Unit 6     返回中級閱讀第五冊總表     Unit 8 

Unit 7: Chalkboards

Chalkboards and whiteboards are very valuable tools for teachers. They allow them to quickly print out things or show ideas for all the students to see easily. Teachers can write key words on the board for students to copy or they can draw pictures to explain difficult concepts. And when they are finished with the board, or run out of room (space), it can be easily erased and used again and again. 

Chalkboard erasers quickly become dirty with chalk dust and should be cleaned regularly or they will not work very well. You can tap them against a wall or hit them with something to remove the excess dust. Be careful not to inhale (breathe in) it though because it isn’t very good for you. It is best to clean them outside. You can also wear a mask or cover your mouth to prevent breathing in too much of the unhealthy dust. Chalk dust is especially harmful to asthma sufferers. 

In many classrooms whiteboards have replaced chalk boards, especially computer labs, because dry-erase markers produce far less dust that can harm sensitive computer parts. Though dust from whiteboards is also harmful to breathe in, it is much heavier than chalk dust which can remain airborne for extended periods and quickly settles to the floor. This makes it less likely that you will breathe it in.

Both chalkboards and whiteboards have their pros (benefits) and cons (faults), but, as a teacher, I find whiteboards less messy and easier to use. I also dislike having my shirt covered in chalk dust that blackboards collect. But most of all, I hate the sound of fingernails accidentally scratching the chalkboard. It is possibly the most irritating sound in the world. 

Picture 1: Peter is wiping off the chalkboard because his teacher asked him to do it. He uses the chalk brush (eraser) to erase the math problems that his teacher solved for him.

Picture 2: Peter is cleaning the eraser by beating it with a stick.