🛠 Forces & Motion
What You'll Learn
- Define force and explain how it changes motion
- Understand gravity, friction, and applied force
- Predict how a ball rolls down a ramp based on height and surface
What Is a Force?
A force is a push or pull that can change an object's speed, direction, or shape. Forces are measured in Newtons (N).
Common forces:
- 🌍 Gravity — pulls everything toward Earth's center (weight)
- 🔨 Friction — resists motion between two surfaces (rough surface = more friction)
- 😊 Applied Force — a push or pull you apply yourself
- 🔹 Air Resistance — friction from air (slows falling objects)
- ♿ Normal Force — surface pushing back up on an object (your chair pushing up on you)
When forces are balanced (equal on all sides), objects stay still or keep moving at the same speed. When forces are unbalanced, motion changes — the object speeds up, slows down, or changes direction.
Gravity & Ramps
A ramp (inclined plane) converts gravity's downward pull into movement along the ramp's surface. A steeper ramp gives more acceleration because gravity's component along the ramp is larger.
🛠 Virtual Lab: Ramp & Ball Experiment
Adjust the ramp angle and surface type. Click Release to send the ball down the ramp!
Course Complete!
You finished 3rd–5th Grade Science! You explored the scientific method, living things, plants, animals, weather, matter, simple machines, light, the water cycle, and forces. Real science is in everything around you!
Explore More Courses →What is friction?
A steeper ramp makes a ball roll: