Claim-Evidence-Reasoning from Electric and Magnetic Forces Scenario

Many hotels now use key cards to access their rooms. Key cards are more cost-efficient and secure than traditional keys. In a magnetic strip card, the strip is made of tiny iron-based pieces in a plastic film. The pieces are very small bar magnets that can have their polarity changed to either north or south pole directions. When the card is blank, all of the magnets are polarized in the same direction. Through a process called flux reversal, the polarity is changed so that it can be used in the reader. Since the process creates either N-N or S-S polarization, the card can easily be used in correspondence with the binary code system for computers.

Prompt

Write a scientific explanation that explains how magnetism is used to create a key card that only opens one room.

While studying chemical reactions and conservation of matter, sarah's class conducted a variety of experiments. sarah and her lab partner found the mass of a wax candle and placed the candle in a flask. the students lit the candle and let it burn to completion. all that was left was wax and charred candle wick. per their teacher's instructions, the students found the mass of the products. their data can be seen in the data table. formulate a hypothesis the students could test to explain why the experiment did not support the law of conservation of matter. a) the students could repeat the experiment using different candles; there might have been a flaw in the candle. b) the experiment should be repeatable. the students should run several trials and then take an average of the after mass in each trial. c) the students should have someone in the class check their measurement skills as they repeat the experiment. they may have made an error using the balance. d) the students should burn the candle in a container that has some type of lid so that any gas that is a product of the reaction can be contained and massed. submit