Actual age in geology means the accurate age of geological events or other substances. Relative age is the estimated age calculated.

For dating the relative age, there are some principles such as superposition and original horizontality.

Superposition is the deepest point humans can get on Earth; the deepest humans can get was once bedrock (that's how they named it), but they dug even deeper after that, so they came out with another name for the deepest point. The superposition can be changed.

Original horizontality is the term that describes how most rocks form in horizontal layers, so people can know that the layers below are older and the stones that have just formed are at the top.

Adaptations and variations exist because organisms need to compete with other or the same species for limited resources or prey, and avoid predators. 

Genetic variations are mainly about the mutations, which are random changes in the DNA sequence. And there are environmental variations because of their living conditions, the system sometimes develops the kids' bodies, such as making some useless structures disappear.

Some organisms are born randomly with different body structures or functions compared to the same kind. And if the variation benefits its survival or reproduction, it would have spread its genes wider than others. So the certain organism would pass down its traits to the generations after, that is how adaptations occur.

An experiment we have done is writing down data on the sunflower seeds. We have 10 sunflower seeds, and we measured the length and thickness of each seed. We discovered the difference between them and discussed why they have different colors. 

We came up with an answer that they are toasted, and we think the darker each seed is, the longer it is toasted. 

Then, we realized that every seed has a different thickness and length, and the data of our 10 seeds is different compared to the 10 seeds from another group.

This experiment shows the variation between the seeds and the excellent taste (according to classmates who ate some after the experiment).

Genetic engineering is the action of replicating an organism's genes. It can produce improvements in agriculture, such as making the original bananas that contain large seeds into the ones we eat today, or tomatoes that can be picked while they are green and ripen during transportation.

Food that has been through genetic engineering is called "genetically modified organisms", or "GMO".

Some people might not like genetically modified food, so some stores label GMO products (or products that are non-genetically modified).

However, genetically modified crops are safe for eating. 

Fossils are more than the dinosaur bones we see in museums.

 Fossils form in rare conditions (high temperature, high pressure, specific places). Some parts of an organism's body, mostly the hard parts such as bones, teeth, or shells, might become fossils. Here are two ways fossils form. 

Mineralization, when the rock-forming minerals fill in the spaces in an organism, most of the whole structure inside the organism would remain. 

Carbonization is the organism's liquid and gas are removed under high pressure, leaving only the carbon outline or film.

I enjoy the part where we create our own timeline on the whiteboard, where we write down and discuss the major events in our growing process.

We brainstormed a lot of our past experiences, such as when we started learning English, our first time traveling, and when we went to summer camp together...

This activity can encourage sharing our perspectives, and let us know more background information about the environment my classmates had before VIS.

The most important part, that it combines learning relative age and absolute age. Some of the timing was based on accurate memory, and some was based on us guessing when this event happened.

F=ma means the force (F) on something is its mass (m) times how fast it speeds up (acceleration, a).

When pushing or pulling an object, the force changes its motion by making it speed up, slow down, or change direction. 

The heavier the object (more mass), the harder you have to push to change its motion. So, force causes motion to change. The bigger the force, the more the motion changes, and the bigger the mass, the less it changes for the same force. This is how force changes motion simply and clearly. 

Friction is a force that resists the motion between two surfaces that are touching.

It always acts in the opposite direction of movement. Because of this, friction slows objects down, reduces their speed over time, or can stop them completely. High friction makes motion harder, like pushing a box on rough ground, while low friction allows smoother movement, like sliding on ice. Friction also creates heat. Overall, it controls how easily objects start moving, keep moving, or come to a stop, and enable many everyday activities like walking and driving.

We paired up and did an experiment of pushing table tennis balls. We got two balls and two pieces of tape. We pushed a ball towards the other. The ball we pushed was supposed to hit the other ball, and the two balls would bounce apart. Although my group kept failing to make them touch, we assume that balls bounce apart because when we pushed them together, they compressed and pushed back with equal and opposite forces (Newton’s Third Law). Their elasticity stores energy during compression and releases it, causing them to move apart.

Potential energy and kinetic energy are two main forms of mechanical energy. 

Potential energy is stored energy related to an object’s position or height. For example, a book on a shelf has gravitational potential energy because gravity can pull it down. The higher the height, the greater the potential energy. 

Kinetic energy is the energy of motion. When the book falls, its potential energy is transformed into kinetic energy as it moves faster. 

Objects with greater mass and/or speed have more kinetic energy.

One important type of non-contact force is the magnetic force. 

Magnetic force acts at a distance and does not need physical contact between things. It happens due to magnetic fields made by magnets or moving electric charges. For example, a bar magnet can attract iron nails even when they are not touching and from a distance. 

The Earth has a magnetic field, which helps compass needles point north. Magnetic force is closely connected to electric forces and is part of electromagnetism.

The concept I like the most in this unit is the part about calculating kinetic energy and how energy transforms between kinetic and potential energy. I like this part because it's basically math, and easy math. 

We know that doubling the mass of an object causes its kinetic energy to double as well. However, doubling the speed causes the kinetic energy of an object to become four times as large (since the speed is squared) (KE = ½mv^2). 

Also, the point I like the most is that the answers after calculation are always clear, and it didn't take many brain cells to remember the formulas (I don't enjoy taking notes and remembering, so I am also failing to recall the historical concepts in social studies).