Scientific Method/Variables
What is the first step of the scientific method?
make an observation
What kind of heat transfer happens when you touch a hot metal spoon?
Conduction
the sun
What does it mean if an energy source is renewable?
It can be replaced naturally in a short amount of time
When an object is moving, what kind of energy does it have?
Kinetic Energy
Explain what is a hypothesis?
An educated guess that can be tested.
Warm air rises and cool air sinks in a room. What kind of heat transfer is this?
Convection
What device changes sunlight into electricity?
solar panel
Give two examples of renewable energy and two examples of nonrenewable energy
Renewable – solar, wind. Nonrenewable – coal, oil.
A roller coaster is at the very top of a hill. What type of energy is greatest at that point?
Potential Energy
In an experiment testing how sunlight affects plant growth, what is the independent variable
amount of sunlight
Heat always moves from a place that is ___ to a place that is ___.
hot to cold.
Why is solar energy considered renewable?
The Sun will keep producing energy for billions of years
Explain why coal and oil are considered nonrenewable resources.
They take millions of years to form and cannot be replaced quickly once used up
A ball is rolling down a hill. As it rolls, what happens to its potential and kinetic energy?
Potential energy decreases while kinetic energy increases.
Explain what is the dependent variable in an experiment?
The variable you measure or observe
What type of heat transfer happens from a bonfire.
radiation
What is the main disadvantage of using solar energy?
It cannot be used at night or on very cloudy days
A city wants to build a new power plant. They can choose between a coal plant or a solar energy system.
Which one should they choose if they want long-term sustainability, and why?
The solar system — it’s renewable, produces no greenhouse gases, and the Sun’s energy won’t run out.
What is the potential energy of a 2 kg ball sitting on a 3 m shelf?
58.8 J
A student tests how different amounts of fertilizer affect tomato plant growth. Please provide at least 2 controlled variables.
Type of plant, amount of sunlight, same pot, etc.
A metal pot is sitting on a hot stove. The handle begins to get hot. What kind of heat transfer is that?
Conduction
Explain how solar thermal systems and solar electric systems both use the Sun’s energy, but in different ways. Please provide an example of each type.
Solar thermal systems use sunlight to produce heat, usually to warm water or air. (example: heating up a pool)
Solar electric systems use photovoltaic cells to convert sunlight directly into electricity. (example: solar panels)
Is Biomass renewable or non renewable?
renewable
When a car stops, its brake pads and wheels get very hot. Describe what energy transformations happen during braking.
The car’s kinetic energy changes into heat energy due to friction between the brake pads and wheels and gets released as thermal energy.