The Scientific Method
The scientific method is used to guide scientists as they perform experiments. Following these steps allows for fair trials that result in discoveries widely accepted by other scientists. This is not a linear process; rather, scientists can go back and repeat steps or revise steps as needed to reach an accurate conclusion. The following is a general order to follow, with examples.
- Identify a problem or ask a question.
Example: What type of water helps plants grow best?
- Make observations and do research about the problem.
Example: Read about other experiments and interview farmers and gardeners.
- Develop a testable hypothesis, or educated guess, as to the outcome of the experiment.
Example: If plants are grown with different types of water, then spring water will produce the tallest and most robust plants.
- Conduct the experiment using one independent variable. The variable is the one thing that is changed from one group to the next.
Example: One group of plants are grown with tap water, one group with spring water, one group with sparkling water, and one group with distilled water. All other variables are kept the same, such as soil amount and type, plant type, amount of sunlight, amount of water, etc.
- Record data.
Example: Record the height of the plants at set intervals, measure leaf size, take pictures to record leaf color, identify flower growth, etc.
- Draw conclusions.
Example: Determine the type of water that is the most effective based on the recorded data. At this point, the experiment can be redone with a new hypothesis and variable or with the same hypothesis to verify results.
Types of Rocks
There are three types of rock: igneous, sedimentary, and metamorphic. Each type of rock can be changed into the other types of rocks, depending on how they are changed.
An igneous rock forms from molten rock that has cooled. Intrusive igneous rock forms inside a volcano and cools before it reaches Earth’s surface. Extrusive igneous cools on Earth’s surface. Rock must have been melted in order to be igneous.
Metamorphic rock is formed from extreme heat and pressure. Existing rocks are “morphed” or changed, which causes lines or streaks to appear throughout the rock. This occurs as different minerals respond differently to the heat and pressure.
Sedimentary rock is formed by cementation and compaction. Current rocks are broken into smaller pieces and then compacted and cemented together. This creates a layered look or a conglomerate look where the small chunks are still recognizable but glued together.
Phases of the Moon
The Moon revolves around Earth at the same rate it rotates. It takes about 28 days for this to occur. This means that from Earth, we always see the same side of the moon. The amount of the moon that is reflecting the sun varies and we call the different amounts of light seen moon phases.
The main moon phases are the new moon, first quarter moon, full moon, and third or last quarter moon. The new moon reflects no light and therefore is not visible in the night sky, while a full moon is a bright, large circle. The right half of the circle is reflecting light during the first quarter moon and the left half is reflecting during the third quarter moon.
The first quarter moon looks as if a capital D has been lit and a third quarter moon looks as if a capital C has been lit. When given a diagram, you can identify the main moon phases by remembering that to go to the moon, you must be a “DOC”: D for first quarter, O for full moon, and C for third quarter.
Between the main moon phases, the Moon continues to become more or less lit. When it is reflecting more light, it is called waxing. When the reflection is decreasing, it is called waning. The thin sliver of moon that is reflected before and after a new moon is a crescent moon. The mostly reflective moon before and after the full moon is a gibbous moon. Three to four days after a new moon, a waxing crescent moon is visible. Then the first week after a new moon ends with a first quarter moon. Three to four days after a first quarter moon, a waxing gibbous moon is visible. Then the second week ends with a full moon. This is the halfway point of the moon cycle. Three to four days after a full moon, a waning gibbous moon is visible. Then the third week ends with a third quarter moon. Three to four days after a third quarter moon, a waning crescent moon is visible. Then the fourth week ends with a new moon and the cycle begins again.
Weather vs. Climate
Weather consists of the daily conditions outside. The current temperature, precipitation, and cloud cover are part of the weather. Climate is the general weather trend over a period of time. The climate of an area is the average temperature, precipitation, and conditions over a longer period of time.
Heat can be transferred in three ways: conduction, convection, and radiation. Conduction is the transfer of heat by touch. This can be seen when a pot on a stove is touching the electric burner. The burner conducts heat into the metal of the pan. Convection is the transfer of heat by a fluid (a liquid or gas). This occurs when hot air is blown onto food in a convection oven or the hot water at the bottom of a pot rises to the top and warms the cooler water at the surface. Radiation is heat being transferred by electromagnetic waves. The Sun heats the Earth by radiation.
Asexual reproduction is reproduction that requires only one parent, and which produces a clone. The offspring will have DNA identical to the parent. Bacteria, hydra, worms, strawberries, and some snakes can reproduce asexually.
In order for asexual reproduction to occur, the cell must go through mitosis. Mitosis has four phases that must occur sequentially: prophase, metaphase, anaphase, and telophase (P-MAT). During prophase, the nuclear envelope breaks down, spindles form, and the chromosomes condense. Then, in metaphase, microtubules attach to the chromosomes, which are lined up across the middle. Anaphase pulls the chromosomes apart and toward each end of the cell. Telophase then begins when the spindles disappear and a nuclear membrane forms around each set of chromosomes. The cell then goes through cytokinesis, during which it divides completely, resulting in two cells with DNA identical to the original or parent cell.
And that’s some basic information about the test.