Leap Science

Use the information  to answer the question.  
 Pierre wants to build a model of a ramp that would be safe for students who use wheelchairs. He knows that to be safe, a wheelchair ramp should not drop more than 10 centimeters for every 120 centimeters of ramp length. Pierre has the following materials:  
• a ball that will roll the way a wheelchair rolls
• a stopwatch to time the ball as it rolls
• a board that can be used as a small ramp
• blocks of wood to prop up the board at different heights
• a meterstick to measure distance                                    
Which items are necessary for Pierre to build a correct model of the ramp?  

• . the stopwatch and the ball only 
• the meterstick and the board only 
• . the meterstick, the board, and the blocks of wood only 
• the board, the blocks of wood, and the ball only 

Which of these statements represents Mabel’s revised understanding of sunflower growth?Mabel read that regular heavy watering promotes growth in sunflower plants. She planted 6 plots of sunflowers with 5 plants each and watered each plot with a different amount of water. The table shows her results.
  Plot Number Daily Amount of Water per Plant Average Final Height 1 1 liter 122 centimeters 2 2 liters 155 centimeters 3 3 liters 190 centimeters 4 4 liters 216 centimeters 5 5 liters 206 centimeters 6 6 liters 168 centimeters
Which of these statements represents Mabel’s revised understanding of sunflower growth?

• . Heavy watering on a regular schedule promotes sunflower growth. 
• Some plants respond better to watering, while others respond better to light. 
• . Water promotes growth up to a point, beyond which it stunts growth. 
• Some sunflower plants need less water than others.

Joyce put 200 milliliters of water in a beaker, put a thermometer in it, and heated it until it started to boil. She recorded a temperature of 100ºC when it started to boil. She repeated the process with 400 milliliters of water. What would be the temperature when this second sample started to boil?  

• . twice as high as the first sample’s 
• slightly higher than the first sample’s 
• half as high as the first sample’s 
• the same as the first sample’s

Jo Anne took a large beaker of clean water and carefully added one drop of blue food coloring to the edge of the water’s surface. She did not touch or move the beaker. At first, she saw blue streaks as the food coloring sank into the water, but gradually the color of the entire beaker of water became evenly blue. What caused the blue food coloring to be mixed throughout the water? 

• Water molecules hitting the food coloring molecules caused the mixing. 
• Light shining on the surface of the water caused the mixing. 
• . A chemical reaction between the water and the food coloring formed a new, light blue compound. 
• The water interacted with the food coloring, causing the blue color to fade.  

Jerry threw a ball into the air. It followed a curved path and soon fell to the ground because

• .  air friction stopped the ball.
• gravity changed the ball’s direction
• .  the ball was not thrown hard enough
• the ball was not thrown straight up

Denise was driving east over a hill in the afternoon, shortly after a rain shower. Suddenly the sun broke through the clouds, and she saw a rainbow ahead of her. Which of the following made the rainbow possible?

• Sunlight can be separated into all the colors of the rainbow.
• .  Water reflects sunlight like a mirror to make it look colored
• Overhead black clouds reflect in puddles to cause a mirage.
• Air pollution causes the sky to look colored under these conditions.  

Which statement about plant and animal cells is true?  

• Both have a cell wall to give them support.
• Both have a large vacuole to store water.
• Both use mitochondria to produce energy.
• Both use chloroplasts to store energy

The process of cellular respiration occurs in

• both plant and animal cells.
• plant cells only.
• animal cells only.
• neither plant nor animal cells.

Features of plant cells that clearly make them different from animal cells are

• a larger nucleus and fewer chromosomes
• a rigid cell wall and chloroplasts
• more cytoplasm and smaller vacuoles
• a changing size and indefinite shape

Which of these are not represented in the food web?

• producer
• primary consumer
• secondary consumer
• decomposer