Turn your home into a physics lab using everyday items you already have. No special equipment needed ā just curiosity and creativity!
Tie the weight: Securely tie the spoon to one end of the string. Make sure the knot is tight so it doesn't slip during swinging.
Set the length: Hold the other end of the string and measure the length from your hand to the center of the spoon. Start with 50 cm.
Start swinging: Pull the spoon to one side (small angle, about 15Ā°) and release. Don't push ā just let gravity do its thing!
Time 10 swings: Use your phone timer to measure how long it takes to complete 10 full back-and-forth swings. Divide by 10 to get the period (T).
Change the length: Make the string shorter (25 cm) and repeat. Notice how it swings faster! The period gets shorter.
The time period T = 2Ļā(L/g) depends ONLY on the length (L) and gravity (g). Shorter strings mean smaller arcs and faster oscillations. This is exactly how grandfather clocks kept perfect time ā by adjusting the pendulum length! The mass of the weight doesn't matter at all (as long as it's not too heavy for the string).
Test 1 - The sock: Hold the balled-up sock at shoulder height. Start your timer and drop it. Stop when it hits the ground. Record the time.
Test 2 - Flat paper: Now do the same with a flat sheet of paper. Notice it takes much longer! Why?
Test 3 - Crumpled paper: Crumple the same paper into a tight ball and drop it again. Suddenly it falls much faster ā almost as fast as the sock!
Test 4 - The book trick: Place the flat paper on top of the book. Drop them together. The paper falls at the same speed as the book! The book shields it from air resistance.
Gravity pulls all objects down with the same acceleration (g = 9.8 m/sĀ²) regardless of mass. But air resistance opposes motion. The flat paper has a large surface area fighting through air, so it falls slower. When you crumple it or shield it with a book, air resistance becomes negligible ā and it falls at the true rate gravity dictates. In a vacuum (no air), a feather and a hammer fall at exactly the same rate!
Hang the rubber band: Loop the rubber band around a doorknob or hook. Let it dangle freely. Mark this position as zero.
Attach the cup: Use tape to secure the paper cup to the bottom of the rubber band. This is your "weight basket."
Measure zero point: Place a ruler vertically next to the cup. Record the position of the cup bottom as your "0 coins" mark.
Add weight progressively: Add 1 coin to the cup. Measure how far the band stretched (in cm). Repeat with 2, 3, 4, 5 coins.
Plot the graph: On graph paper, plot Coins (x-axis) vs. Stretch (y-axis). You'll get a beautiful straight line!
This demonstrates Hooke's Law: F = kx. The force (weight of coins) is proportional to the extension (stretch) of the elastic material. The slope of your graph is the "spring constant" (k) ā how stiff your rubber band is. Professional scales use the same principle with metal springs instead of rubber bands. The straight-line graph proves that extension is directly proportional to force!
Create the launcher: Place one end of the ruler on the edge of a table. Let half of it hang over. Place books on the table end to anchor it.
Place projectile: Put the eraser on the overhanging end of the ruler. This is your "launch platform."
Launch angle test: Hit the end of the ruler downward with your hand. The eraser launches! Use masking tape to mark where it lands.
Change launch angle: Stack more books under the ruler to change the angle. Try 30Ā°, 45Ā°, and 60Ā° (estimate with your eye). Which angle gives maximum range?
Measure and compare: For each angle, do 3 launches and measure the average distance. Record your results!
The eraser follows a parabolic path ā just like basketballs, arrows, and cannonballs. Maximum range occurs around 45Ā° (in theory), but air resistance and the ruler's limitations might shift this slightly. The horizontal velocity stays constant while gravity pulls the eraser down in the vertical direction. These two independent motions combine to create the curved trajectory you see!