The element consists of a mantle of an upright truncated cone and a climbing frame above it. Access to the element is from the lower side, and there is a climbing frame above the cone that allows observing the motion of other STEM park users by climbing the frame and looking from above. The upright cone is a geometric body formed by rotating a right-angled triangle around its cathetus and is bounded by a circle and a curved surface. A truncated cone is formed by rotating a rectangular trapezoid around a side that is perpendicular to two sides of the trapezoid and is bounded by two circles and a curved surface (mantle). The truncated cone whose mantle forms this element is bounded by a circle with a diameter of 200 cm and a circle with a diameter of 60 cm. The height of the truncated cone is 120 cm.
We can explore the movement of balls along curved surfaces, rotation, friction, and free fall on this element. The ball that you throw out of your hand is only affected by the force of gravity and friction, which acts against the direction of the ball’s movement. You can notice that the ball moves faster in the lower part and slower in the higher part of the cone. The energy that you initially gave to your ball is constantly being transferred from potential to kinetic (energy of motion) and vice versa, but with each passing moment the total energy, due to friction, decreases. Unless we catch the ball again, it will surely fall to the floor once it loses speed.
Paths along which the balls move are very unusual, and the influence of gravity and friction can be recognized in them. Momentum and velocity change in very interesting ways. Due to the unusual movement of balls, it seems to us that the entire geometry of space in this truncated cone is slightly curved.
- Take a ball, for example, a tennis ball, and start exploring.
- Try to throw the ball so that it follows the drawn curve.
- By using your body and arms, try to form two vertical sides of the trapezoid whose rotation formed this truncated cone. Can you determine the lengths of some of its sides?
- By using your ball, try to make something resembling an ellipse.
- Is it possible to draw a circle with a ball?
- Try to form a trajectory resembling a parabola.
- How should we throw the ball to make it spin on a curved surface for the longest time?
- What is the largest number of balls that you can simultaneously catch and throw along the surface?
- If you throw several balls along the surface in the same direction (using the same hand), can they collide?
- If the ball bounces off the surface instead of rolls, can it stay above the ground longer than a rolling ball?
