Welcome to the DC Digital Lab!

Our team has put together a collection of videos, experiments and activities that you can do at home. We are here to help you overcome boredom and learn a few things in the process! Simply click the image or video to start your at home discoveries.

 

What Falls Down...

Have you ever seen an acorn fall from a tree? Maybe you have heard the tale of Isaac Newton getting inspired by apple hitting him in the head. The idea that objects fall from elevated surfaces is not new. This action is called gravity! When Isaac Newton was a young scientist, he began conducting theories on gravity. In 1687 Isaac Newton published 20 years’ worth of research on gravity. Today the idea is called Newtons Law of Gravitation.

What is gravity?

On Earth, gravity gives an object weight and pulls objects toward the center of earth. Gravity is the mutual attraction between two objects in the universe. Gravitational forces naturally occur between any objects that have mass and energy and pulls them together. This includes planets, stars and even other galaxies. Some objects have more gravity than others. An example of this would be that Earth has a stronger gravitational pull than a person. This is why when an object falls it is drawn to the Earth and stays on the ground, rather than being drawn to the person.

Relationship Between Mass, Weight and Gravity

Mass is the amount of matter in an object. A person’s mass is the same no matter where they travel in the universe. On the other hand, a person’s weight will change from place to place. Mass and weight can be measured in kilograms. When talking about change of weight from place to place, a scientist would typically use Newtons to measure weight instead of kilograms. In the image above you see an astronaut that weighs 980 Newtons and has a mass of 100kg. When the same astronaut travels to the moon the mass stays at 100kg and the weight changes to be 162.2 Newtons. How does this occur? The Earth has 60% more mass than the moon. The more mass an object has the more gravitational force it has. Due to the smaller mass on the moon, an astronaut would weigh less because of the lower force of gravity.

Relationship between the Moon, Earth and Sun

The Moon, similarly to Earth has its own gravity. You have previously learned that the gravity of Earth is larger than the gravity on the Moon. The Moon is known as “Earth’s natural satellite”, due to this relationship, it causes the Moon and Earth to be attracted to each other. This can explain why the Moon is in orbit with Earth. The gravity between the Earth and Moon causes them to orbit each other. The Moon’s pull on Earth is what causes the tides to change. High-tide is when the Moon’s gravitational pull is the strongest. Low-tide is when the Moon’s gravitational pull is the weakest. These tidal changes can be measured by the routine path of moons orbit due to its gravitational pull towards Earth. This information can be applied to the Sun and the arrangement of our solar system. The Sun is the biggest star in our solar system, and has the most mass. These components created a perfect arrangement of our solar system. The suns gravitational pull on each planet is unique to the distance of the Sun, due to the immense gravitational pull it attracted all the elements in our solar system to orbit the way they do now.

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Falling Objects Activity

In this experiment, you will practice dropping two objects at the same height, at the same time. When looking at your objects take a guess at which items will hit the ground first and write down your ideas. Once the experiment is finished, look back at your old answers and make changes as needed.

MATERIALS

  • 1 full apple
  • 1 apple cut in half
  • paper
  • Pens, pencils, any miscellaneous objects
  • Video recording device (optional)
  • (NOTE: when you drop an apple it can be messy, keep this in mind when you do the experiment)

PROCEDURE

  • Hold a full apple in one hand, and the half-cut apple in the other. Before you test the apples, make sure they are dropped at the same height at the same time. (Using a video recording device will make this easier to see which item drops first)
  • Once you do this experiment with an apple, do it again with a pencil and a pen. Record your findings.
  • Conduct your experiment a third time, one with an apple and one with a pencil or pen. Record your findings.
  • Repeat all procedures multiple times

EXPLINATION

If you did this experiment correctly the items should have fallen at the same time! You have previously learned that when an item falls on Earth it falls to the Earth because of gravity. The objects fall at the same time because they are experiencing the same gravitational pull.

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Floating Water Activity

MATERIALS

  • Water
  • Plastic Bottle
  • Bottle cap with a hole in it
  • 1 index card

PROCESS

  1. Fill your bottle almost to the top with water then attach the clear bottle cap with a hole in it
  2. Cover the hole in the with an index card then turn the bottle upside down.
  3. Take the card away take the card away. What do you see?

Why do you think the water didn’t fall out when you took it took away the index card? Why did it fall out when you tilted or shook the bottle?

EXPLANATION

The first reason is called cohesion. This happens when the tiny pieces that make up water, called molecules which are too small for you to see try to stick together.

The second is called adhesion this is what happens when one kind of molecule sticks to another kind of molecule. In this case it’s why the water molecules stuck to the plastic in the bottle cap.

Together cohesion and adhesion created a thin layer of water over the whole in your bottle cap which stopped the bottle from leaking when you shook or tilted the bottle, you broke that layer so the water started pouring out. When cohesion makes molecules stick together Scientists called the effect surface tension.

 

 

Video Experiments and Activities

DIY Science PDF experiments

Virtual Critter Corner