For her science fair project, Marcy is investigating how levels of carbon dioxide affect plant growth. Which of the following is most important? 

• She needs to make sure her results match her predictions.
• She needs to make sure that her results contain both words and numbers.
• She needs to make sure that the explanation of her results is based on evidence. 
• She needs to make sure her results get published so that everyone can read them.

Which of the following questions could be answered by a scientific investigation?

• What color is the best to paint with?
• What animal makes a good pet?
• What is the best flavor of soft drink?
• What causes some metals to rust?

Maria and her brother like to go fishing at the lake on Saturdays. They wondered if fish were more likely to bite at one time of day than another. They decided to try an experiment the next two Saturdays.
On the first Saturday, it was hot and sunny, and they went fishing in the morning. Maria and her brother caught five fish. On the second day Saturday, it was overcast and cool, and they went fishing in the afternoon. They only caught three fish. Can they conclude that fish bite better in the morning?

• Yes. They caught more fish in the morning, so morning is a better time.
• Yes. It is more likely to be sunny in the morning, and the fish bite better when it is sunny.
• No. They will need to repeat their experiment several times, since the weather and times were different both days.
• No. They only did their experiment on Saturdays, so they don't know if they would get the same results on other days.

Dr. Jones thinks she has just discovered a new plant species. How should she best communicate her findings with other scientists?

• Try to find another plant to discover.
• Post her discovery for other scientists to test.
• Publish her discovery for other scientists to test.
• Call her friends and tell them about the discovery. 

Marc notices that when he looks at stars at night, some appear to be brighter than others. Which three factors affect how bright a star appears to an observer on Earth?

• The star's color, size, and distance from the Earth
• The star's energy, size, and temperature
• The star's size, temperature, and distance from Earth
• The star's movement, distance from Earth, and gravity. 

Ann and Cheryl are trying to write a general description of a planet that could apply to any planet in our Solar System. So far, their list looks like this:
1. Orbits the Sun
2. Is nearly round
What else can they add to the list?

• spins on its axis
• has at least one moon
• has water on its surface
• is always the same distance from the Sun

When comets come close to the Sun they develop a tail that glows so we can see it from Earth. Asteroids do not develop tails like this. In what other way are asteroids different from comets?

• Asteroids are rocky while comets are balls of ice and dust.
• Asteroids orbit planets while comets orbit the Sun
• Asteroids orbit outside the Solar System while comets do not.
• Asteroids are smooth and round while comets are lumpy shapes. 

Which answer describes how the inner planets are similar to each other?

• They are all the same size.
• They all have solid surfaces.
• They all have at least one moon.
• They all have a thick atmosphere.

During which part of the water cycle is water a gas?

• after it condenses
• when it evaporates
• as it becomes precipitation
• once it changes temperature

Which answer correctly explains the difference between sleet and hail?

• Sleet is usually part of a thunderstorm, and hail comes from layers of rain clouds.
• Sleet is smaller than hail and usually falls in the winter, while hail usually falls in the summer. 
• Sleet and hail are the same except that sleet usually falls in summer and hail usually falls in winter.
• Sleet is snow that forms as it falls through cold air, and hail is rain that freezes when it hits the ground.