Introduction
In this lesson, students explore the concept of what a force is and how forces affect our lives. The force of gravity is continually playing a role in our lives. In this lesson, students are asked to think of other forms of forces shaping their lives.
Learning Objectives
- Students will be able to define “force”
- Students will be able to demonstrate an understanding of force and motion in the activity
- Students will be able to understand the concept of force and how it feels on Earth vs. in space
Vocabulary
- Force
- A push or pull upon an object
- Gravity
- The force that attracts a body toward the centre of Earth, or toward any other physical body having mass
- Inertia
- The tendency to do nothing or to remain unchanged
- Friction
- the resistance that one surface or object encounters when moving over another
What Is Force?
Guiding question: What is a force? How do forces act on humans on Earth and in space?
The gravitational pull is constantly acting and interacting with our lives. Forces and motion are part of everything we do. How do we know what forces are acting on us or on an object? Can we predict how the laws of motion will affect an object?
Newton’s Law
There are three laws of motion discovered by Isaac Newton:
Law 1: An object that isn’t being pushed or pulled by a force either stays still or keeps moving in a straight line at a constant speed. Inertia is an object’s tendency to resist any change in its motion. A body in motion stays in motion.
Law 2: Forces make things move. The bigger the force and the lighter the object, the greater the motion.
Law 3: Every action has an equal and opposite reaction.
Watching Activity
Gravity on Earth vs. in Space
To understanding the force of gravity, ask the students a few guiding questions:
- What is gravity?
- Where is gravity?
- What does gravity do?
After a discussion around these questions students will have a basic understanding of what a force is. Does the force of gravity change based on where you are in the universe? On Earth, it acts in a particular way, so would it change if you are in space? Ask the students to ponder this question: Is there gravity in space? And then watch this video.
Activity
Students conduct an experiment in landing an object onto a target. In this activity, the students hypothesize how best to land the object onto a target depending on the weight and size of the object. As they observe a variety of approaches, the students will see how to approach a particular landing based on the object’s size and weight and how gravity plays a part in the outcome.
Landing a spaceship target
Materials
- 3m of smooth line (e.g., fishing line, kite string, or dental floss)
- 1 index card
- Different balls or objects (e.g. a tennis ball, marble, rubber ball)
- 1 paper clip
- 1 medium-size paper cup
- Target drawn on a piece of paper OR printed PDF
- Masking tape
- Scissors
- *Don’t worry if you don’t have all of the materials. Be creative and substitute materials with what you have! It’s part of the design process.
Step 1: Set up
Tie the smooth line between two desks to create a zipline. Place a paper target on the floor in the middle of the line.
Step 2: Brainstorm
Have the students choose their object, some may choose the marble, some may choose the tennis ball and so on. Ask the students to hypothesize how their object will fall onto the target. Students should come up with a plan of action while considering the following:
- How will they drop the object onto the target?
- What will need to happen to hit the target?
- Will the object travel inside?
- How will your spacecraft release the marble lander while zipping down the line?
Consider whether you will use an automatic release system or a remotely activated release system.
Step 3: Build it
Based on the brainstorming, the students now create their spacecraft.
Step 4: Test and Evaluate
Try it out! Have the students execute their experiment. Taking turns to demonstrate their contraption, ask the students to watch their peers experiment. Observing how the target fell, ask the students: how did your spacecraft work? Did you achieve your desired goal? Was there one in particular that worked the best and why?
Step 5: Redesign
Now the students have seen how their plans have worked or not worked and how their classmates’ plans have worked. Based on their observations, they will redesign their spacecraft to accommodate their observations.
Once students have completed the activity, ask them to describe what happened in their experiment using some of the vocabulary words of the lesson. Ask them to explain the force of gravity using different sizes and weights of the objects and which was the most successful experiment.
Conclusion
To conclude this lesson, students engage in a discussion around forces in everyday lives. Have the students write in their journals a list of examples of forces and motion we see everyday. How are they acting on us and why? As they are writing out their list, ask them to use 3–5 forces and motion vocabulary words.
Additional Resources
- Gravity Compilation: Crash Course Kids – addresses several commonly-asked questions about gravity, including “does gravity really pull you down?” and “how does gravity work in space?”
