Surely, you have noticed the tall poles along the roadside. Do you know what is on top of those poles? Thats right, wires that carry electric current. These wires carry electric current to your home. But what is electric current? Electric current is actually the flow of electrons. You may recall, an electron is the outer-most particle in an atom. They have a negative charge. Electricity is the continuous flow of these particles. Electrons are able to move through wires. Their speed can even be measured. The SI unit for electric current (or speed) is the ampere (A). Ampere is often shortened to amp. Electric current may flow in just one direction, or it may keep reversing direction. Direct current (DC) flows in only one direction. Direct current is what is used in devices like flashlights. Alternating current (AC) flows in two directions. This is the type of current that flows into your home through wires.

Question: "How many directions is the current flowing in that arrives through wires into our homes?"

Response: "Two directions"
OPTIONS:
- no
- yes

A: yes

Josie started planning her new garden in the winter. She chose flowers and vegetables that could grow in her area. She looked through the seed magazines. She ordered the tastiest kind of each vegetable and the prettiest kind of each flower. She talked to a friend about her plans. It seemed like the snow would never melt. But Josie didn't have to wait for spring to get started. Six weeks before the last frost, Josie planted seeds indoors. The tiny seedlings pushed up through the soil and began to grow. Finally spring arrived. Each day, Josie moved the seedlings outside for a few hours so they could get used to the cooler temperatures. Josie worked in her garden, digging the soil. She added a special growing mix from the garden store to make the soil better. When everything was ready, she removed the seedlings from their trays and planted them in her garden. The warm sun and rich soil helped her vegetables and flowers grow.

Question: "When did Josie move the seedlings outside for a few hours so they could get used to the cooler temperatures?"

Response: "Once spring arrived"
OPTIONS:
- no
- yes

A: yes

When you get sick, your body springs to action. Your body starts to fight the illness. Thats why you want to eat right and get plenty of sleep. You need a strong immune system to fight off illness. Plants dont have an immune system. That does not mean they do not get sick. Plants are affected by disease just like us. Typically, their first line of defense is the death of part of the plant. This prevents the infection from spreading. Many plants also produce special chemicals to fight disease. For example, willow trees produce a chemical to kill the bacteria. The same compound is used in many acne products. You can see a picture of a willow tree in Figure Plants may be smarter than we think. No, they cannot talk to each other. They may be able to send messages, though.

Question: "How might death of part of a plant help the plant?"

Response: "It will keep water from flowing"
OPTIONS:
- no
- yes

A:
no