Sc.5.P.8.3

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?

• A.  use a magnet to pull the iron filings from the salt
• add food coloring to the mixture to make the salt change color
• 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

Carrie has a container that contains thousands of mixed glass beads and iron beads of different shapes and sizes.
Which of the following is the best way to separate them?

• The glass beads will float, so she could add water to the container and the glass will float to the top
• The iron beads are magnetic, so she could separate the glass from the iron with a strong magnet
• The iron beads might be heavier, so she could shake the container until the iron beads settle to the bottom
• The iron beads are smaller, so she could pour the beads through a strainer and the glass beads will separate

Imagine you have a bucket of saltwater.
Which of the following would be the best way to remove the water so that you're left with only salt?

• Stir the saltwater for a long time. The salt will form a crystal.
• Leave the saltwater to sit for a long time. The salt will settle to the bottom
• Boil the saltwater. The water will evaporate and only the salt will remain
• Freeze the saltwater. The water will sink to the bottom and the salt will rise to the top

Abdul uses sugar cubes to sweeten his tea. He wonders whether stirring his tea will make the sugar cube dissolve faster or slower. If Abdul stirs his tea, what effect does it have on the rate at which the sugar cube dissolves?  

• The rate that the sugar cube dissolves will speed up
• The rate that the sugar cube dissolves will slow down
• The rate that the sugar cube dissolves will remain the same
• The rate that the sugar cube dissolves will slow down and then stop

Which of the following solids will not dissolve in boiling water?

• baking soda
• sand
• sugar
• table salt

Imagine that you have four buckets full of dark, muddy water. One bucket is frozen, one bucket is boiled, one bucket is shaken up, and one bucket is passed through a paper filter.
Which bucket is most likely to become lighter in color?

• The frozen bucket, because the mud separates from the water
• The shaken bucket, because shaking causes the mud to dissolve
• The boiled bucket, because the dirt in the muddy water evaporates
• The filtered bucket, because larger particles of dirt were strained out

Jason has a mixed container of iron pellets, foam pellets, glass pellets, and salt pellets. He needs to do the following things to separate these solids:  
 A.  Add water to the container and stir to dissolve the salt.  
B.  Heat the water until it evaporates and leaves the salt.  
C.  Remove the iron pellets with a magnet.  
 D.  Collect the floating foam pellets and the glass ones that have stuck to the bottom.
Which answer choice puts these steps in the correct order?

•  A, C, B, D
• C, A, D, B
• D, A, B, C
• B, D, C, A 

Imagine a thick 10 kilogram block of soap and a thin 10  kilogram sheet of soap.
Which answer correctly explains which will dissolve first when they are both placed underwater?

• The sheet will dissolve first because it has more surface area.
• The sheet will dissolve first because it has less mass than the block
• The block will dissolve first because it is less spread out than the sheet
• The sheet and the block weigh the same, so they will take the same amount of time to dissolve

Kayla wants to know if a sugar cube in a bowl of water will dissolve more quickly if it is stirred with a spoon than if it is left alone.
Which answer explains the effect that stirring will have?

• Stirring makes the sugar move around, and it dissolves more slowly because it is not staying still
• The sugar will dissolve more slowly because the movement of the water makes it stick together
• The sugar dissolves more quickly because the motion of the spoon creates heat, which melts the sugar
• When the sugar is stirred, more surface area will come into contact with the water, so the sugar dissolves more quickly.

Sam drops a sugar cube weighing one gram in a cup of cold water and lets it sit until the sugar cube dissolves.
Malcolm adds one gram of powdered sugar to a cup of hot water and stirs it with a spoon.
Rosa adds a one"gram packet of sugar granules to a cup of cold water and stirs it with a spoon. Angela adds a sugar crystal weighing one gram to a cup of hot water and does not stir it.  
Whose sugar is most likely to dissolve the fastest, and whose is slowest?

• Malcolm's sugar dissolves fastest, and Sam's dissolves slowest
• Rosa's sugar dissolves fastest, and Malcolm's dissolves slowest.
• Sam's sugar dissolves fastest, and Angela's dissolves slowest
• Angela's sugar dissolves fastest, and Rosa's dissolves slowest