Science Topics 8-9

Ice cream in a bowl changed from solid to liquid in a few minutes. Which of the following most likely caused this change?

• Heat was added to the ice cream.

• Water evaporated from the ice cream.

• Heat was taken away from the ice cream.

• A chemical changed occurred to the ice cream.

Thomas and Julie wanted to find out which material would insulate their teacher's coffee cup and keep the coffee hot for the longest period of time. They first wrapped her cup with bubble wrap and recorded the temperature of the coffee once every 15 minutes for 2 hours. They repeated the investigation. This time they used newspaper instead of bubble wrap, but they got the same results for both materials. What could they do to make sure their results are valid?

• Use tea instead of coffee.

• Repeat their investigation.

• Use a different thermometer.

• Conduct their investigation in a colder room.

Janice found two seashells when she went to the beach. They appear to be almost the same size, but they have different shapes. How could she figure out if their volume is the same?

• Fill each seashell with water to see if they hold the same amount.

• Find the mass of each seashell on a balance to see if they have the same mass.

• Measure the length of each seashell with a measuring tape to see if they are the same length.

• Drop each shell into a graduated cylinder with water to see if they raise the water level equally.

Arjun placed a salt cube in a cup of water. He wonders whether stirring the water will make the salt cube dissolve faster or slower. If Arjun stirs his cup of water, what effect does it have on the rate at which the salt cube dissolves?

• The rate that the salt cube dissolves will speed up.

• The rate that the salt cube dissolves will slow down.

• The rate that the salt cube dissolves will remain the same.

• The rate that the salt cube dissolves will slow down and then stop.

Olivia blew up a balloon until it was completely full and as big as a soccer ball. Which of the following correctly describes the air inside the balloon?

• The air is a gas that cannot be contained by any means.

• The air is a gas that always forms a round shape when compressed.

• The air is a gas that expands to evenly fill the space inside the balloon.

• The air is a gas that will flow evenly and steadily from inside the balloon if punctured.

George's science teacher has a mixture of table salt and iron filings. Which of the following would be the best way to separate the salt and the iron filings?

• Use a magnet to pull the iron filings from the salt.

• Use a sieve to separate the mixture by particle size.

• Pour them into a beaker of water and see if the iron filings float.

• Heat up the mixture to see if the salt or the iron filings will burn away.

Kyle and Jan are comparing two samples of matter. They make a table of the properties of each sample. Which property provides the best evidence that both samples are solids rather than liquids?

• mass

• color

• shape

• volume

Which of the following must be true for scientific results to be valid?

• The results should be drawn in a graph.

• The results should be based on evidence.

• The results should support the ideas of other scientists.

• The results should match the predictions of the scientist.

Jerome put water in the freezer and made ice. Which of the following happened?

• Water physically changed from a solid to a liquid.

• Water physically changed from a liquid to a solid.

• Water chemically changed from a solid to a liquid.

• Water chemically changed from a liquid to a solid.

When Elsa placed a substance into a container it was round and had a volume of one liter. When she placed the same substance in a much larger container it was now rectangular, but still had a volume of one liter. What state of matter is the substance in?

• gas

• solid

• liquid

• evaporated