Which would be best categorized as heat transfer by convection?
a. Wearing a white shirt to stay cool on a summer day
b. Noodles rising and falling in a pot of boiling water
c. Touching a metal spoon that is sitting in a pot of boiling water
d. Using a heating blanket to get warm
Homework: STATIC ELECTRICITY REVIEW SHEET
RETAKE FOR UNIT TEST ON ENERGY FRIDAY IF SCORE WAS 80% AND BELOW.
2nd SET of Vocabulary Words due on Friday - February 17th
Please visit QUIZLET for practice.
Tuesday, February 14, 2017
Monday, February 13, 2017
HOMEWORK FOR TONIGHT:
5 minute vocabulary - Heat
-Explain the term
- Write the word in a sentence
After 5 min vocabulary:
Brain Pop Video with graphic organizer (Periods 6-7) STATIC ELECTRICITY
Period 5 : QUIZLET.LIVE practice review
Next students will complete the following stations:
A. Lab Activity – Separating Salt from Pepper
B. Quizlet Practice
C. USA Test Prep Practice
D. Guided Reading (Static Electricity)
Closing: Explain what static electricity is. Use examples if needed.
HOMEWORK FOR TONIGHT:
Website link: http://www.ck12.org/book/CK-12-Physical-Science-Concepts-For-Middle-School/section/5.64/
Directions: READ THE ARTICLE AND VIEW THE VIDEOS ON THE ABOVE LINK. Answer the questions at the bottom of this reading handout.
You’re a thoughtful visitor, so you wipe your feet on the welcome mat before you reach out to touch the brass knocker on the door. Ouch! A spark suddenly jumps between your hand and the metal, and you feel an electric shock.
Q: Why do you think an electric shock occurs?
A: An electric shock occurs when there is a sudden discharge of static electricity.
Static electricity is a buildup of electric charges on objects. Charges build up when negative electrons are transferred from one object to another. The object that gives up electrons becomes positively charged, and the object that accepts the electrons becomes negatively charged. This can happen in several ways.
One way electric charges can build up is through friction between materials that differ in their ability to give up or accept electrons. When you wipe your rubber-soled shoes on the wool mat, for example, electrons rub off the mat onto your shoes. As a result of this transfer of electrons, positive charges build up on the mat and negative charges build up on you.
Once an object becomes electrically charged, it is likely to remain charged until it touches another object or at least comes very close to another object. That’s because electric charges cannot travel easily through air, especially if the air is dry.
Q: You’re more likely to get a shock in the winter when the air is very dry. Can you explain why?
A: When the air is very dry, electric charges are more likely to build up objects because they cannot travel easily through the dry air. This makes a shock more likely when you touch another object.
What happens when you have become negatively charged and your hand approaches the metal doorknocker? Your negatively charged hand repels electrons in the metal, so the electrons move to the other side of the knocker. This makes the side of the knocker closest to your hand positively charged. As your negatively charged hand gets very close to the positively charged side of the metal, the air between your hand and the knocker also becomes electrically charged. This allows electrons to suddenly flow from your hand to the knocker. The sudden flow of electrons is static discharge. The discharge of electrons is the spark you see and the shock you feel.
Another example of static discharge, but on a much larger scale, is lightning. You can see how it occurs in the following diagram (Figure below).
During a rainstorm, clouds develop regions of positive and negative charge due to the movement of air molecules, water drops, and ice particles. The negative charges are concentrated at the base of the clouds, and the positive charges are concentrated at the top. The negative charges repel electrons on the ground beneath them, so the ground below the clouds becomes positively charged. At first, the atmosphere prevents electrons from flowing away from areas of negative charge and toward areas of positive charge. As more charges build up, however, the air between the oppositely charged areas also becomes charged. When this happens, static electricity is discharged as bolts of lightning.
· Static electricity is a buildup of electric charges on objects. It occurs when electrons are transferred from one object to another.
· A sudden flow of electrons from one charged object to another is called static discharge.
· Examples of static discharge include lightning and the shock you sometimes feel when you touch another object.
1. What is static electricity?
2. How does static discharge occur?
3. Explain why a bolt of lightning is like the spark you might see when you touch a metal object and get a shock.