RESPIRATION & BREATHING
What gas must enter the bloodstream during gas exchange?
Oxygen
In a sugar–water solution, which substance is the solvent?
Water
What is the unit of force?
Newton (N)
What is a pivot?
The fixed point around which a lever turns.
What is the variable a scientist deliberately changes called?
Independent variable
Which muscle contracts and moves downward when you breathe in?
Diaphragm
A solution is described as “concentrated.” What does this mean?
It contains a large amount of solute compared to solvent.
What happens to an object when forces acting on it are balanced?
Its motion does not change (stays still or continues at constant speed).
What is the equation for calculating a moment?
Moment = force × perpendicular distance from pivot
What is the variable a scientist measures called?
Dependent variable
What is the function of the alveoli (air sacs) in the lungs?
They are the site of gas exchange (oxygen in, carbon dioxide out).
Why is pencil used instead of pen for drawing a baseline in chromatography?
Graphite is insoluble in the solvent, while pen ink would dissolve.
What is the equation for speed?
Speed = distance ÷ time
If Marcus applies a force of 500 N at 2 m from the pivot, what is his moment?
1000 Nm
Thomas is investigating how the volume of a drink affects how quickly the drink will warm up. What is the independent variable?
The volume of the drink
State the difference between breathing and respiration. Daily Double (two answers for double the points)
Breathing is moving air in and out of the lungs; respiration is releasing energy from glucose in cells.
What is the difference between dissolving and melting?
Dissolving involves a solute and solvent forming a solution; melting is a solid changing to a liquid.
State the equation for pressure.
Pressure = force ÷ area
What must be equal for a seesaw to balance?
The force and/or the moment must be equal.
In Thomas' experiment, what qualities of the experiment should be kept the same? Daily Double (answer two for double points)
Room temperature, type of drink, container type, starting temperature.
Explain why larger mammals need a greater total surface area of alveoli than smaller mammals
Larger mammals need more oxygen for more body cells, so they require a larger surface area for faster gas exchange.
Explain why a darker-colored copper sulfate solution is more concentrated.
The darker color shows more copper sulfate particles dissolved, meaning a higher concentration.
Explain why increasing the area under an object decreases pressure.
The same force is spread over a larger area, reducing the force per unit area (pressure).
Explain how sitting further from the pivot helps a lighter person balance a heavier person.
Increasing distance increases moment, so a lighter person can produce the same turning effect by sitting farther out.
Why is it important to keep control variables the same in an investigation?
So that only the independent variable affects the results, making the test fair and valid.