2nd Grade Science : Physical Science
Study concepts, example questions & explanations for 2nd Grade Science
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Example Questions
Example Question #91 : Physical Science
Which of these photos demonstrates a change from heating or cooling that cannot be reversed?
The photo that demonstrates a change that cannot be reversed is the plate of pancakes. Water that has been frozen into snow can be turned back to a liquid, and ice cream and popsicles can be refrozen if melted. Once the ingredients are mixed into a batter and then heated, the pancakes cannot be turned into mixture again.
Example Question #8 : Argue Changes Caused By Heating/Cooling Can't Be Reversed
The photo below is an example of a change that cannot be reversed.
False
True
True
The photo is an example of a change that can't be reversed. Once the marshmallows have been roasted and start to cook, they cannot be changed back. There is no way to change melted marshmallows back to their original form.
Example Question #92 : Physical Science
The photo below is an example of a heating or cooling change that cannot be reversed.
False
True
True
The photo demonstrates a change that cannot be reversed. Once the toast is cooked and the butter melts into it, the changes cannot be reversed. Even if the toast is put into the refrigerator, it will not return to a piece of plain bread. A chemical change has taken place and cannot be reversed.
Example Question #10 : Argue Changes Caused By Heating/Cooling Can't Be Reversed
Which answer choice is a change caused by heating or cooling?
Making a salad
Cutting a banana
Baking a cake
Washing your clothes
Baking a cake
Baking a cake is a change that is caused by heat. The batter is mixed together, and heat is applied to create a chemical change while the food is baking. It cannot be reversed and returned to a mixture or the individual ingredients.
Example Question #1 : Argue Changes Caused By Heating/Cooling Can Be Reversed
An example of a change caused by heating or cooling that can be reversed would be the melting of a crayon and then freezing it back into a solid cube.
False
True
True
The statement above is a true statement and example of how heating and cooling can be reversed. If you melt a crayon, it goes from a solid to a liquid. This can be reversed, and the crayon can be returned to a solid-state by freezing or cooling it. Some changes cannot be reversed, but this example can be reversed.
Example Question #1 : Argue Changes Caused By Heating/Cooling Can Be Reversed
Becca says that some heating changes can be reversed. She gives the example of melting butter. She says that you can turn a solid piece of butter into a liquid and then turn it back to a solid. Her friend Melva disagrees and says butter cannot be changed back and forth.
Who is correct, and why?
There is not enough information to tell who is correct.
Melva; she is correct because butter cannot be changed. If the butter is turned into a liquid it cannot be reversed and turned back to a solid.
Neither; both of the girls are wrong
Becca; she is correct because the changes to butter can be reversed. Becca could melt the butter by applying heat and then put it back into the refrigerator to cool it down and make it solid again.
Becca; she is correct because the changes to butter can be reversed. Becca could melt the butter by applying heat and then put it back into the refrigerator to cool it down and make it solid again.
Butter is an excellent example of a heating change that can be reversed. Becca can melt butter and then cool it to reverse the effects. Melva disagreed with her but is unfortunately wrong in this case. Some heating and cooling changes can be reversed.
Example Question #91 : Physical Science
Which material can be heated or cooled, and then have the changes reversed?
Ice cube
Egg
Cake
Bread
Ice cube
Some objects or materials can be heated or cooled, and the changes caused can be reversed. An ice cube could have the changes applied to it reversed. If you heat an ice cube it will melt, you can refreeze it to turn it back to a solid. If you toast bread, bake a cake, or cook an egg, that change cannot be reversed.
Example Question #2 : Argue Changes Caused By Heating/Cooling Can Be Reversed
Will says some changes caused by heating cannot be reversed. Angelo says some changes can be reversed.
Their father takes a popsicle out of the freezer and sets it on the counter. The popsicle begins to melt. He gets a call and puts it back into the freezer.
Using this example who is correct, Will or Angelo, and why?
Will; He is correct because this is a change that cannot be reversed. Once the popsicle has started to melt, there is no changing that.
There is not enough information to decide who is correct.
Angelo; He is correct because this is a change that can be reversed. If the popsicle were melting and put back into the freezer, it would refreeze and become solid again.
Neither of the boys is correct.
Angelo; He is correct because this is a change that can be reversed. If the popsicle were melting and put back into the freezer, it would refreeze and become solid again.
In the situation presented, Angelo is correct. The changes to the popsicle can be reversed. Once it has been heated up and starts to melt, there is a change. In this case, their father puts it back into the freezer when he gets the call; this would cause the popsicle to refreeze. In some instances, these changes can not be reversed, but in this example, it is possible.
Example Question #241 : 2nd Grade Science
Which photo represents a heating or cooling change that can be reversed?
The photo that represents a heating or cooling change that can be reversed is the candle with melting wax. Once the candle is no longer lit, the wax will reharden and no longer will be a liquid. Baking a cake, heating toast, and lighting fireworks are all examples of applying heat in a way that cannot be reversed.
Example Question #3 : Argue Changes Caused By Heating/Cooling Can Be Reversed
An example of a change caused by heating or cooling that can be reversed would be the melting of a candy bar and then putting it into the refrigerator to reset the chocolate.
True
False
True
The statement above is a true statement and example of how heating and cooling can be reversed. If you melt a candy bar, the chocolate goes from a solid to a liquid. This can be reversed, and the candy bar can be returned to a solid-state by freezing or cooling it. Some changes cannot be reversed, but this example can be reversed.
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