1
What type of surface reflects light best?
Smooth, polished surfaces (like mirrors).
What force pushes upward on objects in water?
Upthrust (buoyant force).
What ancient scientist shouted "Eureka!" about displacement?
Archimedes.
What do we call a flat mirror?
Plane mirror.
What symbol represents a battery in circuit diagrams?
Long and short parallel lines.
At what angle does light reflect off a mirror compared to its incoming angle?
angle of reflection
Why do periscopes use mirrors?
To reflect light around objects
What measures if an object floats?
mass of displaced water.
What unit measures electrical strength for components?
Volts (V).
What happens to a ball thrown at an angle when it bounces?
It bounces at the same angle.
Why is a lake reflection less clear than a mirror's?
Water isn't perfectly smooth (tiny waves scatter light).
How could you make a 3V battery from 1.5V cells?
Connect two cells in series.
Why don’t circuit diagrams use pictures of components?
Symbols are faster and universally understood.
What two forces act on a floating object?
Weight (gravity) and upthrust.
How does a periscope’s mirror work?
Two mirrors at 45° angles reflect light twice.
Design a circuit diagram for a lamp powered by two 1.5V cells.
Two cell symbols in series connected to a lamp symbol.
Explain why a heavy metal ship floats but a small rock sinks.
Ship displaces more water (upthrust > weight).
Calculate: If light hits a mirror at 30° to the normal, at what angle does it reflect?
30° from the normal.
Why must periscope mirrors be perfectly angled?
To ensure light reflects correctly to the eyes.
How does voltage affect a buzzer vs. a lamp in a circuit?
Buzzer needs exact voltage; lamp may work at lower voltage
Predict: What happens if a 6V buzzer is used with a 3V battery?
Buzzer won’t work (needs higher voltage).
When light hits a mirror, how does the reflected angle compare to the incoming angle?
They are equal
If a periscope has two mirrors, why must they face opposite directions?
To bounce light down and then up to your eyes.
What do the long and short lines in a battery symbol tell us?
Long line = positive (+), short line = negative (–).