What happens when a substance undergoes a physical change?

Compare your answer to the previous question with your observations in conducting this experiment. Discuss whether energy was conserved in your experiment. Was friction negligible

Why do balloons make noise when they pop?

Consider a helium balloon on a string tied to the seat of your stationary car. The windows are closed, so there is no air motion within the car. The car begins to accelerate forward. Which way will the balloon lean, forward or backward

Oil and water placed in a jar will separate. Even when shaken and mixed, the oil still separates from the water. Which best describes oil and water? Oil and water are highly soluble because they have separate chemical properties.

Uniform, identical bricks 20 cm long are stacked so that 4 cm of each brick extends beyond the brick beneath. How many bricks can be stacked in this way before the stack falls over?

How many layers of material were the roads made of? a. two c. four b. three d. five

Red light has a shorter wavelength than yellow light.

Approximately what is the parallax angle of a star that is 20 light-years away?

If the Earth and distant stars were stationary (motionless) in space, what would we observe about the wavelength from these stars? A. Wavelengths measured would match the actual wavelengths emitted. B.

Two fire trucks with sirens speeds towards and away from an observer. Which statement is true involving the Doppler effect observed by the observer?