Science UIL 2

1.        Maria poured three tablespoons of oil into a glass of water.  She stirred the water and then set the glass aside for one hour.  When she looked at the glass again, the oil had floated to the top.  What is the best explanation for this?

• A.   Oil is denser than water.

• A.   Oil is less dense than water.

• Oil needs a longer time to dissolve.

• A.   Maria put too much oil in the water.

1.        A student is asked to design a sleeve for a cup that will insulate thermal energy and not feel hot to the touch when the cup is filled with hot liquid. The student has four materials to choose from.  Which of these materials is least useful as an insulator?

• A.   Cardboard

• A.   Aluminum

• A.   Rubber

• A.   Plastic

1.        Students are using a spring scale to pull a 30-gram weight straight across a wooden table.  The students will then pull the 30-gram weight across the same distance on a marble surface and then a carpeted surface.  Which question is this investigation most likely designed to answer?

• How do spring scales affect weight?

•   How does the force of a weight affect a spring scale?

•   How do surfaces affect the amount of force needed to move a weight?

•   How does mass affect the force needed to move objects?

    Which shows one example of a physical change and one example of a chemical change?

•   Boiling water and melting wax.

•   Rusting iron and baking a cake.

•   Dissolving powder and shredding paper.

•   Freezing water and burning coal.

1.        An ice cube is put into a heated pan.  What will most likely happen to the molecules in the ice as the ice is heated?

• A.   The molecules will begin to move slower.

• A.   The molecules will begin to move faster.

• A.   The molecules will begin to increase in density.

• A.   The molecules will begin to condense in the air.

1.        According to Newton’s second law of motion, in which of these situations is the object accelerating?

• A.   A book on a shelf.

• A.   A rock sitting on the ground.

• A.   A helium balloon tied to a lamp post.

• A.   A ball that has been thrown upward.

1.        A student dipped a strip of aluminum and a strip of iron into water.  The student then exposed the strips to air for one week.  What was most likely observed one week later?

• A.   The iron strip formed rust.

• A.   The aluminum strip formed rust.

• A.   Both of the metal strips formed rust.

• A.   Neither of the metal strips formed rust.

1.        Solids have a definite shape and volume.  This is because –

• A.   the molecules in solids move past each other easily.

• A.   the molecules in solids stay in a definite location and vibrate.

• A.   the molecules in solids move freely in all directions.

• A.   the molecules in solids do not move at all.

1.        How does the flexible foam lining inside a bicycle helmet change the outcome of a collision so as to reduce the risk of head injury for a rider?

• A.   By reducing the rider’s change in velocity.

• A.   By transmitting the force away from the rider’s head.

• A.   By reducing the amount of the rider’s mass on which the force acts.

• A.   By increasing the time over which force is exerted on the rider.

1.        As a renewable resource, hydroelectricity is generating more attention as environmental concerns rise.  What is one advantage of using this as an energy source?  Hydroelectric energy -

• A.   reservoirs can be used for irrigation of crops.

• A.   may divert water and alter normal water flow.

• A.   might disrupt the movements of migrating salmon.

• B.   sometimes causes flooding in surrounding areas.