - Students weigh pop cans that model the actual weight of a soda at different locations in the Solar System. They use these models to describe a scientific principal: The weight of an object changes on each celestial body as the gravitational pull changes.
Science & Engineering Practice 5: Using Mathematics and Computational Thinking - Students measure the estimated weight of soda cans and they calculate the actual weight of each soda can on different celestial bodies in the Solar System (Mars, Earth's Moon, Sun). After graphing the actual quantities, students analyze the set of data closer.
To relate content across disciplinary content, during this lesson I focus on Crosscutting Concept 1.
Crosscutting Concept 1: Patterns - Through questioning and observing, students will recognize patterns between the weight of a can of soda on various celestial bodies.
Disciplinary Core Ideas
In addition, this lesson also aligns with the Disciplinary Core Idea, PS2.B. Types of Interactions: The gravitational force of Earth acting on an object near Earth’s surface pulls that object toward the planet’s center. (5-PS2-1)
To add depth to student understanding, when I can, I'll often integrate ELA standards with science lessons. Today, students will work on meeting CCSS.ELA-LITERACY.RI.5.2: Determine two or more main ideas of a text and explain how they are supported by key details; summarize the text. In this lesson, students will identify supporting details that support the main idea of the text, "Mass and weight are different."
Students will engage in Math Practice 2: Reason abstractly and quantitatively. As students construct a bar graph using data in decimal form, they will also be conceptualizing decimals and making sense of quantities and their relationships.
Choosing Science Teams
With science, it is often difficult to find a balance between providing students with as many hands-on experiences as possible, having plenty of science materials, and offering students a collaborative setting to solve problems. Any time groups have four or more students, the opportunities for individual students to speak and take part in the exploration process decreases. With groups of two, I often struggle to find enough science materials to go around. So this year, I chose to place students in teams of three! Picking science teams is always easy as I already have students placed in desk groups based upon behavior, abilities, and communication skills. Each desk group has about six kids, so I simply divide this larger group in half.
Gathering Supplies & Assigning Roles
To encourage a smooth running classroom, I ask students to decide who is a 1, 2, or 3 in their groups of three students (without talking). In no time, each student has a number in the air. I'll then ask the "threes" to get certain supplies, "ones" to grab their computers, and "twos" to hand out papers (or whatever is needed for the lesson). This management strategy has proven to be effective when cleaning up and returning supplies as well!
True or False
I invite students to join me on the front carpet with their science journals. I begin by projecting three true or false statements, True or False, on gravity to build interest and student investment. Right away, I heard students say, "I love true or false!"
1. On Earth, you will weigh less on a mountaintop than at sea level. (True: The closer you are to the center of the Earth, the more you weigh.)
2. Mass is a measure of the force of gravity on an object. (False: Weight is the measure of the force of gravity.)
3. An object on the sun will weigh more than the same object on the Earth. (True: The sun's gravity is 28 times stronger than the Earth's gravity.)
Next, I use the following posters to teach students the meaning of key vocabulary: Radius Poster, Diameter Poster, and Gravity Factor Poster. Later on in the lesson, students will reflect back on these posters and say, "Oh... now I get it!"
I want to inspire interest in today's lesson and capitalize on student curiosity, so I create two posters prior to the lesson:
1. I project and sketch a picture of the planets to help students visualize size of planets: Mass of Planets Chart. Here's what this chart will look like at the end of this part of of the lesson: Mass of Planets Chart.
2. Next, I project and sketch a Surface Gravity Factor Graph to help students compare the surface gravity factor on each planet: . (Notice how I only colored in Pluto, Earth, and Jupiter to begin with. I lightly pencil in a line for each of the other bars to complete later on. Surface Gravity Factor Chart. Here's what the completed chart will look like later on: Completed Surface Gravity Factor Chart.
The goal of making these two charts is to help students make connections between the surface gravity factor and the mass of a planet.
I copy pages 206-209 of the following link and pass out copies to every student. I ask students to first turn to page 209 to discuss the "What Would You Weigh on Jupiter" table as a class: What Would You Weigh on Jupiter Table. (Today, we will only look at this table. Tomorrow, we will read the rest of the text.)
*We make note that in 2006, Pluto became a "dwarf planet" and is no longer considered a planet. (This document was published in 2002.)
The Mass of Planets Chart
One by one, I ask students to help me label each planet with the correct mass, using the table in the reading handout. We begin with Earth. One student points out that the mass of Earth is 597.
I take this opportunity to explain that the mass of a planet is so large that we can simplify the number by using exponents. The mass of Earth is actually 597 x 10 to the power of 22. Let's look at 10 to the power of 2. (I wrote this on the board.) What does that equal? (100) We then discuss the answer to 10 to the power of 3, 4, and 5. Students realize that the number of zeros is equal to the exponent. We then agree that 597 x 10 to the power of 22 could be found by writing 22 zeros after 597: How much is 10 to the power of 22.
