Teaching Kids About Gravity With Science Experiments
Teaching children about gravity can be an exciting and engaging process. The force of gravity is a key part of scientific investigation and can be viewed in a number of experiments.
From balancing objects to an egg drop challenge, these fun science experiments will help children learn about the gravity of our planet.
Dropping an Object of Different Masses
Named after Galileo, this classic experiment demonstrates how weight and gravity interact. Students can try this experiment themselves by dropping objects of different sizes and weights from the same height, observing which object hits the ground first. Depending on the type of object and how it’s dropped, some will have more air resistance than others, which can also affect their speed of fall.
When this is the case, heavier objects will fall slower than lighter ones. However, as long as both are accelerated to the same initial speed and start at the same height, they should hit the ground at the same time, regardless of their mass. In this video, a NASA astronaut recreates Galileo’s centuries-old demonstration by dropping both a falcon feather and hammer from the Moon and observing which one hits the ground first. It’s an eye-opening way to reinforce the concept that size, not weight, determines acceleration on Earth. It’s also a great way to get students talking about forces, including gravity.
The Bernoulli Experiment
Bernoulli experimented with fluids that flow to discover an important principle: a moving fluid will exchange its kinetic energy for potential energy. This is why the pressure of a flowing fluid decreases with increasing velocity. It is also why an airplane wing needs to have a certain amount of lift.
The mathematical physicist Daniel Bernoulli (1700-1782) discovered the law that bears his name while conducting experiments concerning another fundamental concept: the conservation of energy. This principle states that a system isolated from outside factors maintains the same total amount of energy, though energy transformations do take place.
A Bernoulli trial is an experiment that has two possible outcomes — either success or failure. The classical example is a coin toss, where heads is considered success and tails is considered failure. This type of experiment is also called a binomial experiment because it involves multiple trials.
The Torsion Balance Experiment
Understanding gravity is a key element of physics and astronomy. Students can test the force of gravity using a variety of hands-on experiments, including creating a galaxy in a bottle, dropping objects of different weights, and determining the center of gravity. These simple experiments can be performed at school or at home.
In the Cavendish experiment, a torsion balance was used to measure the weak gravitational force between lead balls. The balls were suspended from a rod that was bent by a force (or torque) equal to the weight of each ball. Measurements of the twist in the wire were recorded and compared to known values for the size of each mass to determine the value of the gravitational constant, G.
This Cavendish experiment is a great way to introduce the scientific method to students. This process of predicting outcomes, making observations, and explaining results is critical for children to understand how science works. Moreover, these experiments are designed to engage children with the concept of gravity in ways that will help them see it at work in their everyday lives.
The Weight Experiment
Physicists are convinced that virtual particles contribute to gravity, but they don’t know how to measure this contribution. The sensitivity required to detect these tiny deflections would be much higher than the laser-and-mirror setups within gravitational-wave detectors.
This simple experiment shows how gravity affects objects of different mass. It also demonstrates that the size of an object’s mass doesn’t change its weight.
To perform this experiment, fill a container about an inch deep with flour. Lay a sheet of newspaper or a baking sheet underneath to avoid making a mess! Drop marbles or rocks into the flour and watch them create “craters” in the dough. The bigger the crater, the more impact the object had when dropped!
Explain to students that this is why a person’s weight is less on the Moon than on Earth. Then ask students to calculate their own weight on each planet by multiplying their mass with the surface gravity of that planet.