7.9b

Astronauts wear thick gloves when they perform a space walk outside the space station. The gloves provide protection against -

• low gravity.

• nearby comets.

• low oxygen.

• low temperatures.

How do astronauts counteract the effects of microgravity on their bones while they are in space?

• Monitor sensors outside the space station.

• Consume twice as many calories as normal.

• Use exercise equipment on the space station.

• Breathe at a faster rate than normal.

According to Table 1, which planet has the most elliptical orbit?

• 1. Planet A

• 1. Planet B

• Planet C

• 1. Planet D

Tags

7.9B

Infer: Scientists have discovered a new planet and are interested in determining how great its gravitational pull is on surrounding planets. What factors do they need to consider?

TEKS 7.9B

• 1. Velocity and mass

• 1. Mass and distance

• 1. Mass and volume

• 1. Density and distance

Tags

7.9B

The speed of a planet varies as it orbits the Sun. What causes the speed of a planet's orbit to change when it is closer to the Sun?

• Heat from the sun

• a reverse in the direction of the planet's orbit

• Gravity from the Sun

• an increase in the number of objects close to the Sun

Tags

7.9B

A comet is made up of different materials that hold together in space as the comet orbits. Which force holds a comet together and governs its motion?

• 1. gravitational force

• weak nuclear force

• strong nuclear force

• electromagnetic force

Tags

7.9B

What must happen in order for energy to transfer within a fluid by convection?

• The particles of one fluid must collide with those of another fluid.

• The particles of one fluid must move to another fluid.

• The energy must be carried upward by particles of the fluid.

• The energy must move out of the fluid to its surroundings.

Tags

7.8A

Select the correct answer for each box.

This causes the wax of the candle to melt away from the flame. ​ ​ ​ (a)  

This causes the heat to be felt by someone sitting near the candle.​ (b)  

This causes the flame to get longer and cool air to move into the bottom of the flame.​ (c)  

• Radiation

• Convection

• insulation

• conduction

Tags

7.8A

Two equal volume of water are in a large container, separated by a divider. The water on one side is at 60°C and the water on the other side is 40°C. How will you know when the container has reached thermal equilibrium once you have removed the divider?

• The temperature of the water on the warmer side will have cooled to 40°C.
  

• The temperature throughout the container will be approximately 50°C.
  

• The temperature of the water on the cooler side will have warmed to 60°C.
  

• Convection currents will prevent this system from reaching thermal equilibrium.

Tags

7.8B

7.8C

How well some materials conduct heat is shown in the table. Would acrylic or glass be a better material for an aquarium, if the goal is to keep an aquarium at a temperature that is cooler than the temperature of the room that it is kept in?

• 
  Acrylic because its lower conductivity value means it is less likely to transfer heat from the room to the aquarium.

• Acrylic because its higher conductivity means it is less likely to transfer heat from the room to the aquarium.

• Glass because its lower conductivity value means it is less likely to transfer heat from the room to the aquarium.

• Glass because its higher conductivity means it is less likely to transfer heat from the room to the aquarium.

Tags

7.8C

7.8B