We then discuss and record the mass for the other planets until the chart is complete: Completed Mass of Planets Chart.
Surface Gravity Factor Chart
Moving on the the Surface Gravity Factor Chart, I ask students to turn and talk: What do you notice about the surface gravity factor on Pluto, Earth, and Jupiter?
Altogether, we discuss conclusions that we can make so far, based upon the mass and surface gravity factor of planets.
One student points out, "Jupiter its he biggest planet in our solar system."
Another student realizes that "The surface gravity factor increases as the mass of the celestial body increases." This was exactly what I was hoping for!
Now, I knew it was the perfect time to complete the Surface Gravity Factor Chart: Completed Surface Gravity Factor Chart! I began drawing in each of the missing bars on the bar graph. This left my students completely baffled! They couldn't believe that the gravity on Saturn is lower than the gravity on Earth!
We then returned to our Conclusions & Evidence T-Chart and a student added, "Surface gravity does not always depend on the mass of a planet.
What Would you Weigh on Jupiter
Before moving on to our investigation, I want students to make further sense of what affects gravity. Altogether, we read the text box next to the table: What Would You Weigh on Jupiter Table.
I draw a diagram on the board to help simplify these complex concepts: What Affects Gravity. Gravity is affected by mass. We know that the Earth has more mass than the moon which means that the Earth has greater gravity than on the moon.
However, what else affects gravity? (The radius/diameter) The further away you are from the center of the celestial body, the lower the gravity (similar to gravity on a mountain top and gravity at sea level).
Students are now beginning to make sense of gravity. I know it is time for students to experience this first hand before we continue on with this conversation!
Prior to the investigation, I labeled 10 empty soda cans with the names of the following celestial bodies (while keeping the weights a mystery): Labled Cans. I then filled each can with gravel (and water if needed) until they weigh the same number of Newtons that a can of soda would weigh at each location below. For Jupiter, I also had to add two large washers to the top of the can to increase the weight to 8.48 N: Jupiter. I skipped representing the weight of a soda can on the sun as it would take about 20 pounds of sand!
I introduce today's learning goal: I can determine the weight of a soda at different locations in the Solar System.
To connect today's goal with science standard 5-PS2-1, Support an argument that the gravitational force excerpted by Earth on objects is directed down, I ask students the following questions:
What is weight? (Weight is a measure of the force of gravity on an object.)
How do we measure the strength of the gravitational pull on an object? (Spring scale, measuring in Newtons)
Why are objects pulled downward on Earth and other planets in the Solar System? (Objects with mass are attracted to other objects with mass. The gravitational pull is much higher when one object has a large amount of mass, such as a planet. The Moon is smaller and has less mass than the Earth. This means that it exerts less gravitational pull on a can of pop than the Earth.)
I pass out a copy of the Weight of a Can of Soda Table to each student. Referring to all of the labeled pop cans, I explain: Today, I want you to actually experience how much a full can of soda weighs other places in the solar system besides Earth. Now, I've opened these cans and replaced the soda with sand, but I want to pretend that each can is actually a full can of soda, unopened and untouched! This way, you'll be able to feel how heavy a can of soda would be on the moon... on Jupiter... on Mars and many other places!
Using a Spring Scale
Pointing to the second column on the Soda Can Weight Table, I ask students to work in their teams of 3 to measure the weight of each can in Newtons. I take the time to project a 10 N. spring scale and to discuss how to use the scale to read decimal increments, such as 0.8 N. I draw the following diagram on the board to help read the Decimal Scale.
Providing Actual Weights
Yesterday, some students were frustrated that they weren't able to measure the exact weight using the spring scale. To avoid this frustration today, I randomly wrote the weights of a soda on a white board: Weights of a Soda. This way, students could look at both the spring scale and the possible weights to determine the exact weight of a soda throughout the solar system.
Rotating Soda Cans
To begin, I ask a member of each group to grab a can from the counter and a 10 N spring scale. Next, I ask all groups to weigh their can using their spring scales. After students record the weight of their can using the spring scale, they pass the can to the next group. This way, each group of students will have the opportunity to weigh each can of soda.
Monitoring Student Understanding
Once students begin working, I conference with every group. My goal is to support students by asking guiding questions (listed below). I also want to encourage students to engage in Science & Engineering Practice 7: Engaging in Argument from Evidence.
Here, Identifying the Weight of Neptune, students utilize their spring scale and the listed weights on the white board to identify the weight of a can of pop on Neptune. It was great to see them using all their resources.
Another group, Reading a Decimal Scale, needs a refresher on reading the decimal scale. In no time, they are ready to apply this mathematical skill.
Although we didn't have time to reflect on student findings during today's lesson, tomorrow, we will take a closer look at the data collected by making a bar graph. We will also continue exploring the weight and mass of objects on other celestial bodies by reading the rest of the reading handout.